24 December 2020
17:51
Acute exacerbation of COPD
Acute exacerbations of COPD are one of the most common reasons why people present to hospital in developed countries.
Features
· increase in dyspnoea, cough, wheeze
· there may be an increase in sputum suggestive of an infective cause
· patients may be hypoxic and in some cases have acute confusion
The most common bacterial organisms that cause infective exacerbations of COPD are:
· Haemophilus influenzae (most common cause)
· Streptococcus pneumoniae
· Moraxella catarrhalis
Respiratory viruses account for around 30% of exacerbations, with the human rhinovirus being the most important pathogen.
NICE guidelines from 2010 recommend the following:
· increase frequency of bronchodilator use and consider giving via a nebuliser
· give prednisolone 30 mg daily for 5 days
· it is common practice for all patients with an exacerbation of COPD to receive antibiotics. NICE do not support this approach. They recommend giving oral antibiotics 'if sputum is purulent or there are clinical signs of pneumonia'
· the BNF recommends one of the following oral antibiotics first-line: amoxicillin or clarithromycin or doxycycline.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Alpha-1 antitrypsin deficiency
Alpha-1 antitrypsin (A1AT) deficiency is a common inherited condition caused by a lack of a protease inhibitor (Pi) normally produced by the liver. The role of A1AT is to protect cells from enzymes such as neutrophil elastase. It classically causes emphysema (i.e. chronic obstructive pulmonary disease) in patients who are young and non-smokers.
Genetics
· located on chromosome 14
· inherited in an autosomal recessive / co-dominant fashion*
· alleles classified by their electrophoretic mobility - M for normal, S for slow, and Z for very slow
· normal = PiMM
· homozygous PiSS (50% normal A1AT levels)
· homozygous PiZZ (10% normal A1AT levels)
Features
· patients who manifest disease usually have PiZZ genotype
· lungs: panacinar emphysema, most marked in lower lobes
· liver: cirrhosis and hepatocellular carcinoma in adults, cholestasis in children
Investigations
· A1AT concentrations
· spirometry: obstructive picture
Management
· no smoking
· supportive: bronchodilators, physiotherapy
· intravenous alpha1-antitrypsin protein concentrates
· surgery: lung volume reduction surgery, lung transplantation
*trusted sources are split on which is a more accurate description
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Chest x-ray: white lung lesions
There are numerous causes of white shadowing in the lungs including:
· consolidation
· pleural effusion
· collapse
· pneumonectomy
· specific lesions e.g. tumours
· fluid e.g. pulmonary oedema
If there is a 'white-out' of a hemithorax it is useful to assess the position of the trachea - is it central, pulled or pushed from the side of opacification.
| Trachea pulled toward the white-out | Trachea central | Trachea pushed away from the white-out |
| Pneumonectomy Complete lung collapse e.g. endobronchial intubation Pulmonary hypoplasia | Consolidation Pulmonary oedema (usually bilateral) Mesothelioma | Pleural effusion Diaphragmatic hernia Large thoracic mass |
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| © Image used on license from Radiopaedia | |
Lung collapse - note how the trachea is pulled towards the side of the white-out
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| © Image used on license from Radiopaedia | |
Pleural effusion - note how the trachea (blue) is pushed away the side of the white-out. The other signs of a positive mass effect include leftward bowing of the azygo-oesophageal recess (yellow) and splaying of the ribs on the right (red)
For more information check out the link to the superb Radiology Masterclass website.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Aspiration pneumonia
Aspiration pneumonia is a pneumonia that develops as a result of foreign materials gaining entry to the bronchial tree, usually oral or gastric contents such as food and saliva. Depending on the acidity of the aspirate a chemical pneumonitis can develop, as well as bacterial pathogens adding to the inflammation.
Aspiration pneumonia often results from an incompetent swallowing mechanism, such as those that occur in neurological disease or injury such as stroke, multiple sclerosis and intoxication. Iatrogenic causes, such as intubation, can also result in aspiration pneumonia developing. Risk factors for the development of aspiration pneumonia include:
· Poor dental hygiene
· Swallowing difficulties
· Prolonged hospitalization or surgical procedures
· Impaired consciousness
· Impaired mucociliary clearance
The right middle and lower lung lobes are the most common sites affected, due to the larger calibre and more vertical orientation of the right main bronchus.
The bacteria often implicated in aspiration pneumonia are aerobic, and often include:
· Streptococcus pneumoniae
· Staphylococcus aureus
· Haemophilus influenzae
· Pseudomonas aeruginosa
Other aerobic, and anaerobic, organisms can also result in aspiration pneumonia, but are less common.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Asthma: management in adults
NICE released guidance on the management of asthma in 2017. These followed on quickly from the 2016 British Thoracic Society (BTS) guidelines. Given previous precedents where specialist societies or Royal colleges eventually default/contribute to NICE, we have followed the NICE guidance for the notes and questions.
One of the key changes is in 'step 3' - patients on a SABA + ICS whose asthma is not well controlled should be offered a leukotriene receptor antagonist, not a LABA
NICE do not follow the stepwise approach of the previous BTS guidelines. However, to try to make the guidelines easier to follow we've added our own steps:
| Step | Notes |
| 1 Newly-diagnosed asthma | Short-acting beta agonist (SABA) |
| 2 Not controlled on previous step OR Newly-diagnosed asthma with symptoms >= 3 / week or night-time waking | SABA + low-dose inhaled corticosteroid (ICS) |
| 3 | SABA + low-dose ICS + leukotriene receptor antagonist (LTRA) |
| 4 | SABA + low-dose ICS + long-acting beta agonist (LABA) Continue LTRA depending on patient's response to LTRA |
| 5 | SABA +/- LTRA Switch ICS/LABA for a maintenance and reliever therapy (MART), that includes a low-dose ICS |
| 6 | SABA +/- LTRA + medium-dose ICS MART OR consider changing back to a fixed-dose of a moderate-dose ICS and a separate LABA |
| 7 | SABA +/- LTRA + one of the following options: · increase ICS to high-dose (only as part of a fixed-dose regime, not as a MART) · a trial of an additional drug (for example, a long-acting muscarinic receptor antagonist or theophylline) · seeking advice from a healthcare professional with expertise in asthma |
Maintenance and reliever therapy (MART)
· a form of combined ICS and LABA treatment in which a single inhaler, containing both ICS and a fast-acting LABA, is used for both daily maintenance therapy and the relief of symptoms as required
· MART is only available for ICS and LABA combinations in which the LABA has a fast-acting component (for example, formoterol)
It should be noted that NICE does not advocate changing treatment in patients who have well-controlled asthma simply to adhere to the latest guidance.
Table showing examples of inhaled corticosteroid doses
Frustratingly, the definitions of what constitutes a low, moderate or high-dose ICS have also changed. For adults:
· <= 400 micrograms budesonide or equivalent = low dose
· 400 micrograms - 800 micrograms budesonide or equivalent = moderate dose
· > 800 micrograms budesonide or equivalent= high dose.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Idiopathic pulmonary fibrosis
Idiopathic pulmonary fibrosis (IPF, previously termed cryptogenic fibrosing alveolitis) is a chronic lung condition characterised by progressive fibrosis of the interstitium of the lungs. Whilst there are many causes of lung fibrosis (e.g. medications, connective tissue disease, asbestos) the term IPF is reserved when no underlying cause exists.
IPF is typically seen in patients aged 50-70 years and is twice as common in men.
Features
· progressive exertional dyspnoea
· bibasal fine end-inspiratory crepitations on auscultation
· dry cough
· clubbing
Diagnosis
· spirometry: classically a restrictive picture (FEV1 normal/decreased, FVC decreased, FEV1/FVC increased)
· impaired gas exchange: reduced transfer factor (TLCO)
· imaging: bilateral interstitial shadowing (typically small, irregular, peripheral opacities - 'ground-glass' - later progressing to 'honeycombing') may be seen on a chest x-ray but high-resolution CT scanning is the investigation of choice and required to make a diagnosis of IPF
· ANA positive in 30%, rheumatoid factor positive in 10% but this does not necessarily mean that the fibrosis is secondary to a connective tissue disease. Titres are usually low
Management
Approach to management in IPF:
Conservative
· Best supportive care
· Oxygen
· Pulmonary Rehab
· Palliative care when appropriate
Medical
· Perfenidone - anti-fibrotic properties, can stabilize lung function
· Nintedanib
Surgical
· Lung transplant
Management
· pulmonary rehabilitation
· very few medications have been shown to give any benefit in IPF. There is some evidence that pirfenidone (an antifibrotic agent) may be useful in selected patients (see NICE guidelines)
· many patients will require supplementary oxygen and eventually a lung transplant
Prognosis
· poor, average life expectancy is around 3-4 years
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| © Image used on license from Radiopaedia | |
Chest X-ray shows sub-pleural reticular opacities that increase from the apex to the bases of the lungs
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| © Image used on license from Radiopaedia | |
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| © Image used on license from Radiopaedia | |
Chest X-ray and CT scan from a patient who presented with dyspnoea. The x-ray shows reitcular opacities predominantly in the bases. In addition the CT demonstrates honeycombing and traction bronchiectasis
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| © Image used on license from Radiopaedia | |
CT scan showing advanced pulmonary fibrosis including 'honeycombing'
From <https://www.passmedicine.com/review/textbook.php?s=#>
pulmonary fibrosis.
CT imaging
· honeycombing, reticular opacities, traction bronchiectasis, and anatomical distortion, more pronounced at the bases Ground-glass opacities are less of a feature of idiopathic pulmonary fibrosis
Spirometry
· restrictive ventilatory defect
Diffusing capacity for carbon monoxide
· reduced
Bronchoalveolar lavage
· not use for diagnosis as usually non-specific
From <https://mle.ncl.ac.uk/cases/page/18128/>
24 December 2020
17:51
Pleural effusion: causes
Pleural effusions may be classified as being either a transudate or exudate according to the protein concentration.
Transudate (< 30g/L protein)
· heart failure (most common transudate cause)
· hypoalbuminaemia (liver disease, nephrotic syndrome, malabsorption)
· hypothyroidism
· Meigs' syndrome
Exudate (> 30g/L protein)
· infection: pneumonia (most common exudate cause), TB, subphrenic abscess
· connective tissue disease: RA, SLE
· neoplasia: lung cancer, mesothelioma, metastases
· pancreatitis
· pulmonary embolism
· Dressler's syndrome
· yellow nail syndrome
Features
· dyspnoea, non-productive cough or chest pain are possible presenting symptoms
· classic examination findings include dullness to percussion, reduced breath sounds and reduced chest expansion
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Pulmonary function tests
Pulmonary function tests can be used to determine whether a respiratory disease is obstructive or restrictive. The table below summarises the main findings and gives some example conditions:
| Obstructive lung disease | Restrictive lung disease |
| FEV1 - significantly reduced FVC - reduced or normal FEV1% (FEV1/FVC) - reduced | FEV1 - reduced FVC - significantly reduced FEV1% (FEV1/FVC) - normal or increased |
| Asthma COPD Bronchiectasis Bronchiolitis obliterans | Pulmonary fibrosis Asbestosis Sarcoidosis Acute respiratory distress syndrome Infant respiratory distress syndrome Kyphoscoliosis e.g. ankylosing spondylitis Neuromuscular disorders Severe obesity |
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:51
Obstructive sleep apnoea/hypopnoea syndrome
Predisposing factors
· obesity
· macroglossia: acromegaly, hypothyroidism, amyloidosis
· large tonsils
· Marfan's syndrome
The partner often complains of excessive snoring and may report periods of apnoea.
Consequence
· daytime somnolence
· compensated respiratory acidosis
· hypertension
Assessment of sleepiness
· Epworth Sleepiness Scale - questionnaire completed by patient +/- partner
· Multiple Sleep Latency Test (MSLT) - measures the time to fall asleep in a dark room (using EEG criteria)
Diagnostic tests
· sleep studies (polysomnography) - ranging from monitoring of pulse oximetry at night to full polysomnography where a wide variety of physiological factors are measured including EEG, respiratory airflow, thoraco-abdominal movement, snoring and pulse oximetry
Management
· weight loss
· continuous positive airway pressure (CPAP) is first line for moderate or severe OSAHS
· intra-oral devices (e.g. mandibular advancement) may be used if CPAP is not tolerated or for patients with mild OSAHS where there is no daytime sleepiness
· the DVLA should be informed if OSAHS is causing excessive daytime sleepiness
· limited evidence to support use of pharmacological agents
From <https://www.passmedicine.com/review/textbook.php?s=#>
Frequent awakenings at night are actually more suggestive of central sleep apnoea. Polysomnography is required to assess which type of sleep apnoea syndrome is likely. EEG is recorded to identify various stages of sleep.
The respiratory pattern is monitored to detect apnoea and identify whether it is central or obstructive in nature.
