MBBS OSCE · General Medicine
OSCE — Motor Neuron Disease (ALS)
Eight-minute OSCE station on Motor Neuron Disease (ALS): 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 Motor Neuron Disease (ALS).
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
Motor neuron disease (MND/ALS) is a progressive neurodegenerative disorder that destroys BOTH upper motor neurons (UMN: spasticity, hyperreflexia, Babinski sign) AND lower motor neurons (LMN: weakness, wasting, fasciculations) while sparing sensation, eye movements and sphincter function. Annual incidence is about 2 per 100,000, peak onset 55 to 65 years, male-to-female ratio 1.5 to 1. About 10 percent is familial (C9orf72, SOD1, TARDBP, FUS). Diagnosis is clinical (Gold Coast 2020 criteria), supported by EMG (active denervation with chronic reinnervation across regions) and MRI to exclude mimics. Treatment is multidisciplinary: riluzole 50 mg twice daily extends median survival by about 2 t
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 | Progressive painless asymmetric weakness with wasting AND fasciculations AND bri |
| Safety | Progressive dysarthria and dysphagia with tongue wasting and fasciculations — bu |
| Safety | Respiratory symptoms (orthopnoea, morning headaches, daytime somnolence) in know |
| 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.