Asthma & ABPA flashcards
25 high-yield MRCP Part 1 cards from the Intellect Medicos Respiratory Medicine course. Try to answer each question before you open it — then study them properly with spaced repetition, which brings each card back just before you would forget it.
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Under NICE/BTS/SIGN 2024 (NG245), what are the first-line objective tests for diagnosing asthma in adults?
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A blood eosinophil count or a FeNO (fractional exhaled nitric oxide) test.
Why? Either can rule asthma in: eosinophils above the lab reference range, or FeNO of 50 ppb or more.
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What change in FEV1 after a bronchodilator counts as positive reversibility for diagnosing asthma in adults (NG245)?
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An FEV1 rise of at least 12% AND at least 200 mL (or a rise of at least 10% of predicted FEV1).
Why? Significant reversibility shows variable airflow obstruction, the hallmark of asthma.
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If spirometry is unavailable, how should peak flow be used to diagnose asthma (NG245)?
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Twice-daily PEF for 2 weeks; variability of 20% or more supports asthma.
Why? Asthma causes variable airflow obstruction, so peak flow swings between morning and evening readings.
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What is the first-line treatment for newly diagnosed asthma in a person aged 12 or over (NG245)?
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As-needed low-dose ICS/formoterol combination inhaler (anti-inflammatory reliever, "AIR" therapy).
Why? Every reliever dose also delivers steroid, which treats airway inflammation and lowers exacerbation risk.
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An adult's asthma is uncontrolled on as-needed ICS/formoterol (AIR). What is the next step (NG245)?
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Low-dose MART (maintenance and reliever therapy with ICS/formoterol).
Why? MART uses the same ICS/formoterol inhaler for regular maintenance and for relief. If still uncontrolled, step up to moderate-dose MART.
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A 34-year-old woman with asthma remains uncontrolled on moderate-dose MART despite good adherence and inhaler technique. Her FeNO and blood eosinophil count are both normal. What is the next step (NG245)?
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Add a trial of a leukotriene receptor antagonist (LTRA) or a LAMA for 8–12 weeks.
Why? If neither marker is raised, add LTRA or LAMA. If either marker is raised, refer to a specialist asthma service instead.
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Why is formoterol, rather than salmeterol, the LABA used in MART and AIR regimens?
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Formoterol has a fast onset of action, so it works as a reliever as well as a long-acting bronchodilator.
Why? Salmeterol has a slow onset, so it cannot be used for symptom relief.
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What is the mechanism of action of omalizumab?
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Monoclonal antibody against IgE (anti-IgE).
Why? It binds free IgE and stops it attaching to mast cells, reducing allergic (type I) inflammation. Used in severe allergic asthma.
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What is the target of mepolizumab, used for severe eosinophilic asthma?
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Interleukin-5 (IL-5).
Why? IL-5 drives eosinophil production and survival, so blocking it lowers eosinophils and exacerbations. Reslizumab also targets IL-5.
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What is the mechanism of action of montelukast?
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Cysteinyl leukotriene (CysLT1) receptor antagonist.
Why? Leukotrienes cause bronchoconstriction, mucus secretion and eosinophilic inflammation; blocking their receptor reduces these.
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What MHRA safety warning applies to montelukast?
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Neuropsychiatric reactions, e.g. sleep disturbance, nightmares, depression, agitation, hallucinations and suicidal thoughts.
Why? Stop montelukast if new or worsening neuropsychiatric symptoms appear, and tell patients and carers to seek advice promptly. A boxed warning was added to the product information in 2024.
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Name three features of LIFE-THREATENING acute asthma.
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Any three of: PEF < 33% best/predicted, SpO2 < 92%, silent chest, cyanosis, poor respiratory effort, arrhythmia, hypotension, exhaustion, confusion, normal PaCO2.
Why? These signal the patient is tiring and close to respiratory arrest, needing senior and ICU input.
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Acute SEVERE asthma: PEF ______ of best or predicted, respiratory rate ≥ 25/min, heart rate ≥ 110/min, or unable to complete sentences.
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33–50%
Why? Moderate asthma is PEF > 50–75%; life-threatening is PEF < 33%.
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A 22-year-old with acute asthma has been on back-to-back nebulisers for 1 hour. She looks tired. ABG: pH 7.38, PaCO2 5.3 kPa, PaO2 8.4 kPa. How should the PaCO2 be interpreted?
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A "normal" PaCO2 is a life-threatening sign: she is tiring and may be heading for respiratory failure.
Why? In acute asthma the patient should be hyperventilating with a low PaCO2. A normal or rising PaCO2 means exhaustion; a raised PaCO2 defines near-fatal asthma.
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What is the oral prednisolone dose for an adult with an acute asthma attack?
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40–50 mg once daily for at least 5 days (it can then be stopped without tapering).
Why? Early systemic steroids reduce airway inflammation and lower the risk of relapse and death.
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In acute asthma, when is IV magnesium sulfate given, and at what dose?
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A single dose of 1.2–2 g IV over 20 minutes for acute severe or life-threatening asthma not responding to initial bronchodilators.
Why? Magnesium relaxes bronchial smooth muscle (it reduces calcium influx).
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Which nebulised drug is added in acute asthma when the response to nebulised salbutamol is poor?
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Ipratropium bromide (a short-acting muscarinic antagonist).
Why? It adds anticholinergic bronchodilation to the beta-2 agonist in acute severe or life-threatening asthma.
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Which electrolyte disturbance is caused by high-dose nebulised salbutamol?
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Hypokalaemia.
Why? Beta-2 agonists drive potassium into cells via Na+/K+-ATPase. Other effects: tremor, tachycardia and lactic acidosis.
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What is the most common cause of occupational asthma?
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Isocyanates (e.g. spray paints, polyurethane foam).
Why? Other agents: flour (bakers), animal proteins (lab workers), epoxy resins, platinum/chromium salts, wood dust.
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What is the key investigation used to confirm occupational asthma?
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Serial peak flow monitoring, at least 4 times a day, both at work and away from work.
Why? It shows worsening on work days and improvement at weekends or on holiday. The notes advise at least 3 weeks at work and 2 weeks away.
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A pregnant woman with asthma asks to stop her inhaled steroid. What should she be advised?
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Continue her usual asthma treatment, including steroids; do not withhold them because of pregnancy.
Why? Poorly controlled asthma is a greater risk to mother and baby than the medicines.
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A 40-year-old with long-standing asthma has worsening wheeze and coughs up brown mucus plugs. Total IgE is over 1000 IU/mL, and HRCT shows central bronchiectasis with "finger-in-glove" opacities. What is the first-line treatment?
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Oral corticosteroids (with itraconazole as an adjunct).
Why? This is allergic bronchopulmonary aspergillosis (ABPA). Steroids control the hypersensitivity reaction; antifungals reduce the fungal load and steroid need.
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Which bronchiectasis distribution is characteristic of ABPA?
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Central (proximal) bronchiectasis.
Why? Mucus impaction and inflammation affect the large central airways; most other causes give peripheral/basal bronchiectasis.
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What is the classic chest X-ray sign of an aspergilloma?
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A rounded opacity within a cavity surrounded by a crescent of air (air crescent sign).
Why? An aspergilloma is a mobile fungal ball colonising a pre-existing cavity (e.g. old TB), without tissue invasion.
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How is severe haemoptysis from an aspergilloma managed?
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Bronchial artery embolisation (surgical resection is the definitive option).
Why? Haemoptysis is the main danger of an aspergilloma; long-term oral itraconazole is used if surgery is not possible.