Outpatient arterial oxygen saturation studies alone might identify multiple episodes of desaturation during sleep, but negative results would not rule out possible sleep apnoea syndrome.
Polysomnography includes multiple sleep tests and is the best choice.
24 December 2020
17:51
Oxygen therapy
The British Thoracic Society updated its guidelines on emergency oxygen therapy in 2017. The following selected points are taken from the guidelines. Please see the link provided for the full guideline.
In patients who are critically ill (anaphylaxis, shock etc) oxygen should initially be given via a reservoir mask at 15 l/min. Hypoxia kills. The BTS guidelines specifically exclude certain conditions where the patient is acutely unwell (e.g. myocardial infarction) but stable.
Oxygen saturation targets
· acutely ill patients: 94-98%
· patients at risk of hypercapnia (e.g. COPD patients): 88-92% (see below)
· oxygen should be reduced in stable patients with satisfactory oxygen saturation
Management of COPD patients
· prior to availability of blood gases, use a 28% Venturi mask at 4 l/min and aim for an oxygen saturation of 88-92% for patients with risk factors for hypercapnia but no prior history of respiratory acidosis
· adjust target range to 94-98% if the pCO2 is normal
Situations where oxygen therapy should not be used routinely if there is no evidence of hypoxia:
· myocardial infarction and acute coronary syndromes
· stroke
· obstetric emergencies
· anxiety-related hyperventilation
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Pleural effusion: investigation and management
The British Thoracic Society (BTS) produced guidelines in 2010 covering the investigation of patients with a pleural effusion.
Imaging
· posterioranterior (PA) chest x-rays should be performed in all patients
· ultrasound is recommended: it increases the likelihood of successful pleural aspiration and is sensitive for detecting pleural fluid septations
· contrast CT is now increasingly performed to investigate the underlying cause, particularly for exudative effusions
Pleural aspiration
· as above, ultrasound is recommended to reduce the complication rate
· a 21G needle and 50ml syringe should be used
· fluid should be sent for pH, protein, lactate dehydrogenase (LDH), cytology and microbiology
Light's criteria was developed in 1972 to help distinguish between a transudate and an exudate. The BTS recommend using the criteria for borderline cases:
· exudates have a protein level of >30 g/L, transudates have a protein level of <30 g/L
· if the protein level is between 25-35 g/L, Light's criteria should be applied. An exudate is likely if at least one of the following criteria are met:
o pleural fluid protein divided by serum protein >0.5
o pleural fluid LDH divided by serum LDH >0.6
o pleural fluid LDH more than two-thirds the upper limits of normal serum LDH
Other characteristic pleural fluid findings:
· low glucose: rheumatoid arthritis, tuberculosis
· raised amylase: pancreatitis, oesophageal perforation
· heavy blood staining: mesothelioma, pulmonary embolism, tuberculosis
Pleural infection
All patients with a pleural effusion in association with sepsis or a pneumonic illness require diagnostic pleural fluid sampling
· if the fluid is purulent or turbid/cloudy a chest tube should be placed to allow drainage
· if the fluid is clear but the pH is less than 7.2 in patients with suspected pleural infection a chest tube should be placed
Management of recurrent pleural effusion
Options for managing patients with recurrent pleural effusions include:
· recurrent aspiration
· pleurodesis
· indwelling pleural catheter
· drug management to alleviate symptoms e.g. opioids to relieve dyspnoea
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Acute asthma: features
Acute asthma is nearly always seen in patients who've got a history of asthma.
Features
· worsening dyspnoea, wheeze and cough that is not responding to salbutamol
· maybe triggered by a respiratory tract infection
Patients with acute severe asthma are stratified into moderate, severe or life-threatening
| Moderate | Severe | Life-threatening |
| PEFR 50-75% best or predicted Speech normal RR < 25 / min Pulse < 110 bpm | PEFR 33 - 50% best or predicted Can't complete sentences RR > 25/min Pulse > 110 bpm | PEFR < 33% best or predicted Oxygen sats < 92% Silent chest, cyanosis or feeble respiratory effort Bradycardia, dysrhythmia or hypotension Exhaustion, confusion or coma |
In addition, a normal pCO2 in an acute asthma attack indicates exhaustion and should, therefore, be classified as life-threatening.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Asthma: diagnosis
NICE released guidance on the management of asthma in 2017. These followed on quickly from the 2016 British Thoracic Society (BTS) guidelines. Given previous precedents where specialist societies or Royal colleges eventually default/contribute to NICE, we have followed the NICE guidance for the notes and questions.
NICE guidance has radically changed how asthma should be diagnosed. It advocates moving anyway from subjective/clinical judgements are more towards objective tests.
There is particular emphasis on the use of fractional exhaled nitric oxide (FeNO). Nitric oxide is produced by 3 types of nitric oxide synthases (NOS). One of the types is inducible (iNOS) and levels tend to rise in inflammatory cells, particularly eosinophils. Levels of NO therefore typically correlate with levels of inflammation.
Other more established objective tests such as spirometry and peak flow variability are still important.
All patients >= 5 years should have objective tests. Once a child with suspected asthma reaches the age of 5 years objective tests should be performed to confirm the diagnosis.
Diagnostic testing
Patients >= 17 years
· patients should be asked if their symptoms are better on days away from work/during holidays. If so, patients should be referred to a specialist as possible occupational asthma
· all patients should have spirometry with a bronchodilator reversibility (BDR) test
· all patients should have a FeNO test
Patients 5-16 years
· all patients should have spirometry with a bronchodilator reversibility (BDR) test
· a FeNO test should be requested if there is normal spirometry or obstructive spirometry with a negative bronchodilator reversibility (BDR) test
Patients < 5 years
- diagnosis should be made on clinical judgement
Specific points about the tests
FeNO
· in adults level of >= 40 parts per billion (ppb) is considered positive
· in children a level of >= 35 parts per billion (ppb) is considered positive
Spirometry
· FEV1/FVC ratio less than 70% (or below the lower limit of normal if this value is available) is considered obstructive
Reversibility testing
· in adults, a positive test is indicated by an improvement in FEV1 of 12% or more and increase in volume of 200 ml or more
· in children, a positive test is indicated by an improvement in FEV1 of 12% or more
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Kartagener's syndrome
Kartagener's syndrome (also known as primary ciliary dyskinesia) was first described in 1933 and most frequently occurs in examinations due to its association with dextrocardia (e.g. 'quiet heart sounds', 'small volume complexes in lateral leads')
Pathogenesis
· dynein arm defect results in immotile cilia
Features
· dextrocardia or complete situs inversus
· bronchiectasis
· recurrent sinusitis
· subfertility (secondary to diminished sperm motility and defective ciliary action in the fallopian tubes)
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Lung cancer: paraneoplastic features
Small cell
· ADH
· ACTH - not typical, hypertension, hyperglycaemia, hypokalaemia, alkalosis and muscle weakness are more common than buffalo hump etc
· Lambert-Eaton syndrome
Squamous cell
· parathyroid hormone-related protein (PTH-rp) secretion causing hypercalcaemia
· clubbing
· hypertrophic pulmonary osteoarthropathy (HPOA)
· hyperthyroidism due to ectopic TSH
Adenocarcinoma
· gynaecomastia
· hypertrophic pulmonary osteoarthropathy (HPOA)
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| © Image used on license from Radiopaedia | |
Hypertrophic pulmonary osteoarthropathy is a proliferative periostisis involving that typically involves the long bones. It is often painful.
*whilst it is traditionally taught that HPOA is most common with squamous cell carcinoma some studies indicate that adenocarcinoma is the most common cause e.g. https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4049689/
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Smoking cessation
NICE released guidance in 2008 on the management of smoking cessation. General points include:
· patients should be offered nicotine replacement therapy (NRT), varenicline or bupropion - NICE state that clinicians should not favour one medication over another
· NRT, varenicline or bupropion should normally be prescribed as part of a commitment to stop smoking on or before a particular date (target stop date)
· prescription of NRT, varenicline or bupropion should be sufficient to last only until 2 weeks after the target stop date. Normally, this will be after 2 weeks of NRT therapy, and 3-4 weeks for varenicline and bupropion, to allow for the different methods of administration and mode of action. Further prescriptions should be given only to people who have demonstrated that their quit attempt is continuing
· if unsuccessful using NRT, varenicline or bupropion, do not offer a repeat prescription within 6 months unless special circumstances have intervened
· do not offer NRT, varenicline or bupropion in any combination
Nicotine replacement therapy
· adverse effects include nausea & vomiting, headaches and flu-like symptoms
· NICE recommend offering a combination of nicotine patches and another form of NRT (such as gum, inhalator, lozenge or nasal spray) to people who show a high level of dependence on nicotine or who have found single forms of NRT inadequate in the past
Varenicline
· a nicotinic receptor partial agonist
· should be started 1 week before the patients target date to stop
· the recommended course of treatment is 12 weeks (but patients should be monitored regularly and treatment only continued if not smoking)
· has been shown in studies to be more effective than bupropion
· nausea is the most common adverse effect. Other common problems include headache, insomnia, abnormal dreams
· varenicline should be used with caution in patients with a history of depression or self-harm. There are ongoing studies looking at the risk of suicidal behaviour in patients taking varenicline
· contraindicated in pregnancy and breast feeding
Bupropion
· a norepinephrine and dopamine reuptake inhibitor, and nicotinic antagonist
· should be started 1 to 2 weeks before the patients target date to stop
· small risk of seizures (1 in 1,000)
· contraindicated in epilepsy, pregnancy and breast feeding. Having an eating disorder is a relative contraindication
Pregnant women
NICE recommended in 2010 that all pregnant women should be tested for smoking using carbon monoxide detectors, partly because 'some women find it difficult to say that they smoke because the pressure not to smoke during pregnancy is so intense.'. All women who smoke, or have stopped smoking within the last 2 weeks, or those with a CO reading of 7 ppm or above should be referred to NHS Stop Smoking Services.
Interventions
· the first-line interventions in pregnancy should be cognitive behaviour therapy, motivational interviewing or structured self-help and support from NHS Stop Smoking Services
· the evidence for the use of NRT in pregnancy is mixed but it is often used if the above measures failure. There is no evidence that it affects the child's birthweight. Pregnant women should remove the patches before going to bed
· as mentioned above, varenicline and bupropion are contraindicated
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Klebsiella
Klebsiella pneumoniae is a Gram-negative rod that is part of the normal gut flora. It can cause a number of infections in humans including pneumonia (typically following aspiration) and urinary tract infections.
Features of Klebsiella pneumonia
· more common in alcoholic and diabetics
· may occur following aspiration
· 'red-currant jelly' sputum
· often affects upper lobes
Prognosis
· commonly causes lung abscess formation and empyema
· mortality is 30-50%
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A human neutrophil interacting with Klebsiella pneumoniae (pink), a multidrug-resistant bacterium that causes severe hospital infections. Credit: NIAID
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Lung cancer: small cell
Features
· usually central
· arise from APUD* cells
· associated with ectopic ADH, ACTH secretion
· ADH → hyponatraemia
· ACTH → Cushing's syndrome
· ACTH secretion can cause bilateral adrenal hyperplasia, the high levels of cortisol can lead to hypokalaemic alkalosis
· Lambert-Eaton syndrome: antibodies to voltage gated calcium channels causing myasthenic like syndrome
Management
· usually metastatic disease by time of diagnosis
· patients with very early stage disease (T1-2a, N0, M0) are now considered for surgery. NICE support this approach in their 2011 guidelines
· however, most patients with limited disease receive a combination of chemotherapy and radiotherapy
· patients with more extensive disease are offered palliative chemotherapy
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| © Image used on license from Radiopaedia | |
CT scan showing small cell lung cancer with multiple pulmonary nodules and extensive mediastinal nodal metastases.
*an acronym for
· Amine - high amine content
· Precursor Uptake - high uptake of amine precursors
· Decarboxylase - high content of the enzyme decarboxylase
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Tension pneumothorax
Key points
· May occur following thoracic trauma when a lung parenchymal flap is created.
· This acts as a one way valve and allows pressure to rise.
· The trachea shifts and hyper-resonance is apparent on the affected side.
· Treatment is with needle decompression and chest tube insertion.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Acute respiratory distress syndrome
Acute respiratory distress syndrome (ARDS) is caused by the increased permeability of alveolar capillaries leading to fluid accumulation in the alveoli, i.e. non-cardiogenic pulmonary oedema. It is a serious condition that has a mortality of around 40% and is associated with significant morbidity in those who survive.
Causes
· infection: sepsis, pneumonia
· massive blood transfusion
· trauma
· smoke inhalation
· acute pancreatitis
· cardio-pulmonary bypass
Clinical features are typically of an acute onset and severe:
· dyspnoea
· elevated respiratory rate
· bilateral lung crackles
· low oxygen saturations
A chest x-ray and arterial blood gases are the key investigations.
