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ANCA/Anti-GBM Overlap — SCE Rheumatology MCQ

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HardVasculitisANCA/Anti-GBM OverlapSCE Rheumatology

A patient presents with pulmonary haemorrhage and rapidly progressive glomerulonephritis. Both PR3-ANCA and anti-GBM antibodies are strongly positive, and renal biopsy shows crescentic necrotising glomerulonephritis with linear IgG. Which long-term principle distinguishes this from isolated anti-GBM disease?

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Reveal the answer and explanation

Correct answer: D — Use plasma exchange and overlap induction, then AAV-style relapse-prevention maintenance

Explanation lettering: B = shown as A · A = shown as B · E = shown as D · D = shown as E

E is correct. Double-positive disease has the severe early phenotype of anti-GBM disease, so plasma exchange plus glucocorticoid and cyclophosphamide- or rituximab-based induction is required, but it also has the relapse propensity of ANCA-associated vasculitis. KDIGO therefore supports AAV-style maintenance after remission, unlike most isolated anti-GBM disease. A undertreats both pulmonary haemorrhage and cellular autoimmunity. B omits urgent pathogenic-antibody removal. C invents an infectious interpretation. D mistakes an induction procedure for a practical lifelong maintenance strategy. Antibody kinetics, renal recovery potential, pulmonary haemorrhage and infection risk determine details, but the early anti-GBM/late AAV distinction is the key principle.

Reference: KDIGO 2024 clinical practice guideline for ANCA-associated vasculitis: https://kdigo.org/wp-content/uploads/2024/04/KDIGO-2024-ANCA-Vasculitis-Guideline_Update.pdf