OSCE — Acute & Chronic Diarrhoea · MBBS OSCE

Brief (to candidate)

You will assess a patient with a presentation consistent with Acute & Chronic Diarrhoea.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.

Clinical context

Diarrhoea is three or more loose or watery stools in 24 hours (or more frequent than is normal for the individual). Acute diarrhoea (under 14 days) is usually infective and self-limiting — viral (norovirus, rotavirus), bacterial (enterotoxigenic E. coli, Campylobacter, Salmonella, Shigella), Clostridioides difficile (after antibiotics) or parasitic (Giardia, Cryptosporidium, Entamoeba) — and the central clinical task is to separate the self-limiting viral illness (reassure, rehydrate) from disease that needs testing or specific treatment: invasive bacterial infection, C. difficile, or an underlying chronic cause. Chronic diarrhoea (over 4 weeks) has a wide differential including irritable bo

Candidate tasks

Clarify onset, severity, associated features, and red-flag symptoms.
State focused examination priorities.
List first-line investigations and any named score/criteria.
Give immediate resuscitation steps.
Outline definitive management with doses/routes where standard.
Name complications and disposition (ward / HDU / theatre / discharge safety-net).
Mention one special-population modifier (pregnancy, child, elderly, CKD).

Examiner checklist

Domain	Pass behaviours
Definition	Correct working diagnosis language
Assessment	Focused, prioritised, red flags sought
Investigations	Appropriate first-line + interpretation
Emergency care	ABC / time-critical actions first
Definitive care	Specific drugs/procedures, not generic phrases
Safety	Bloody or mucoid diarrhoea with fever — invasive bacterial infection (Shigella,
Safety	Diarrhoea during or after antibiotics or healthcare exposure — Clostridioides di
Safety	Bloody diarrhoea after undercooked beef with falling platelets and AKI — Shiga-t
Communication	Clear plan and safety-netting

Model outline

Lead with the working diagnosis and life threats. Resuscitate before definitive tests when unstable. Use guideline-standard therapy with named agents and doses. Document escalation criteria and follow-up. A safe candidate is specific, structured, and never delays critical care for non-urgent imaging.