Criteria (American-European Consensus Conference)
· acute onset (within 1 week of a known risk factor)
· pulmonary oedema: bilateral infiltrates on chest x-ray ('not fully explained by effusions, lobar/lung collapse or nodules)
· non-cardiogenic (pulmonary artery wedge pressure needed if doubt)
· pO2/FiO2 < 40kPa (200 mmHg)
Management
· due to the severity of the condition patients are generally managed in ITU
· oxygenation/ventilation to treat the hypoxaemia
· general organ support e.g. vasopressors as needed
· treatment of the underlying cause e.g. antibiotics for sepsis
· certain strategies such as prone positioning and muscle relaxation have been shown to improve outcome in ARDS
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Atelectasis
Atelectasis is a common postoperative complication in which basal alveolar collapse can lead to respiratory difficulty. It is caused when airways become obstructed by bronchial secretions.
Features
· it should be suspected in the presentation of dyspnoea and hypoxaemia around 72 hours postoperatively
Management
· positioning the patient upright
· chest physiotherapy: breathing exercises
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Bilateral hilar lymphadenopathy
The most common causes of bilateral hilar lymphadenopathy are sarcoidosis and tuberculosis.
Other causes include:
· lymphoma/other malignancy
· pneumoconiosis e.g. berylliosis
· fungi e.g. histoplasmosis, coccidioidomycosis
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Chest x-ray: pulmonary oedema
Features of pulmonary oedema on a chest x-ray may include:
· interstitial oedema
· bat's wing appearance
· upper lobe diversion (increased blood flow to the superior parts of the lung)
· Kerley B lines
· pleural effusion
· cardiomegaly may be seen if there is cardiogenic cause
| | |
| © Image used on license from Radiopaedia | |
Kerley A lines (orange arrows), Kerley B lines (blue arrows) and Kerley C lines (green arrows) are all seen, and all represent essentially the same thing; expansion of the interstitial space by fluid.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
COPD: long-term oxygen therapy
The 2018 NICE guidelines on COPD clearly define which patients should be assessed for and offered long-term oxygen therapy (LTOT). Patients who receive LTOT should breathe supplementary oxygen for at least 15 hours a day. Oxygen concentrators are used to provide a fixed supply for LTOT.
Assess patients if any of the following:
· very severe airflow obstruction (FEV1 < 30% predicted). Assessment should be 'considered' for patients with severe airflow obstruction (FEV1 30-49% predicted)
· cyanosis
· polycythaemia
· peripheral oedema
· raised jugular venous pressure
· oxygen saturations less than or equal to 92% on room air
Assessment is done by measuring arterial blood gases on 2 occasions at least 3 weeks apart in patients with stable COPD on optimal management.
Offer LTOT to patients with a pO2 of < 7.3 kPa or to those with a pO2 of 7.3 - 8 kPa and one of the following:
· secondary polycythaemia
· peripheral oedema
· pulmonary hypertension
In terms of smoking, NICE advise the following:
· do not offer LTOT to people who continue to smoke despite being offered smoking cessation advice and treatment, and referral to specialist stop smoking services.
NICE suggest that a structured risk assessment is carried out before offering LTOT, including:
· the risks of falls from tripping over the equipment
· the risks of burns and fires, and the increased risk of these for people who live in homes where someone smokes (including e‑cigarettes)
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Inhaler technique
The following inhaler technique guideline is for metered-dose inhalers (source: Asthma.org.uk, a resource recommended to patients by the British Thoracic Society)
1. Remove cap and shake
2. Breathe out gently
3. Put mouthpiece in mouth and as you begin to breathe in, which should be slow and deep, press canister down and continue to inhale steadily and deeply
4. Hold breath for 10 seconds, or as long as is comfortable
5. For a second dose wait for approximately 30 seconds before repeating steps 1-4.
Only use the device for the number of doses on the label, then start a new inhaler.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Lung cancer: features
Features
· persistent cough
· haemoptysis
· dyspnoea
· chest pain
· weight loss and anorexia
· hoarseness
o seen with Pancoast tumours pressing on the recurrent laryngeal nerve
· superior vena cava syndrome
Examination findings
· a fixed, monophonic wheeze may be noted
· supraclavicular lymphadenopathy or persistent cervical lymphadenopathy
· clubbing
Paraneoplastic features:
| Small cell | Squamous cell | Adenocarcinoma |
| · ADH · ACTH - not typical, hypertension, hyperglycaemia, hypokalaemia, alkalosis and muscle weakness are more common than buffalo hump etc · Lambert-Eaton syndrome | · parathyroid hormone-related protein (PTH-rp) secretion causing hypercalcaemia · clubbing · hypertrophic pulmonary osteoarthropathy (HPOA) · hyperthyroidism due to ectopic TSH | · gynaecomastia · hypertrophic pulmonary osteoarthropathy (HPOA) |
Complications
· hoarseness
· stridor
A thrombocytosis may be noted on bloods.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Lung fibrosis
It is important in the exam to be able to differentiate between conditions causing predominately upper or lower zone fibrosis. It should be noted that the more common causes (idiopathic pulmonary fibrosis, drugs) tend to affect the lower zones
Fibrosis predominately affecting the upper zones
· hypersensitivity pneumonitis (also known as extrinsic allergic alveolitis)
· coal worker's pneumoconiosis/progressive massive fibrosis
· silicosis
· sarcoidosis
· ankylosing spondylitis (rare)
· histiocytosis
· tuberculosis
Fibrosis predominately affecting the lower zones
· idiopathic pulmonary fibrosis
· most connective tissue disorders (except ankylosing spondylitis) e.g. SLE
· drug-induced: amiodarone, bleomycin, methotrexate
· asbestosis
Acronym for causes of upper zone fibrosis:
CHARTS
· C - Coal worker's pneumoconiosis
· H - Histiocytosis/ hypersensitivity pneumonitis
· A - Ankylosing spondylitis
· R - Radiation
· T - Tuberculosis
· S - Silicosis/sarcoidosis
| | |
| © Image used on license from Radiopaedia | |
CT scan showing advanced pulmonary fibrosis including 'honeycombing'
From <https://www.passmedicine
| Massive fibrotic masses in the upper zones | progressive massive fibrosis due to progression of coal workers’ pneumoconiosis |
| Reticulo-nodular opacities in the lower zones | pulmonary fibrosis |
| Bilateral pleural effusions | cardiac failure |
| Multiple bullae in the upper zones | emphysematous changes |
From <https://mle.ncl.ac.uk/cases/page/18128/>
progressive dyspnoea secondary to silicosis caused by his occupational work with ceramics. CXR would show nodular pattern in the upper and mid-zones and egg-shell calcification of the hilar nodes.
From <https://mle.ncl.ac.uk/cases/page/18128/>
h
24 December 2020
17:52
Transfer factor
The transfer factor describes the rate at which a gas will diffuse from alveoli into blood. Carbon monoxide is used to test the rate of diffusion. Results may be given as the total gas transfer (TLCO) or that corrected for lung volume (transfer coefficient, KCO)
| Causes of a raised TLCO · asthma · pulmonary haemorrhage (Wegener's, Goodpasture's) · left-to-right cardiac shunts · polycythaemia · hyperkinetic states · male gender, exercise | Causes of a lower TLCO · pulmonary fibrosis · pneumonia · pulmonary emboli · pulmonary oedema · emphysema · anaemia · low cardiac output |
KCO also tends to increase with age. Some conditions may cause an increased KCO with a normal or reduced TLCO
· pneumonectomy/lobectomy
· scoliosis/kyphosis
· neuromuscular weakness
· ankylosis of costovertebral joints e.g. ankylosing spondylitis
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Asbestos and the lung
Asbestos can cause a variety of lung disease from benign pleural plaques to mesothelioma.
Pleural plaques
Pleural plaques are benign and do not undergo malignant change. They are the most common form of asbestos related lung disease and generally occur after a latent period of 20-40 years.
Pleural thickening
Asbestos exposure may cause diffuse pleural thickening in a similar pattern to that seen following an empyema or haemothorax. The underlying pathophysiology is not fully understood.
Asbestosis
The severity of asbestosis is related to the length of exposure. This is in contrast to mesothelioma where even very limited exposure can cause disease. The latent period is typically 15-30 years. Asbestosis typically causes lower lobe fibrosis. As with other forms of lung fibrosis the most common symptoms are shortness-of-breath and reduced exercise tolerance.
Mesothelioma
Mesothelioma is a malignant disease of the pleura. Crocidolite (blue) asbestos is the most dangerous form.
Possible features
· progressive shortness-of-breath
· chest pain
· pleural effusion
Patients are usually offered palliative chemotherapy and there is also a limited role for surgery and radiotherapy. Unfortunately the prognosis is very poor, with a median survival from diagnosis of 8-14 months.
Lung cancer
Asbestos exposure is a risk factor for lung cancer and also has a synergistic effect with cigarette smoke.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:52
Chest drain: anatomy of insertion
There are a number of different indications for chest drain insertion. In general terms large bore chest drains are preferred for trauma and haemothorax drainage. Smaller diameter chest drains can be used for pneumothorax or pleural effusion drainage.
Insertion can be performed either using anatomical guidance or through ultrasound guidance. In the exam, the anatomical method is usually tested.
It is advised that chest drains are placed in the 'safe triangle'. The triangle is located in the mid axillary line of the 5th intercostal space. It is bordered by:
Anterior edge latissimus dorsi, the lateral border of pectoralis major, a line superior to the horizontal level of the nipple, and the apex below the axilla.
Another triangle is situated behind the scapula. It is bounded above by the trapezius, below by the latissimus dorsi, and laterally by the vertebral border of the scapula; the floor is partly formed by the rhomboid major. If the scapula is drawn forward by folding the arms across the chest, and the trunk bent forward, parts of the sixth and seventh ribs and the interspace between them become subcutaneous and available for auscultation. The space is therefore known as the triangle of auscultation.
References
Prof Harold Ellis. The applied anatomy of chest drains insertions. British Journal of hospital medicine 2007; (68): 44-45.
Laws D, Neville E, Duffy J. BTS guidelines for insertion of chest drains. Thorax, 2003; (58): 53-59.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Chest x-ray: lobar collapse
Common causes of lobar collapse include:
· lung cancer (the most common cause in older adults)
· asthma (due to mucous plugging)
· foreign body
The general signs of lobar collapse on a chest x-ray are as follows:
· tracheal deviation towards the side of the collapse
· mediastinal shift towards the side of the collapse
· elevation of the hemidiaphragm
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Chest x-ray: lung metastases
Lung metastases are seen with a wide variety of cancers including:
· breast cancer
· colorectal cancer
· renal cell cancer
· bladder cancer
· prostate cancer
Multiple, round well-defined lung secondaries are often referred to as 'cannonball metastases'. They are most commonly seen with renal cell cancer but may also occur secondary to choriocarcinoma and prostate cancer.
Calcification in lung metastases is uncommon except in the case of chondrosarcoma or osteosarcoma.
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| © Image used on license from Radiopaedia | |
Chest x-ray showing cannonball metastases secondary to renal cell cancer. Multiple well defined nodules are noted distributed in both lung fields
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Chest x-ray: nasogastric tube position
Chest x-rays are commonly ordered to check the position of nasogastric (NG) tubes. It is important to identify that the end of the tube is below the diaphragm in the stomach. Failure to recognise that a NG tube is not correctly positioned can have serious consequences for a patient including aspiration pneumonia and death. For this reason many hospitals now require a radiologist to report on these x-rays before the NG tube can be used.
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| © Image used on license from Radiopaedia | |
The NG tube tip is satisfactorily sited in a sub-diaphragmatic position.
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| © Image used on license from Radiopaedia | |
The NG tube tip is located in the right lower lobe.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Coal workers' pneumoconiosis
Coal worker’s pneumoconiosis*, sometimes referred to as ‘black lung disease’, is an occupational lung disease caused by long term exposure to coal dust particles. It is most commonly experienced by those who have been involved in the coal mining industry and severity is linked to the extent of exposure. Often there is a long lead time between the first exposure and the development of the disease.
Epidemiology:
· Prevalence is higher in populations with higher levels of exposure – e.g. areas with large coal mining industries.
· Most individuals are male due to their prevalence in the coal mining industry.
· Coal worker’s pneumoconiosis makes up around 7% of all Pneumoconiosis.
· Diagnosis is usually 15-20 years after initial exposure to the coal dust.
Pathophysiology:
· Coal dust (2-5 μm in size) is inhaled and enters the lungs.
· The dust reaches the terminal bronchioles and there it is engulfed by alveolar and interstitial macrophages.
· The dust particles are then moved by the macrophages via the mucociliary elevator and removed from the body as mucus.
· In coal miners who are exposed over many years, the system is overwhelmed and the macrophages begin to accumulate in the alveoli, which starts an immune response, causing damage to the lung tissue.
