Pulmonology
Pulmonology questions reward pattern recognition on spirometry, arterial blood gases, and imaging, plus the safety steps in acute respiratory presentations.
COPD
Diagnosis requires post-bronchodilator FEV1/FVC <0.70. Grade with mMRC/CAT and exacerbation history (ABE groups). In exacerbation: titrate oxygen to SpO2 88-92%, give short-acting bronchodilators, prednisolone 40 mg for 5 days, and antibiotics when sputum purulence increases or ventilatory support is needed. Non-invasive ventilation is indicated for pH 7.25-7.35 with hypercapnia.
Asthma
Variable airflow limitation: FEV1 reversibility >12% and >200 mL, or peak-flow variability. Acute severe attack: cannot complete sentences, respiratory rate >25, heart rate >110, PEF 33-50% of predicted. Treat with oxygen, repeated salbutamol plus ipratropium, systemic steroids, and IV magnesium for life-threatening features.
Pulmonary embolism
Estimate clinical probability first. PERC excludes PE in genuinely low-risk patients; Wells or Geneva determines whether to order D-dimer or go directly to CTPA. D-dimer is a rule-out test only and is uninterpretable in hospitalised or pregnant patients without age adjustment.
Worked example
A 34-year-old woman, 10 days after caesarean delivery, has sudden dyspnoea, heart rate 118, SpO2 91%. Surgery within 4 weeks makes PE likely, so order CTPA directly; a D-dimer would not change the next step and only delays imaging. Had she been low probability with a negative high-sensitivity D-dimer (<500), PE would be excluded without contrast.
Traps that cost marks
- Uncapped high-flow oxygen in a CO2 retainer.
- Treating wheeze as asthma in a smoker with fixed obstruction.
- Ordering CTPA in severe renal failure without considering V/Q scanning.