skip to main content

ANCA Vasculitis — SCE Rheumatology MCQ

Instant feedback + full explanation. One question, done properly.

HardRheumatology EmergenciesANCA VasculitisSCE Rheumatology

A 50-year-old man with granulomatosis with polyangiitis develops haemoptysis and rapidly progressive renal impairment, with serum creatinine rising from 120 to 680 micromol/L over 5 days. His haemoglobin has fallen from 128 to 87 g/L and CT shows new bilateral diffuse ground-glass opacification. His respiratory rate is 36 breaths/min, oxygen saturation is 82% despite 15 L/min oxygen, and arterial PaO2 is 6.8 kPa. Serum potassium is 4.8 mmol/L, bicarbonate is 22 mmol/L and arterial pH is 7.37; there is no clinical pulmonary oedema or pericarditis. Which current manifestation represents the most immediate threat to life and should determine the first escalation to critical care?

Educational content. Not a substitute for clinical judgement or local policy.

Reveal the answer and explanation

Correct answer: E — Diffuse alveolar haemorrhage causing acute hypoxaemic respiratory failure

The immediate threat is diffuse alveolar haemorrhage causing severe acute hypoxaemic respiratory failure. The haemoptysis, falling haemoglobin, bilateral infiltrates and profound hypoxaemia establish pulmonary capillaritis with life-threatening alveolar bleeding, requiring immediate critical-care respiratory support and urgent AAV remission induction. The rapidly progressive glomerulonephritis is also organ-threatening, but creatinine alone is not an indication for emergency renal replacement therapy; potassium, pH and bicarbonate are acceptable, with no refractory pulmonary oedema or uraemic pericarditis. Subglottic stenosis and orbital inflammation can become emergencies, but neither is present here. Saddle-nose deformity reflects accumulated structural damage rather than acute disease. Current UK guidance supports high-dose glucocorticoids with rituximab or cyclophosphamide; combined rituximab and cyclophosphamide may be considered in selected life-threatening disease but is not universally required.

Reference: Fussner LA et al. Alveolar Hemorrhage in Antineutrophil Cytoplasmic Antibody-Associated Vasculitis: Results of an International Randomized Controlled Trial (PEXIVAS). American Journal of Respiratory and Critical Care Medicine. 2024;209:1141-1151. https://pubmed.ncbi.nlm.nih.gov/38346237/