MBBS OSCE · General Medicine
OSCE — Myasthenia Gravis
Eight-minute OSCE station on Myasthenia Gravis: 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 Myasthenia Gravis.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
Myasthenia gravis (MG) is a B-cell-mediated autoimmune disorder of the postsynaptic neuromuscular junction in which autoantibodies damage or block the muscle acetylcholine receptor (or related proteins such as MuSK and LRP4), producing fluctuating, fatigable weakness that worsens with sustained activity and improves with rest. The hallmark is ocular involvement (ptosis, diplopia) in about half of patients, often spreading to bulbar (dysphagia, dysarthria, nasal voice), proximal limb, axial and respiratory muscles. Antibodies are positive in anti-AChR in 85 percent, anti-MuSK in 5 to 8 percent, anti-LRP4 in 2 to 5 percent, and 5 to 8 percent are seronegative. Diagnosis combines the clinical p
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 | Fatigable ptosis or diplopia worsening with sustained upgaze — myasthenia gravis |
| Safety | Respiratory muscle weakness with FVC under 20 mL/kg or falling rapidly — myasthe |
| Safety | Bulbar weakness (dysphagia, nasal voice, weak cough) — aspiration risk; airway p |
| 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.