Exposure to coal dust can lead to one of two presentations:
Simple pneumoconiosis:
· Is the commonest type of pneumoconiosis.
· Patients are often asymptomatic.
· Its presence increases the risk of lung diseases such as COPD.
· Simple pneumoconiosis may lead to Progressive Massive Fibrosis (PMF), occurring in around 30% of those with stage 3 grading.
Staging
· The disease is graded on the appearance of the chest X-ray using categories outlined by the International Labour Office:
· Category 1: some opacities but normal lung markings visible
· Category 2: large number of opacities but normal lung markings visible
· Category 3: large number of opacities with normal lung not visible
Progressive Massive Fibrosis
· Dust exposure causes patients to develop round fibrotic masses which can be several centimetres in diameter.
· These are most commonly in the upper lobes.
· The exact pathogenesis is not known.
· Patients are often symptomatic and have both breathlessness on exertion and cough, some may have black sputum.
· Lung function testing shows a mixed obstructive/restrictive picture.
Investigations:
· Chest x-ray: upper zone fibrosis
· Spirometry: restrictive lung function tests - a normal or slightly reduced FEV1 and a reduced FVC
Management:
· Avoid exposure to coal dust and other respiratory irritants (e.g. Smoking).
· Manage symptoms of chronic bronchitis
· Patients may be eligible for compensation via the Industrial Injuries Act.
*Pneumoconiosis = accumulation of dust in the lungs and the response of the bodily tissue to its presence, most commonly used in relation to coal worker’s pneumoconiosis.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
COPD: features
Chronic obstructive pulmonary disease (COPD) is one of the most common diagnoses encountered in medical practice. COPD is an umbrella term encompassing the older terms chronic bronchitis and emphysema. In the vast majority of cases, COPD is caused by smoking. Some patients with more mild disease may just need to use a bronchodilator occasionally whereas other patients may have several hospital admissions a year secondary to infective exacerbations.
Features
· cough: often productive
· dyspnoea
· wheeze
· in severe cases, right-sided heart failure may develop resulting in peripheral oedema
The following investigations are recommended in patients with suspected COPD:
· post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%
· chest x-ray
o hyperinflation
o bullae: if large, may sometimes mimic a pneumothorax
o flat hemidiaphragm
o also important to exclude lung cancer
· full blood count: exclude secondary polycythaemia
· body mass index (BMI) calculation
The severity of COPD is categorised using the FEV1*:
| Post-bronchodilator FEV1/FVC | FEV1 (of predicted) | Severity |
| < 0.7 | > 80% | Stage 1 - Mild** |
| < 0.7 | 50-79% | Stage 2 - Moderate |
| < 0.7 | 30-49% | Stage 3 - Severe |
| < 0.7 | < 30% | Stage 4 - Very severe |
Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
*note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as Stage 1 - mild
**symptoms should be present to diagnose COPD in these patients
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Disorders of acid - base balance
The acid-base normogram below shows how the various disorders may be categorised
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| Image sourced from Wikipedia | |
Metabolic acidosis
· This is the most common surgical acid - base disorder.
· Reduction in plasma bicarbonate levels.
· Two mechanisms:
1. Gain of strong acid (e.g. diabetic ketoacidosis)
2. Loss of base (e.g. from bowel in diarrhoea)
- Classified according to the anion gap, this can be calculated by:
(Na+ + K+) - (Cl- + HCO3-).
- If a question supplies the chloride level then this is often a clue that the anion gap should be calculated. The normal range = 10-18 mmol/L
Normal anion gap ( = hyperchloraemic metabolic acidosis)
· Gastrointestinal bicarbonate loss: diarrhoea, ureterosigmoidostomy, fistula
· Renal tubular acidosis
· Drugs: e.g. acetazolamide
· Ammonium chloride injection
· Addison's disease
Raised anion gap
· Lactate: shock, hypoxia
· Ketones: diabetic ketoacidosis, alcohol
· Urate: renal failure
· Acid poisoning: salicylates, methanol
Metabolic acidosis secondary to high lactate levels may be subdivided into two types:
· Lactic acidosis type A: (Perfusion disorders e.g.shock, hypoxia, burns)
· Lactic acidosis type B: (Metabolic e.g. metformin toxicity)
Metabolic alkalosis
· Usually caused by a rise in plasma bicarbonate levels.
· Rise of bicarbonate above 24 mmol/L will typically result in renal excretion of excess bicarbonate.
· Caused by a loss of hydrogen ions or a gain of bicarbonate. It is due mainly to problems of the kidney or gastrointestinal tract
Causes
· Vomiting / aspiration (e.g. Peptic ulcer leading to pyloric stenosis, nasogastric suction)
· Diuretics
· Liquorice, carbenoxolone
· Hypokalaemia
· Primary hyperaldosteronism
· Cushing's syndrome
· Bartter's syndrome
· Congenital adrenal hyperplasia
Mechanism of metabolic alkalosis
· Activation of renin-angiotensin II-aldosterone (RAA) system is a key factor
· Aldosterone causes reabsorption of Na+ in exchange for H+ in the distal convoluted tubule
· ECF depletion (vomiting, diuretics) → Na+ and Cl- loss → activation of RAA system → raised aldosterone levels
· In hypokalaemia, K+ shift from cells → ECF, alkalosis is caused by shift of H+ into cells to maintain neutrality
Respiratory acidosis
· Rise in carbon dioxide levels usually as a result of alveolar hypoventilation
· Renal compensation may occur leading to Compensated respiratory acidosis
Causes
· COPD
· Decompensation in other respiratory conditions e.g. Life-threatening asthma / pulmonary oedema
· Sedative drugs: benzodiazepines, opiate overdose
Respiratory alkalosis
· Hyperventilation resulting in excess loss of carbon dioxide
· This will result in increasing pH
Causes
· Psychogenic: anxiety leading to hyperventilation
· Hypoxia causing a subsequent hyperventilation: pulmonary embolism, high altitude
· Early salicylate poisoning*
· CNS stimulation: stroke, subarachnoid haemorrhage, encephalitis
· Pregnancy
*Salicylate overdose leads to a mixed respiratory alkalosis and metabolic acidosis. Early stimulation of the respiratory centre leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Eosinophilic granulomatosis with polyangiitis (Churg-Strauss syndrome)
Eosinophilic granulomatosis with polyangiitis (EGPA) is now the preferred term for Churg-Strauss syndrome. It is an ANCA associated small-medium vessel vasculitis.
Features
· asthma
· blood eosinophilia (e.g. > 10%)
· paranasal sinusitis
· mononeuritis multiplex
· pANCA positive in 60%
| | |
| |
Comparison of granulomatosis with polyangiitis and Churg-Strauss syndrome
Leukotriene receptor antagonists may precipitate the disease.
From <https://www.passmedicine.com/review/textbook.php?s=#>
Churg-Strauss syndrome - positive pANCA serology
Churg-Strauss disease is associated with pANCA.
There are three stages to the presentation of Churg-Strauss disease.
The initial phase is characterised by allergy with many patients having a history of asthma or allergic rhinitis. This inflammation of the nasal passages can lead to the development of nasal polyps.
The second phase is eosinophilia
The third stage is the vasculitis itself which affects small and medium-sized blood vessels and therefore resulting in damage to many organs. Given this patient's kidney failure, it appears to be affecting his renal blood supply.
Other common affected organs are the lungs, the digestive tract and most dangerously, the heart.
The features in the history that tell us it is Churg-Strauss syndrome are the history of asthma and recurrent nasal polyps (the first stage), eosinophilia (the second stage) and impaired kidney function and petechial rash (the third stage).
24 December 2020
17:53
Granulomatosis with polyangiitis (Wegener's granulomatosis)
Granulomatosis with polyangiitis is now the preferred term for Wegener's granulomatosis. It is an autoimmune condition associated with a necrotizing granulomatous vasculitis, affecting both the upper and lower respiratory tract as well as the kidneys.
Features
· upper respiratory tract: epistaxis, sinusitis, nasal crusting
· lower respiratory tract: dyspnoea, haemoptysis
· rapidly progressive glomerulonephritis ('pauci-immune', 80% of patients)
· saddle-shape nose deformity
· also: vasculitic rash, eye involvement (e.g. proptosis), cranial nerve lesions
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Comparison of granulomatosis with polyangiitis and Churg-Strauss syndrome
Investigations
· cANCA positive in > 90%, pANCA positive in 25%
· chest x-ray: wide variety of presentations, including cavitating lesions
· renal biopsy: epithelial crescents in Bowman's capsule
Management
· steroids
· cyclophosphamide (90% response)
· plasma exchange
· median survival = 8-9 years
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Lung cancer: types
Lung cancer is initially classified histologically as being either small cell lung cancer (SCLC) or non-small cell lung cancer (NSCLC) due to the different features, management and prognosis see in the two groups.
SCLC accounts for around 15% of cases and generally carries a worse prognosis.
NSCLC can be broken down into
· adenocarcinoma
o this is now the most common type of lung cancer
o often seen in non-smokers
· squamous
· large cell
· alveolar cell carcinoma: not related to smoking, ++sputum
· bronchial adenoma: mostly carcinoid
Differentiating between NSCLC is now more important than before due to the different drugs available treat the subtypes.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Mesothelioma
Mesothelioma is a cancer of the mesothelial layer of the pleural cavity that is strongly associated with asbestos exposure. In a small percentage of cases, other mesothelial layers such as those in the abdomen may be affected.
Features
· Dyspnoea, weight loss, chest wall pain
· Clubbing
· 30% present as painless pleural effusion
· Only 20% have pre-existing asbestosis
· History of asbestos exposure in 85-90%, latent period of 30-40 years
Basics
· Malignancy of mesothelial cells of pleura
· Metastases to contralateral lung and peritoneum
· Right lung affected more often than left
Investigation/diagnosis
· suspicion is normally raised by a chest x-ray showing either a pleural effusion or pleural thickening
· the next step is normally a pleural CT
· if a pleural effusion is present fluid should be sent for MC&S, biochemistry and cytology (but cytology is only helpful in 20-30% of cases)
· local anaesthetic thoracoscopy is increasingly used to investigate cytology negative exudative effusions as it has a high diagnostic yield (around 95%)
· if an area of pleural nodularity is seen on CT then an image-guided pleural biopsy may be used
Management
· Symptomatic
· Industrial compensation
· Chemotherapy, Surgery if operable
· Prognosis poor, median survival 12 months
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Respiratory acidosis
Respiratory acidosis may be caused by a number of conditions:
· COPD
· decompensation in other respiratory conditions e.g. life-threatening asthma / pulmonary oedema
· neuromuscular disease
· obesity hypoventilation syndrome
· sedative drugs: benzodiazepines, opiate overdose
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Sarcoidosis: management
Sarcoidosis is a multisystem disorder of unknown aetiology characterised by non-caseating granulomas. It is more common in young adults and in people of African descent.
Indications for steroids
· patients with chest x-ray stage 2 or 3 disease who are symptomatic. Patients with asymptomatic and stable stage 2 or 3 disease who have only mildly abnormal lung function do not require treatment
· hypercalcaemia
· eye, heart or neuro involvement
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Adult respiratory distress syndrome
Defined as an acute condition characterized by bilateral pulmonary infiltrates and severe hypoxemia (PaO2/FiO2 ratio < 200) in the absence of evidence for cardiogenic pulmonary oedema (clinically or pulmonary capillary wedge pressure of less than 18 mm Hg).
In is subdivided into two stages. Early stages consist of an exudative phase of injury with associated oedema. The later stage is one of repair and consists of fibroproliferative changes. Subsequent scarring may result in poor lung function.
Causes
· Sepsis
· Direct lung injury
· Trauma
· Acute pancreatitis
· Long bone fracture or multiple fractures (through fat embolism)
· Head injury (causes sympathetic nervous stimulation which leads to acute pulmonary hypertension)
Clinical features
· Acute dyspnoea and hypoxaemia hours/days after event
· Multi organ failure
· Rising ventilatory pressures
Management
· Treat the underlying cause
· Antibiotics (if signs of sepsis)
· Negative fluid balance i.e. Diuretics
· Recruitment manoeuvres such as prone ventilation, use of positive end expiratory pressure
· Mechanical ventilation strategy using low tidal volumes, as conventional tidal volumes may cause lung injury (only treatment found to improve survival rates)
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Altitude related disorders
There are three main types of altitude related disorders: acute mountain sickness (AMS), which may progress to high altitude pulmonary edema (HAPE) or high altitude cerebral edema (HACE). All three conditions are due to the chronic hypobaric hypoxia which develops at high altitudes
Acute mountain sickness is generally a self-limiting condition. Features of AMS start to occur above 2,500 - 3,000m, developing gradually over 6-12 hours and potentially last a number of days:
· headache
· nausea
· fatigue
Prevention and treatment of AMS
· the risk of AMS may actually be positively correlated to physical fitness
· gain altitude at no more than 500 m per day
· acetazolamide (a carbonic anhydrase inhibitor) is widely used to prevent AMS and has a supporting evidence base
· treatment: descent
A minority of people above 4,000m go onto develop high altitude pulmonary oedema (HAPE) or high altitude cerebral oedema (HACE), potentially fatal conditions
· HAPE presents with classical pulmonary oedema features
· HACE presents with headache, ataxia, papilloedema
Management of HACE
· descent
· dexamethasone
Management of HAPE
· descent
· nifedipine, dexamethasone, acetazolamide, phosphodiesterase type V inhibitors*
· oxygen if available
*the relative merits of these different treatments has only been studied in small trials. All seem to work by reducing systolic pulmonary artery pressure
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Asthma: occupational
Patients may either present with concerns that chemicals at work are worsening their asthma or you may notice in the history that symptoms seem better at weekends / when away from work.
