MBBS OSCE · General Surgery
OSCE — Abdominal Aortic Aneurysm
Eight-minute OSCE station on Abdominal Aortic Aneurysm: 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 Abdominal Aortic Aneurysm.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
Abdominal aortic aneurysm (AAA) is a permanent, localised dilation of the abdominal aorta to 3 cm or more (or 1.5 times the expected normal diameter), with over 90% infrarenal. Most are asymptomatic until rupture. Risk: male sex, age over 65, smoking (the dominant modifiable factor), family history, hypertension. Screening: one-off ultrasound for men at 65 (NHS AAA Screening Programme); USPSTF for men 65 to 75 who ever smoked. Surveillance thresholds: under 3 cm normal; 3.0 to 4.4 cm yearly; 4.5 to 5.4 cm every 3 months; over 5.5 cm refer for elective repair (open or EVAR). Rupture triad: severe abdominal/back/flank pain plus hypotension plus a pulsatile abdominal mass (complete in only half
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 | Severe abdominal, back or flank pain with hypotension and a pulsatile abdominal |
| Safety | AAA over 5.5 cm diameter - elective repair indicated; rupture risk rises steeply |
| Safety | Rapidly expanding AAA (over 0.5 cm in 6 months, or over 0.7 cm in a year for sma |
| 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.