MBBS OSCE · Emergency & Toxicology
OSCE — Beta-Blocker & Calcium-Channel Blocker Overdose
Eight-minute OSCE station on Beta-Blocker & Calcium-Channel Blocker Overdose: 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 Beta-Blocker & Calcium-Channel Blocker Overdose.
You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.
Clinical context
Beta-blocker (BB) and calcium-channel blocker (CCB) overdoses are two of the most lethal prescription drug poisonings and are taught together because they produce an overlapping toxidrome — bradycardia, hypotension, AV conduction block and cardiogenic shock refractory to standard ACLS — and share an overlapping antidote ladder (IV calcium, high-dose insulin euglycaemia therapy, glucagon, vasopressors, lipid emulsion, pacing, ECMO). Beta-blockers antagonise beta-adrenergic G-protein-coupled receptors -> reduced cAMP/PKA -> reduced L-type calcium-channel opening -> negative inotropy, chronotropy and dromotropy; lipophilic agents (propranolol, metoprolol, carvedilol) cross the blood-brain barri
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 | Bradycardia + hypotension + AV block after BB or CCB ingestion — severe cardioto |
| Safety | Hyperglycaemia + metabolic acidosis in a bradycardic, hypotensive overdose patie |
| Safety | Sustained-release verapamil/diltiazem ingestion — delayed and prolonged severe 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.