Exposure to the following chemicals is associated with occupational asthma:
· isocyanates - the most common cause. Example occupations include spray painting and foam moulding using adhesives
· platinum salts
· soldering flux resin
· glutaraldehyde
· flour
· epoxy resins
· proteolytic enzymes
Serial measurements of peak expiratory flow are recommended at work and away from work.
Referral should be made to a respiratory specialist for patients with suspected occupational asthma.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Asthma: stepping down treatment
The British Thoracic Society (BTS) guidelines recommend that we should consider stepping down treatment every 3 months or so. The guidelines don't advocate a strict move from say step 3 to step 2 but advise us to take into account duration of treatment, side-effects and patient preference.
When reducing the dose of inhaled steroids the BTS advise us to do this by 25-50% at a time.
Clearly patients with stable asthma may only have a formal review on an annual basis but it is likely that if a patient has recently had an escalation of asthma treatment they would be reviewed on a more frequent basis.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Bronchiectasis: causes
Bronchiectasis describes a permanent dilatation of the airways secondary to chronic infection or inflammation. There are a wide variety of causes are listed below:
Causes
· post-infective: tuberculosis, measles, pertussis, pneumonia
· cystic fibrosis
· bronchial obstruction e.g. lung cancer/foreign body
· immune deficiency: selective IgA, hypogammaglobulinaemia
· allergic bronchopulmonary aspergillosis (ABPA)
· ciliary dyskinetic syndromes: Kartagener's syndrome, Young's syndrome
· yellow nail syndrome
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| © Image used on license from Radiopaedia | |
Chest x-ray showing tramlines, most prominent in the left lower zone
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| © Image used on license from Radiopaedia | |
CT chest showing widespread tram-track and signet ring signs
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Bronchiectasis: management
Bronchiectasis describes a permanent dilatation of the airways secondary to chronic infection or inflammation. After assessing for treatable causes (e.g. immune deficiency) management is as follows:
· physical training (e.g. inspiratory muscle training) - has a good evidence base for patients with non-cystic fibrosis bronchiectasis
· postural drainage
· antibiotics for exacerbations + long-term rotating antibiotics in severe cases
· bronchodilators in selected cases
· immunisations
· surgery in selected cases (e.g. Localised disease)
Most common organisms isolated from patients with bronchiectasis:
· Haemophilus influenzae (most common)
· Pseudomonas aeruginosa
· Klebsiella spp.
· Streptococcus pneumoniae
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Chest x-ray: cavitating lung lesion
Differential
· abscess (Staph aureus, Klebsiella and Pseudomonas)
· squamous cell lung cancer
· tuberculosis
· Wegener's granulomatosis
· pulmonary embolism
· rheumatoid arthritis
· aspergillosis, histoplasmosis, coccidioidomycosis
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Chest x-ray: mediastinal widening
Probably the most common cause of mediastinal widening on a chest x-ray are technical factors such as patient rotation.
Causes of actual mediastinal widening include:
· vascular problems: thoracic aortic aneurysm
· lymphoma
· retrosternal goitre
· teratoma
· tumours of the thymus
A lateral view may help to determine whether the mass is anterior or posterior but nowadays a CT would be performed if there was any doubt about the cause.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Clubbing
The causes of clubbing may be divided into cardiac, respiratory and other
Cardiac causes
· cyanotic congenital heart disease (Fallot's, TGA)
· bacterial endocarditis
· atrial myxoma
Respiratory causes
· lung cancer
· pyogenic conditions: cystic fibrosis, bronchiectasis, abscess, empyema
· tuberculosis
· asbestosis, mesothelioma
· fibrosing alveolitis
Other causes
· Crohn's, to a lesser extent UC
· cirrhosis, primary biliary cirrhosis
· Graves' disease (thyroid acropachy)
· rare: Whipple's disease
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:53
Extrinsic allergic alveolitis
Extrinsic allergic alveolitis (EAA, also known as hypersensitivity pneumonitis) is a condition caused by hypersensitivity induced lung damage due to a variety of inhaled organic particles. It is thought to be largely caused by immune-complex mediated tissue damage (type III hypersensitivity) although delayed hypersensitivity (type IV) is also thought to play a role in EAA, especially in the chronic phase.
Examples
· bird fanciers' lung: avian proteins from bird droppings
· farmers lung: spores of Saccharopolyspora rectivirgula from wet hay (formerly Micropolyspora faeni)
· malt workers' lung: Aspergillus clavatus
· mushroom workers' lung: thermophilic actinomycetes*
Presentation
· acute (occurs 4-8 hrs after exposure)
o dyspnoea
o dry cough
o fever
· chronic (occurs weeks-months after exposure)
o lethargy
o dyspnoea
o productive cough
o anorexia and weight loss
Investigation
· imaging: upper/mid-zone fibrosis
· bronchoalveolar lavage: lymphocytosis
· serologic assays for specific IgG antibodies
· blood: NO eosinophilia
Management
· avoid precipitating factors
· oral glucocorticoids
*here the terminology is slightly confusing as thermophilic actinomycetes is an umbrella term covering strains such as Micropolyspora faeni
| | |
| © Image used on license from Radiopaedia | |
| | |
| © Image used on license from Radiopaedia | |
Chest x-ray and CT scan from a middle-aged woman who presented with dyspnoea. The CT demonstrates multuple centrilobular ground glass nodules consistent with hypersensitivity pneumonitis
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Haemoptysis
The table below lists the main characteristics of the most important causes of haemoptysis:
| Diagnosis | Notes |
| Lung cancer | History of smoking Symptoms of malignancy: weight loss, anorexia |
| Pulmonary oedema | Dyspnoea Bibasal crackles and S3 are the most reliable signs |
| Tuberculosis | Fever, night sweats, anorexia, weight loss |
| Pulmonary embolism | Pleuritic chest pain Tachycardia, tachypnoea |
| Lower respiratory tract infection | Usually acute history of purulent cough |
| Bronchiectasis | Usually long history of cough and daily purulent sputum production |
| Mitral stenosis | Dyspnoea Atrial fibrillation Malar flush on cheeks Mid-diastolic murmur |
| Aspergilloma | Often past history of tuberculosis. Haemoptysis may be severe Chest x-ray shows rounded opacity |
| Granulomatosis with polyangiitis | Upper respiratory tract: epistaxis, sinusitis, nasal crusting Lower respiratory tract: dyspnoea, haemoptysis Glomerulonephritis Saddle-shape nose deformity |
| Goodpasture's syndrome | Haemoptysis Systemically unwell: fever, nausea Glomerulonephritis |
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Lung cancer: investigation
Chest x-ray
· this is often the first investigation done in patients with suspected lung cancer
· in around 10% of patients subsequently diagnosed with lung cancer the chest x-ray was reported as normal
CT
· is the investigation of choice to investigate suspected lung cancer
Bronchoscopy
· this allows a biopsy to be taken to obtain a histological diagnosis sometimes aided by endobronchial ultrasound
PET scanning
· is typically done in non-small cell lung cancer to establish eligibility for curative treatment
· uses 18-fluorodeoxygenase which is preferentially taken up by neoplastic tissue
· has been shown to improve diagnostic sensitivity of both local and distant metastasis spread in non-small cell lung cancer
Bloods
· raised platelets may be seen
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Lung cancer: non-small cell management
Management
· only 20% suitable for surgery
· mediastinoscopy performed prior to surgery as CT does not always show mediastinal lymph node involvement
· curative or palliative radiotherapy
· poor response to chemotherapy
Surgery contraindications
· assess general health
· stage IIIb or IV (i.e. metastases present)
· FEV1 < 1.5 litres is considered a general cut-off point*
· malignant pleural effusion
· tumour near hilum
· vocal cord paralysis
· SVC obstruction
* However if FEV1 < 1.5 for lobectomy or < 2.0 for pneumonectomy then some authorities advocate further lung function tests as operations may still go ahead based on the results
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Lung cancer: referral
The 2015 NICE cancer referral guidelines gave the following advice:
Refer people using a suspected cancer pathway referral (for an appointment within 2 weeks) for lung cancer if they:
· have chest x-ray findings that suggest lung cancer
· are aged 40 and over with unexplained haemoptysis
Offer an urgent chest x-ray (to be performed within 2 weeks) to assess for lung cancer in people aged 40 and over if they have 2 or more of the following unexplained symptoms, or if they have ever smoked and have 1 or more of the following unexplained symptoms:
· cough
· fatigue
· shortness of breath
· chest pain
· weight loss
· appetite loss
Consider an urgent chest x-ray (to be performed within 2 weeks) to assess for lung cancer in people aged 40 and over with any of the following:
· persistent or recurrent chest infection
· finger clubbing
· supraclavicular lymphadenopathy or persistent cervical lymphadenopathy
· chest signs consistent with lung cancer
· thrombocytosis
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Mediastinum
Region between the pulmonary cavities.
It is covered by the mediastinal pleura. It does not contain the lungs.
It extends from the thoracic inlet superiorly to the diaphragm inferiorly.
Mediastinal regions
· Superior mediastinum (between manubriosternal angle and T4/5)
· Middle mediastinum
· Posterior mediastinum
· Anterior mediastinum
| Region | Contents |
| Superior mediastinum | · Superior vena cava · Brachiocephalic veins · Arch of aorta · Thoracic duct · Trachea · Oesophagus · Thymus · Vagus nerve · Left recurrent laryngeal nerve · Phrenic nerve |
| Anterior mediastinum | · Thymic remnants · Lymph nodes · Fat |
| Middle mediastinum | · Pericardium · Heart · Aortic root · Arch of azygos vein · Main bronchi |
| Posterior mediastinum | · Oesophagus · Thoracic aorta · Azygos vein · Thoracic duct · Vagus nerve · Sympathetic nerve trunks · Splanchnic nerves |
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Pneumonia: a very basic introduction
Pneumonia is one of the most common presentations encountered in clinical practice. Strictly speaking it describes any inflammatory condition affecting the alveoli of the lungs, but in the vast majority of patients this is secondary to a bacterial infection.
Causes
As mentioned before, bacterial pneumonia is by far the most common type of pneumonia seen in clinical practice. Other infective causes include:
· viral
· fungal (e.g. Pneumocystis jiroveci)
The table below shows some of the organisms which can cause pneumonia
| Organism | Notes |
| Streptococcus pneumoniae (pneumococcus) | Accounts for 80% of cases Particularly associated with high fever, rapid onset and herpes labialis A vaccine to pneumococcus is available |
| Haemophilus influenzae | Particularly common in patients with COPD |
| Staphylococcus aureus | Often occurs in patient following influenza infection |
| Mycoplasma pneumoniae | One of the atypical pneumonias, which often present a dry cough and atypical chest signs/x-ray findings Autoimmune haemolytic anaemia and erythema multiforme may be seen |
| Legionella pneumophilia | Another one of the atypical pneumonias Hyponatraemia and lymphopenia common Classically seen secondary to infected air conditioning units |
| Klebsiella pneumoniae | Classically seen in alcoholics |
| Pneumocystis jiroveci | Typically seen in patients with HIV Presents with a dry cough, exercise-induced desaturations and the absence of chest signs |
Idiopathic interstitial pneumonia is a group of non-infective causes of pneumonia. Examples include cryptogenic organizing pneumonia which describes a form of bronchiolitis which may develop as a complication of rheumatoid arthritis or amiodarone therapy.
Community vs. hospital-acquired pneumonia
The majority of patients develop pneumonia within the community, i.e. outside of hospital and these patients are said to have community-acquired pneumonia (CAP). Patients who develop pneumonia within hospitals are said to have hospital-acquired pneumonia. The distinction is important as the causative organisms vary and hence first-line antibiotic guidelines are also different.
