MBBS OSCE · General Medicine
OSCE — Intra-Abdominal Infection & Peritonitis
Eight-minute OSCE station on Intra-Abdominal Infection & Peritonitis: focused history, examination priorities, investigations, emergency and definitive management.
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Brief (to candidate)
You will assess a patient with a presentation consistent with Intra-Abdominal Infection & Peritonitis.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
Intra-abdominal infection (IAI) and peritonitis are time-critical emergencies that span two very different diseases. Primary peritonitis — spontaneous bacterial peritonitis (SBP) — is infection of cirrhotic ascites without an intra-abdominal source, presenting subtly (fever, abdominal pain, hepatic encephalopathy, renal failure) and treated medically with cefotaxime/ceftriaxone plus IV albumin (the ascitic neutrophil count over 250 cells per mm³ is diagnostic). Secondary peritonitis is polymicrobial contamination of the peritoneum from a perforated or translocating hollow viscus (perforated peptic ulcer, appendicitis, diverticulitis, ischaemic bowel, post-operative leak, trauma) and is a sur
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 | Sudden severe abdominal pain with peritonism (rigidity, guarding, rebound) and s |
| Safety | Cirrhotic with ascites and fever, abdominal pain, encephalopathy or renal failur |
| Safety | Ascitic neutrophil count over 250 cells per microL — SBP; treat immediately, eve |
| 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.