skip to main content

irAEs/Perforation — SCE Medical Oncology MCQ

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

HardOncological EmergenciesirAEs/PerforationSCE Medical Oncology

A 55-year-old on nivolumab-ipilimumab has six days of bloody diarrhoea and CT-proven pancolitis. Before immunosuppression is started he develops abrupt generalised peritonism; repeat CT shows free gas adjacent to the inflamed transverse colon. What complication has occurred?

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

Reveal the answer and explanation

Correct answer: A — Immune colitis with full-thickness colonic perforation in this patient

Abrupt peritonism with free gas adjacent to checkpoint-inflamed colon identifies full-thickness colonic perforation. Immune-mediated colitis complicated by toxic megacolon in this patient: toxic megacolon causes marked dilatation and systemic toxicity rather than focal free gas. Immune-mediated colitis complicated by transmural ischaemia in this patient: ischaemia is possible but the decisive imaging finding establishes perforation. Immune-mediated colitis complicated by intra-abdominal abscess in this patient: an abscess is a contained collection rather than free intraperitoneal gas with peritonism. Immune-mediated colitis complicated by fulminant ileus in this patient: ileus does not itself explain free gas adjacent to inflamed colon.

Reference: West of Scotland Cancer Network immune-related adverse-events guideline (Version 4.0, March 2024; review due March 2027): https://rightdecisions.scot.nhs.uk/media/b11eeh40/woscan-immunotherapy-iraes-guideline-v40.pdf; OPDIVO 10 mg/mL UK summary of product characteristics (Current UK SmPC, updated July 2026): https://www.medicines.org.uk/emc/product/6888/smpc