Symptoms and signs
Symptoms
· cough
· sputum
· dyspnoea
· chest pain: may be pleuritic
· fever
Signs
· signs of systemic inflammatory response: fever, tachycardia
· reduced oxygen saturations
· ausculatation: reduced breath sounds, bronchial breathing
Investigations
Chest x-ray
· the classical x-ray finding in pneumonia is consolidation
| | |
| © Image used on license from Radiopaedia | |
This film demonstrates classical signs of right upper lobe consolidation - abnormal opacity within the right upper lobe abutting the horizontal fissure. Note how the 'position' of the consolidation on the film (i.e. in the 'middle' of the lung) doesn't necessarily correlate with the lobe affected.
| | |
| © Image used on license from Radiopaedia | |
Here the consolidation is harder to spot. Look at the left heart border - it is normally well dermaracted with the lung. Here it is fuzzy - this is a classic sign of left lingula consolidation.
Bloods
· full blood count: would usually show a neutrophilia in bacterial infections
· urea and electrolytes: check for dehydration (remember the 'U' for urea in CURB-65, see below) and also other changes seen with some atypical pneumonias
· CRP: raised in response to infection
Arterial blood gases
· indicated if the oxygen saturations or low or the patient has pre-existing respiratory disease, for example COPD
Management
Patients with pneumonia require the following:
· antibiotics: to treat the underlying infection
· supportive care: for example oxygen therapy if the patients is hypoxaemic, intravenous fluids if the patient is hypotensive or shows signs of dehydration
The management of patients with community-acquired pneumonia is usually determined according to a risk stratification process using a scoring system called CURB-65.
The CURB-65 score is as follows:
| Criterion | Marker |
| C | Confusion (abbreviated mental test score <= 8/10) |
| U | Urea >7 mmol/L |
| R | Respiration rate >= 30/min |
| B | Blood pressure: systolic <= 90 mmHg and/or diastolic <= 60 mmHg |
| 65 | Aged >= 65 years |
Patients with a CURB-65 score of 0 should be managed in the community.
Patients with a CURB-65 score of 1 should have their Sa02 assessed which should be >92% to be safely managed in the community and a CXR performed. If the CXR shows bilateral/multilobar shadowing hospital admission is advised.
Patients with a CURB-65 score of 2 or more should be managed in hospital as this represents a severe community acquired pneumonia.
The CURB-65 score also correlates with an increased risk of mortality at 30 days with patients with a CURB-65 score of 4 approaching a 30% mortality rate at 30 days.
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Pneumothorax: features
Risk factors
· pre-existing lung disease: COPD, asthma, cystic fibrosis, lung cancer, Pneumocystis pneumonia
· connective tissue disease: Marfan's syndrome, rheumatoid arthritis
· ventilation, including non-invasive ventilation
· catamenial pneumothorax is the cause of 3-6% of spontaneous pneumothoraces occurring in menstruating women. It is thought to be caused by endometriosis within the thorax
Symptoms tend to come on suddenly. Features include:
· dyspnoea
· chest pain: often pleuritic
· sweating
· tachypnoea
· tachycardia
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Psittacosis
Psittacosis is infection caused by Chlamydia psittaci. The most common presentation is as a cause of atypical pneumonia. Psittacosis should be suspected in a combination of typical fever with a history of bird contact (reported in 84%) or a presentation with pneumonia and severe headache or organomegaly and failure to respond to penicillin-based antibiotics.
Epidemiology
· Psittacosis is present throughout the world, including the United Kingdom
· It is more common in young adults
Pathology
· Chlamydia psittaci is an obligate intracellular bacterium
· Transmission is typically from birds or bird secretions including urine and faeces, typically occurring after cleaning bird cages
· Many birds have been implicated in transmission, including pet birds and wild birds
· Transmission from other animals or humans is possible but very rare and no strong female or male predisposition has been noted
· It is rare; in the US there are roughly 10 cases reported annually
Patients typically present with a subacute onset of:
· Flu-like symptoms (90%): fever, headache and myalgia
· Respiratory symptoms (82%): dyspnoea, dry cough and chest pain
Signs:
· Chest: unilateral crepitations and vesicular breathing (common), evidence of pleural effusion (uncommon)
· Abdomen: hepatomegaly and splenomegaly (rare)
Investigations:
· Raised inflammatory markers
· Chest X-ray: consolidation (90%)
· Confirmation with serology (usually as part of atypical pneumonia screening)
Treatment:
· 1st-line: tetracyclines e.g. doxycycline
· 2nd-line: macrolides e.g. erythromycin
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Rheumatoid arthritis: respiratory manifestations
A variety of respiratory problems may be seen in patients with rheumatoid arthritis:
· pulmonary fibrosis
· pleural effusion
· pulmonary nodules
· bronchiolitis obliterans
· complications of drug therapy e.g. methotrexate pneumonitis
· pleurisy
· Caplan's syndrome - massive fibrotic nodules with occupational coal dust exposure
· infection (possibly atypical) secondary to immunosuppression
From <https://www.passmedicine.com/review/textbook.php?s=#>
24 December 2020
17:54
Shortness of breath: chronic
The table below gives characteristic features for conditions causing chronic shortness of breath (SOB):
| Chronic obstructive pulmonary disease | Seen invariably in smokers Chronic productive cough is typical Features of right heart failure may be seen |
| Heart failure | A history of ischaemic heart disease or hypertension may be present Orthopnoea and paroxysmal nocturnal dyspnoea are characteristic Bibasal crackles and a third heart sound (S3) are the most reliable features of left-sided failure Right heart failure causes peripheral oedema and a raised JVP |
| Asthma | Cough, wheeze and shortness of breath are typical Symptoms are often worse at night and may be precipitated by cold weather or exercise Associated with hay fever and eczema |
| Aortic stenosis | Chest pain, SOB and syncope seen in symptomatic patients An ejection systolic murmur radiating to the neck and narrow pulse pressure are found on examination |
| Recurrent pulmonary emboli | There may be a history of predisposing factors e.g. Malignancy Pleuritic chest pain and haemoptysis may be seen but symptoms are often vague Tachycardia and tachypnoea are common in the acute situation Symptoms of right heart failure may develop in severe cases |
| Lung cancer | Normally seen in smokers Haemoptysis, chronic cough or unresolving infection are common presentations Systemic symptoms e.g. Weight loss and anorexia |
| Pulmonary fibrosis | Progressive shortness of breath may be the only symptom Fine bibasal crackles are typical Spirometry shows a restrictive pattern |
| Bronchiectasis | Affected patients may produce large amounts of purulent sputum Patients may have a history of previous infections (e.g. Tuberculosis, measles), bronchial obstruction or ciliary dyskinetic syndromes e.g. Kartagener's syndrome |
| Anaemia | There may be a history of gastrointestinal symptoms Pallor may be seen on examination |
| Obesity | Obese patients tend to be more SOB due to the increased work of activity |
From <https://www.passmedicine.com/review/textbook.php?s=#>
21 December 2020
21:53
COPD: stable management
NICE updated its guidelines on the management of chronic obstructive pulmonary disease (COPD) in 2018.
General management
· >smoking cessation advice: including offering nicotine replacement therapy, varenicline or bupropion
· annual influenza vaccination
· one-off pneumococcal vaccination
· pulmonary rehabilitation to all people who view themselves as functionally disabled by COPD (usually Medical Research Council [MRC] grade 3 and above)
Bronchodilator therapy
· a short-acting beta2-agonist (SABA) or short-acting muscarinic antagonist (SAMA) is first-line treatment
· for patients who remain breathless or have exacerbations despite using short-acting bronchodilators the next step is determined by whether the patient has 'asthmatic features/features suggesting steroid responsiveness'
There are a number of criteria NICE suggest to determine whether a patient has asthmatic/steroid responsive features:
· any previous, secure diagnosis of asthma or of atopy
· a higher blood eosinophil count - note that NICE recommend a full blood count for all patients as part of the work-up
· substantial variation in FEV1 over time (at least 400 ml)
· substantial diurnal variation in peak expiratory flow (at least 20%)
Interestingly NICE do not recommend formal reversibility testing as one of the criteria. In the guidelines they state that 'routine spirometric reversibility testing is not necessary as part of the diagnostic process or to plan initial therapy with bronchodilators or corticosteroids. It may be unhelpful or misleading...'. They then go on to discuss why they have reached this conclusion. Please see the guidelines for more details.
No asthmatic features/features suggesting steroid responsiveness
· add a long-acting beta2-agonist (LABA) + long-acting muscarinic antagonist (LAMA)
o if already taking a SAMA, discontinue and switch to a SABA
Asthmatic features/features suggesting steroid responsiveness
· LABA + inhaled corticosteroid (ICS)
· if patients remain breathless or have exacerbations offer triple therapy i.e. LAMA + LABA + ICS
o if already taking a SAMA, discontinue and switch to a SABA
· NICE recommend the use of combined inhalers where possible
Oral theophylline
· NICE only recommends theophylline after trials of short and long-acting bronchodilators or to people who cannot used inhaled therapy
· the dose should be reduced if macrolide or fluoroquinolone antibiotics are co-prescribed
Oral prophylactic antibiotic therapy
· azithromycin prophylaxis is recommended in select patients
· patients should not smoke, have optimised standard treatments and continue to have exacerbations
· other prerequisites include a CT thorax (to exclude bronchiectasis) and sputum culture (to exclude atypical infections and tuberculosis)
· LFTs and an ECG to exclude QT prolongation should also be done as azithromycin can prolong the QT interval
Mucolytics
· should be 'considered' in patients with a chronic productive cough and continued if symptoms improve
Cor pulmonale
· features include peripheral oedema, raised jugular venous pressure, systolic parasternal heave, loud P2
· use a loop diuretic for oedema, consider long-term oxygen therapy
· ACE-inhibitors, calcium channel blockers and alpha blockers are not recommended by NICE
Factors which may improve survival in patients with stable COPD
· smoking cessation - the single most important intervention in patients who are still smoking
· long term oxygen therapy in patients who fit criteria
· lung volume reduction surgery in selected patients
From <https://www.passmedicine.com/review/textbook.php?s=#>
21 December 2020
21:53
Non-invasive ventilation
The British Thoracic Society (BTS) published guidelines in 2002 on the use of non-invasive ventilation in acute respiratory failure. Following these the Royal College of Physicians published guidelines in 2008.
Non-invasive ventilation - key indications
· COPD with respiratory acidosis pH 7.25-7.35*
· type II respiratory failure secondary to chest wall deformity, neuromuscular disease or obstructive sleep apnoea
· cardiogenic pulmonary oedema unresponsive to CPAP
· weaning from tracheal intubation
Recommended initial settings for bi-level pressure support in COPD
· Expiratory Positive Airway Pressure (EPAP): 4-5 cm H2O
· Inspiratory Positive Airway Pressure (IPAP): RCP advocate 10 cm H20 whilst BTS suggest 12-15 cm H2O
· back up rate: 15 breaths/min
· back up inspiration:expiration ratio: 1:3
*the BTS guidelines state that NIV can be used in patients who are more acidotic (i.e. pH < 7.25) but that a greater degree of monitoring is required (e.g. HDU) and a lower threshold for intubation and ventilation should be used
From <https://www.passmedicine.com/review/textbook.php?s=#>
21 December 2020
21:53
Pneumothorax: management
The British Thoracic Society (BTS) published updated guidelines for the management of spontaneous pneumothorax in 2010. A pneumothorax is termed primary if there is no underlying lung disease and secondary if there is.
Primary pneumothorax
Recommendations include:
· if the rim of air is < 2cm and the patient is not short of breath then discharge should be considered
· otherwise, aspiration should be attempted
· if this fails (defined as > 2 cm or still short of breath) then a chest drain should be inserted
· patients should be advised to avoid smoking to reduce the risk of further episodes - the lifetime risk of developing a pneumothorax in healthy smoking men is around 10% compared with around 0.1% in non-smoking men
Secondary pneumothorax
Recommendations include:
· if the patient is > 50 years old and the rim of air is > 2cm and/or the patient is short of breath then a chest drain should be inserted.
· otherwise aspiration should be attempted if the rim of air is between 1-2cm. If aspiration fails (i.e. pneumothorax is still greater then 1cm) a chest drain should be inserted. All patients should be admitted for at least 24 hours
· if the pneumothorax is less the 1cm then the BTS guidelines suggest giving oxygen and admitting for 24 hours
· regarding scuba diving, the BTS guidelines state: 'Diving should be permanently avoided unless the patient has undergone bilateral surgical pleurectomy and has normal lung function and chest CT scan postoperatively.'
Iatrogenic pneumothorax
Recommendations include:
· less likelihood of recurrence than spontaneous pneumothorax
· majority will resolve with observation, if treatment is required then aspiration should be used
· ventilated patients need chest drains, as may some patients with COPD
From <https://www.passmedicine.com/review/textbook.php?s=#>
21 December 2020
21:53
Respiratory tract infections: NICE guidelines
NICE issued guidance in 2008 on the management of respiratory tract infection, focusing on the prescribing of antibiotics for self-limiting respiratory tract infections in adults and children in primary care
A no antibiotic prescribing or delayed antibiotic prescribing approach is generally recommended for patients with acute otitis media, acute sore throat/acute pharyngitis/acute tonsillitis, common cold, acute rhinosinusitis or acute cough/acute bronchitis.
However, an immediate antibiotic prescribing approach may be considered for:
· children younger than 2 years with bilateral acute otitis media
· children with otorrhoea who have acute otitis media
· patients with acute sore throat/acute pharyngitis/acute tonsillitis when 3 or more Centor criteria are present
The Centor criteria* are as follows:
· presence of tonsillar exudate
· tender anterior cervical lymphadenopathy or lymphadenitis
· history of fever
· absence of cough
If the patient is deemed at risk of developing complications, an immediate antibiotic prescribing policy is recommended
· are systemically very unwell
· have symptoms and signs suggestive of serious illness and/or complications (particularly pneumonia, mastoiditis, peritonsillar abscess, peritonsillar cellulitis, intraorbital or intracranial complications)
· are at high risk of serious complications because of pre-existing comorbidity. This includes patients with significant heart, lung, renal, liver or neuromuscular disease, immunosuppression, cystic fibrosis, and young children who were born prematurely
· are older than 65 years with acute cough and two or more of the following, or older than 80 years with acute cough and one or more of the following:
· - hospitalisation in previous year
· - type 1 or type 2 diabetes
· - history of congestive heart failure
· - current use of oral glucocorticoids
The guidelines also suggest that patients should be advised how long respiratory tract infections may last:
· acute otitis media: 4 days
· acute sore throat/acute pharyngitis/acute tonsillitis: 1 week
· common cold: 1 1/2 weeks
· acute rhinosinusitis: 2 1/2 weeks
· acute cough/acute bronchitis: 3 weeks
*if 3 or more of the criteria are present there is a 40-60% chance the sore throat is caused by Group A beta-haemolytic Streptococcus
From <https://www.passmedicine.com/review/textbook.php?s=#>
21 December 2020
22:08
Pneumonia: assessment and management
Primary care setting
NICE recommends that patients should initially be assessed in primary care using the CRB65 criteria:
| Criterion | Marker |
| C | Confusion (abbreviated mental test score <= 8/10) |
| R | Respiration rate >= 30/min |
| B | Blood pressure: systolic <= 90 mmHg and/or diastolic <= 60 mmHg |
| 65 | Aged >= 65 years |
Patients are stratified for risk of death as follows:
· 0: low risk (less than 1% mortality risk)
· 1 or 2: intermediate risk (1-10% mortality risk)
· 3 or 4: high risk (more than 10% mortality risk).
NICE recommend, in conjunction with clinical judgement:
· home-based care for patients with a CRB65 score of 0
· hospital assessment for all other patients, particularly those with a CRB65 score of 2 or more.
NICE also mention point-of-care CRP test. This is currently not widely available but they make the following recommendation with reference to the use of antibiotic therapy:
· CRP < 20 mg/L - do not routinely offer antibiotic therapy
· CRP 20 - 100 mg/L - consider a delayed antibiotic prescription
· CRP > 100 mg/L - offer antibiotic therapy
Secondary care setting
Note that in hospital, once blood tests are available the CURB65, rather than the CRB65, can be used. This adds an extra criterion of urea > 7 mmol/L:
| Criterion | Marker |
| C | Confusion (abbreviated mental test score <= 8/10) |
| U | urea > 7 mmol/L |
| R | Respiration rate >= 30/min |
| B | Blood pressure: systolic <= 90 mmHg and/or diastolic <= 60 mmHg |
| 65 | Aged >= 65 years |
NICE recommend, in conjunction with clinical judgement:
· consider home-based care for patients with a CURB65 score of 0 or 1 - low risk (less than 3% mortality risk)
· consider hospital-based care for patients with a CURB65 score of 2 or more - intermediate risk (3-15% mortality risk)
· consider intensive care assessment for patients with a CURB65 score of 3 or more - high risk (more than 15% mortality risk)
Investigations
· chest x-ray
· in intermediate or high-risk patients NICE recommend blood and sputum cultures, pneumococcal and legionella urinary antigen tests
· CRP monitoring is recommend for admitted patients to help determine response to treatment
Management of low-severity community acquired pneumonia
· amoxicillin is first-line
· if penicillin allergic then use a macrolide or tetracycline
· NICE now recommend a 5 day course of antibiotics for patients with low severity community acquired pneumonia
Management of moderate and high-severity community acquired pneumonia
· dual antibiotic therapy is recommended with amoxicillin and a macrolide
· a 7-10 day course is recommended
· NICE recommend considering a beta-lactamase stable penicillin such as co-amoxiclav, ceftriaxone or piperacillin with tazobactam and a macrolide in high-severity community acquired pneumonia
Discharge criteria and advice post-discharge
NICE recommend that patients are not routinely discharged if in the past 24 hours they have had 2 or more of the following findings:
· temperature higher than 37.5°C
· respiratory rate 24 breaths per minute or more
· heart rate over 100 beats per minute
· systolic blood pressure 90 mmHg or less
· oxygen saturation under 90% on room air
· abnormal mental status
· inability to eat without assistance.
They also recommend delaying discharge if the temperature is higher than 37.5°C.
NICE recommend that the following information is given to patients with pneumonia in terms of how quickly their symptoms should symptoms should resolve:
| Time | Progress |
| 1 week | Fever should have resolved |
| 4 weeks | Chest pain and sputum production should have substantially reduced |
| 6 weeks | Cough and breathlessness should have substantially reduced |
| 3 months | Most symptoms should have resolved but fatigue may still be present |
| 6 months | Most people will feel back to normal. |
From <https://www.passmedicine.com/question/questions.php?q=0>
21 December 2020
22:14
Sarcoidosis: investigation
There is no one diagnostic test for sarcoidosis and hence diagnosis is still largely clinical. ACE levels have a sensitivity of 60% and specificity of 70% and are therefore not reliable in the diagnosis of sarcoidosis although they may have a role in monitoring disease activity. Routine bloods may show hypercalcaemia (seen in 10% if patients) and a raised ESR
A chest x-ray may show the following changes:
· stage 0 = normal
· stage 1 = bilateral hilar lymphadenopathy (BHL)
· stage 2 = BHL + interstitial infiltrates
· stage 3 = diffuse interstitial infiltrates only
· stage 4 = diffuse fibrosis
Other investigations*
· spirometry: may show a restrictive defect
· tissue biopsy: non-caseating granulomas
· gallium-67 scan - not used routinely
| | |
| © Image used on license from Radiopaedia | |
Chest x-ray and CT scan showing stage 2 sarcoidosis with both bilateral hilar lymphadenopathy + interstitial infiltrates. The reticulonodular opacities are particularly noted in the upper zones. Remember that pulmonary fibrosis (which this case has not yet progressed to) may be divided into conditions which predominately affect the upper zones and those which predominately affect the lower zones - sarcoidosis is one of the former. The CT of the chest demonstrates diffuse areas of nodularity predominantly in a peribronchial distribution with patchy areas of consolidation particularly in the upper lobes. There is some surrounding ground glass opacities. No gross reticular changes to suggest fibrosis.
*the Kveim test (where part of the spleen from a patient with known sarcoidosis is injected under the skin) is no longer performed due to concerns about cross-infection
From <https://www.passmedicine.com/question/questions.php?q=0>
21 December 2020
22:23
Chest drain
A chest drain is a tube inserted into the pleural cavity which creates a one-way valve, allowing movement of air or liquid out of the cavity.
Chest drain insertion is indicated in cases of:
· Pleural effusion
· Pneumothorax not suitable for conservative management or aspiration
· Empyema
· Haemothorax
· Haemopneumothorax
· Chylothorax
· In some cases of penetrating chest wall injury in ventilated patients
Insertion of a chest drain is relatively contraindicated in patients with any of the following:
· INR > 1.3
· Platelet count < 75
· Pulmonary bullae
· Pleural adhesions
Please note, all of the above represent only relative contraindications, addressing respiratory compromise in an emergency situation should always be on an individual case basis.
Once patient consent has been obtained and patient imaging assessed, the patient should be positioned in a supine position or at a 45º angle. The patient's forearm may be positioned behind the patient's head to allow easy access to the axilla. Identify the 5th intercostal space in the midaxillary line. Alternatively, positioning may be determined by ultrasound guidance, British Thoracic Society Guidance 'strongly recommend' use of ultrasound guidance in all cases of fluid within the pleura. The area should be anaesthetised using local anaesthetic injection (lidocaine, up to 3mg/kg). The drainage tube should then be inserted using a Seldinger technique. The drain tubing should then be secured using either a straight stitch or with an adhesive dressing.
Positioning can be confirmed by aspiration of fluid from the drainage tubing, by 'swinging' of the fluid within the drain tubing when the patient inspires and on chest x-ray.
Complications that may occur and which the patient should be advised of in the process of obtaining consent:
· Failure of insertion - the drain may be abutting the apical pleura, in which case it should be pulled back, or may be subcutaneous or in rare cases could enter the abdominal cavity. In both latter cases, the drain should be removed and re-sited.
· Bleeding - around the site of the drain or into the pleural space
· Infection
· Penetration of the lung
· Re-expansion pulmonary oedema
Re-expansion pulmonary oedema may be preceded by the onset of a cough and/or shortness of breath. In the event of concerns regarding re-expansion pulmonary oedema, the chest drain should be clamped and an urgent chest x-ray should be obtained. To avoid re-expansion pulmonary oedema, it is recommended that the drain tubing should be clamped regularly in the event of rapid fluid output i.e. drain output should not exceed 1L of fluid over a short period of time (less than 6 hours).
Removal of the chest drain is dependent upon the indication for insertion:
· In cases of fluid drainage from the pleural cavity, the drain should be removed when there has been no output for > 24 hours and imaging shows resolution of the fluid collection.
· In cases of pneumothorax, the drain should be removed when it is no longer bubbling spontaneously or when the patient coughs and ideally when imaging shows resolution of the pneumothorax.
· Drains inserted in cases of penetrating chest injury should be reviewed by the specialist to confirm an appropriate time for removal.
From <https://www.passmedicine.com/question/questions.php?q=0>
21 December 2020
22:53
Asbestos and the lung
Asbestos can cause a variety of lung disease from benign pleural plaques to mesothelioma.
Pleural plaques
Pleural plaques are benign and do not undergo malignant change. They are the most common form of asbestos related lung disease and generally occur after a latent period of 20-40 years.
Pleural thickening
Asbestos exposure may cause diffuse pleural thickening in a similar pattern to that seen following an empyema or haemothorax. The underlying pathophysiology is not fully understood.
Asbestosis
The severity of asbestosis is related to the length of exposure. This is in contrast to mesothelioma where even very limited exposure can cause disease. The latent period is typically 15-30 years. Asbestosis typically causes lower lobe fibrosis. As with other forms of lung fibrosis the most common symptoms are shortness-of-breath and reduced exercise tolerance.
Mesothelioma
Mesothelioma is a malignant disease of the pleura. Crocidolite (blue) asbestos is the most dangerous form.
Possible features
· progressive shortness-of-breath
· chest pain
· pleural effusion
Patients are usually offered palliative chemotherapy and there is also a limited role for surgery and radiotherapy. Unfortunately the prognosis is very poor, with a median survival from diagnosis of 8-14 months.
Lung cancer
Asbestos exposure is a risk factor for lung cancer and also has a synergistic effect with cigarette smoke.
From <https://www.passmedicine.com/question/questions.php?q=0>
21 December 2020
23:05
Acute asthma: management
The British Thoracic Society (BTS) classify patients with acute asthma into moderate, severe or life-threatening categories.
| Moderate | Severe | Life-threatening |
| PEFR 50-75% best or predicted Speech normal RR < 25 / min Pulse < 110 bpm | PEFR 33 - 50% best or predicted Can't complete sentences RR > 25/min Pulse > 110 bpm | PEFR < 33% best or predicted Oxygen sats < 92% 'Normal' pC02 (4.6-6.0 kPa) Silent chest, cyanosis or feeble respiratory effort Bradycardia, dysrhythmia or hypotension Exhaustion, confusion or coma |
Note that a patient having any one of the life-threatening features should be treated as having a life-threatening attack.
A fourth category, 'Near-fatal asthma', is also recognised characterised by a raised pC02 and/or requiring mechanical ventilation with raised inflation pressures.
Further assessment
· the BTS guidelines recommend arterial blood gases for patients with oxygen sats < 92%
· a chest x-ray is not routinely recommended, unless:
o life-threatening asthma
o suspected pneumothorax
o failure to respond to treatment
Management
· admission
o all patients with life-threatening should be admitted in hospital
o patients with features of severe acute asthma should also be admitted if they fail to respond to initial treatment.
o other admission criteria include a previous near-fatal asthma attack, pregnancy, an attack occurring despite already using oral corticosteroid and presentation at night
· oxygen
o if patients are hypoxaemic, it is important to start them on supplemental oxygen therapy
o if patients are acutely unwell they should be started on 15L of supplemental via a non-rebreathe mask, which can then be titrated down to a flow rate where they are able to maintain a SpO₂ 94-98%.
· bronchodilation with short-acting beta₂-agonists (SABA)
o high-dose inhaled SABA e.g. salbutamol, terbutaline
o in patients without features of life-threatening or near-fatal asthma, this can be given by a standard pressurised metered-dose inhaler (pMDI) or by an oxygen-driven nebulizer
o in patients with features of a life-threatening exacerbation of asthma, nebulised SABA is recommended
· corticosteroid
o all patients should be given 40-50mg of prednisolone orally (PO) daily, which should be continued for at least five days or until the patient recovers from the attack
o during this time, patients should continue their normal medication routine including inhaled corticosteroids.
· ipratropium bromide: in patients with severe or life-threatening asthma, or in patients who have not responded to beta₂-agonist and corticosteroid treatment, nebulised ipratropium bromide, a short-acting muscarinic antagonist
· IV magnesium sulphate
o the BTS notes that the evidence base is mixed for this treatment that is now commonly given for severe/life-threatening asthma
· IV aminophylline may be considered following consultation with senior medical staff
· patients who fail to respond require senior critical care support and should be treated in an appropriate ITU/HDU setting. Treatment options include:
o intubation and ventilation
o extracorporeal membrane oxygenation (ECMO)
Criteria for discharge
· been stable on their discharge medication (i.e. no nebulisers or oxygen) for 12–24 hours
· inhaler technique checked and recorded
· PEF >75% of best or predicted
From <https://www.passmedicine.com/question/questions.php?q=0>
22 December 2020
16:09
Arterial blood gas interpretation
The Resuscitation Council (UK) advocate a 5 step approach to arterial blood gas interpretation.
1. How is the patient?
2. Is the patient hypoxaemic?
· the Pa02 on air should be >10 kPa
3. Is the patient acidaemic (pH <7.35) or alkalaemic (pH >7.45)
4. Respiratory component: What has happened to the PaCO2?
· PaCO2 > 6.0 kPa suggests a respiratory acidosis (or respiratory compensation for a metabolic alkalosis)
· PaCO2 < 4.7 kPa suggests a respiratory alkalosis (or respiratory compensation for a metabolic acidosis)
5. Metabolic component: What is the bicarbonate level/base excess?
· bicarbonate < 22 mmol/l (or a base excess < - 2mmol/l) suggests a metabolic acidosis (or renal compensation for a respiratory alkalosis)
· bicarbonate > 26 mmol/l (or a base excess > + 2mmol/l) suggests a metabolic alkalosis (or renal compensation for a respiratory acidosis)
ROME
Respiratory = Opposite
· low pH + high PaCO2 i.e. acidosis, or
· high pH + low PaCO2 i.e. alkalosis
Metabolic = Equal
· low pH + low bicarbonate i.e. acidosis, or
· high pH + high bicarbonate i.e. akalosis
From <https://www.passmedicine.com/question/questions.php?q=0>
22 December 2020
16:14
Sarcoidosis
Sarcoidosis is a multisystem disorder of unknown aetiology characterised by non-caseating granulomas. It is more common in young adults and in people of African descent
Features
· acute: erythema nodosum, bilateral hilar lymphadenopathy, swinging fever, polyarthralgia
· insidious: dyspnoea, non-productive cough, malaise, weight loss
· skin: lupus pernio
· hypercalcaemia: macrophages inside the granulomas cause an increased conversion of vitamin D to its active form (1,25-dihydroxycholecalciferol)
Syndromes associated with sarcoidosis
Lofgren's syndrome is an acute form of the disease characterised by bilateral hilar lymphadenopathy (BHL), erythema nodosum, fever and polyarthralgia. It usually carries an excellent prognosis
In Mikulicz syndrome* there is enlargement of the parotid and lacrimal glands due to sarcoidosis, tuberculosis or lymphoma
Heerfordt's syndrome (uveoparotid fever) there is parotid enlargement, fever and uveitis secondary to sarcoidosis
*this term is now considered outdated and unhelpful by many as there is a confusing overlap with Sjogren's syndrome
From <https://www.passmedicine.com/question/questions.php?q=0>
About 5 % of patients with sarcoidosis have myocardial involvement, of which 30% develop complete heart block.
From <https://mle.ncl.ac.uk/cases/page/18128/>
In addition to CXR, further radiological investigations of sarcoid include
· CT
· High Resolution CT
· PET-CT
It is possible to biopsy some lesions. Characteristic histology shows:
· non-caseating granulomas
· Schaumann bodies
· Asteroid bodies
Biochemistry:
· ACE (angiotensin-converting enzyme) is elevated in Sarcoid
· Bone Profile - serum calcium is also elevated
From <https://mle.ncl.ac.uk/cases/page/17853/>
There are a number of differential diagnoses relevant to each of Scadding's Stages
Stage 1
Mediastinal node enlargement - Primary lung cancer, metastasis from other malignancy, Lymphoma, Kaposi Sarcoma, Pulmonary TB, Silicosis
Stage 3
chronic air space opacity is also seen in Hypersensitivity Pneumonitis and Cryptogenic Organizing Pneumonia
Stage 4
Idiopathic Pulmonary Fibrosis
Löfgren syndrome
An acute presentation of systemic Sarcoid. Typically occurs in women, aged 20-40 years.
Features:
· Fever
· Lymphadenopathy
· Erythema Nodosum
· Polyarticular Arthritis
Heerfordt's syndrome
An acute presentation of sarcoid affecting a similar demographic as in Löfgren syndrome, however it is relatively rare.
Features:
· Fever
· Uveitis
· Parotitis
Most patient's with Sarcoid do not require treatment.
Indications for treatment with steroids:
· Progressive or clearly symptomatic lung disease
· Cardiac sarcoid
· Neuro sarcoid
· Uveitis
· Hypercalcaemia
The aim of steroid therapy is to reduce inflammation and prevent further damage and fibrosis to tissues. Long term steroid use has multiple complications which should be balanced with therapeutic effects.
In patients who cannot tolerate steroids alternatives include methotrexate and Infliximab.
From <https://mle.ncl.ac.uk/cases/page/17856/>
H
22 December 2020
17:16
Allergic bronchopulmonary aspergillosis
Allergic bronchopulmonary aspergillosis results from an allergy to Aspergillus spores. In the exam questions often give a history of bronchiectasis and eosinophilia.
Features
· bronchoconstriction: wheeze, cough, dyspnoea. Patients may have a previous label of asthma
· bronchiectasis (proximal)
Investigations
· eosinophilia
· flitting CXR changes
· positive radioallergosorbent (RAST) test to Aspergillus
· positive IgG precipitins (not as positive as in aspergilloma)
· raised IgE
Management
· oral glucocorticoids
· itraconazole is sometimes introduced as a second-line agent
| | |
| © Image used on license from Radiopaedia | |
Chest x-ray of a 40-year-old woman with ABPA demonstrating a mass overlying the left hilum. In the right upper parahilar region a few ring shadow / tram track opacities are also noted, suggestive of bronchiectasis
| | |
| © Image used on license from Radiopaedia | |
CT scan from the same patient. CT reveals a branching lesion in the superior segment of the left lower lobe with classic finger in glove appearance which represents of mucous filling dilated bronchi (i.e. bronchocoeles). Bronchocoeles are a common feature of allergic bronchopulmonary aspergillosis (ABPA)
From <https://www.passmedicine.com/question/questions.php?q=0>
22 December 2020
17:59
Respiratory alkalosis
Common causes
· anxiety leading to hyperventilation
· pulmonary embolism
· salicylate poisoning*
· CNS disorders: stroke, subarachnoid haemorrhage, encephalitis
· altitude
· pregnancy
*salicylate overdose leads to a mixed respiratory alkalosis and metabolic acidosis. Early stimulation of the respiratory centre leads to a respiratory alkalosis whilst later the direct acid effects of salicylates (combined with acute renal failure) may lead to an acidosis
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From <https://www.passmedicine.com/question/questions.php?q=0>
22 December 2020
18:04
COPD: investigation and diagnosis
NICE recommend considering a diagnosis of COPD in patients over 35 years of age who are smokers or ex-smokers and have symptoms such as exertional breathlessness, chronic cough or regular sputum production.
The following investigations are recommended in patients with suspected COPD:
· post-bronchodilator spirometry to demonstrate airflow obstruction: FEV1/FVC ratio less than 70%
· chest x-ray: hyperinflation, bullae, flat hemidiaphragm. Also important to exclude lung cancer
· full blood count: exclude secondary polycythaemia
· body mass index (BMI) calculation
The severity of COPD is categorised using the FEV1*:
| Post-bronchodilator FEV1/FVC | FEV1 (of predicted) | Severity |
| < 0.7 | > 80% | Stage 1 - Mild - symptoms should be present to diagnose COPD in these patients |
| < 0.7 | 50-79% | Stage 2 - Moderate |
| < 0.7 | 30-49% | Stage 3 - Severe |
| < 0.7 | < 30% | Stage 4 - Very severe |
Measuring peak expiratory flow is of limited value in COPD, as it may underestimate the degree of airflow obstruction.
*note that the grading system has changed following the 2010 NICE guidelines. If the FEV1 is greater than 80% predicted but the post-bronchodilator FEV1/FVC is < 0.7 then this is classified as Stage 1 - mild
From <https://www.passmedicine.com/question/questions.php?q=0>
28 December 2020
22:13
allergic bronchopulmonary aspergillosis.
Major criteria
· Clinical asthma
· Proximal bronchiectasis
· Eosinophilia
· Immediate skin reactivity to Aspergillus antigen
· Increased serum IgE
Minor criteria
· Sputum with fungal elements
· Brown sputum flecks
· Delayed skin reactivity to fungal antigens
Loeffler syndrome
· Associated wth tropical infections
Asthma
· Bronchiectasis is not associated with true asthma
Churg Strauss
· P-ANCA positive
DRESS syndrome
· Rash with systemic fever an eosinophilia
From <https://mle.ncl.ac.uk/cases/page/18128/>
silicosis
28 December 2020
22:46
CXR in silicosis
· Multiple and small well-rounded nodules, particularly in the upper zone.
· Apical hilar retraction
· Secondary TB infection in apical cavities
· Hilar egg-shell calcification
Berylliosis
· Exposure to beryllium in aeronautics and electronics industries
Histoplasmosis
· Asymptomatic mycosis with mediastinal involvement
Tuberculosis
· Tend not to cause eggshell calcification
Sarcoidosis
· Causes hypercalcaemia with sarcoid nodules in the skin, lungs and other organs
From <https://mle.ncl.ac.uk/cases/page/18128/>
farmer's lung
28 December 2020
23:00
Contaminated hay is the most common source of Saccharopolyspora rectivirgula which is responsible for farmer's lung, a form of hypersensitivity pneumonitis.
From <https://mle.ncl.ac.uk/cases/page/18128/>
Hypersentitivity Pneumonitis
05 January 2021
16:36
AKA Extrinsic Allergic Alveolitis, is characterised by diffuse granulomatous inflammation of the lung parenchyma and airways in patients who have been sensitized by repeated inhalation of organic antigens
Acute form - 4-6 hours after exposure - SOB, dry cough, fever, rigors and crackles
Sub-acute - similar symptoms to acute but less severe and ongoing for weeks to months
Chronic - increasing SOB, malaise, weight loss, type 1 respiratory failure, cor pulmonale
There a multiple varieties including:
· Bird Fancier/Pigeon Fancier's Lung - proteins in bird droppings
· Farmer's lung/mushroom workers lung - fungal spores
· Malt Worker's Lung
· Cheese washer's lung
· Saw Mill worker's lung
· Suberosis
The history is the most important thing in hypersensitivity pneumonitis - always ask about potential exposures. Examine the whole patient and look for clues about their occupation or hobbies.
Blood tests
· FBC - elevated neutrophils in acute stage
· ESR - Elevated
· Positive serum precipitins in the chronic stage
Imaging
· CXR - early stages may seen ground-glass opacities. Then volume loss, reticular pattern and honey combing in severe disease. Upper zone of the lungs often more involved than lower zones
· CT - will often see ground glass appearance and nodule formation
Multiple centrilobular ground glass nodules and anterior subpleural reticulation. (Case courtesy of Dr Mark Holland, Radiopaedia.org, rID: 19551)
Special Tests
· Lung function tests - restrictive pattern
· Bronchial lavage - elevated mast cells and lymphocytes
Management
The first important step in management is removal and avoidance of the allergen.
A course of systemic corticosteroids can also be used - typically this will start with a high dose and then taper down