MBBS OSCE · Nephrology
OSCE — Hyperkalaemia
Eight-minute OSCE station on Hyperkalaemia: 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 Hyperkalaemia. You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags. [1][2]
Clinical context
Hyperkalaemia is a serum potassium at or above 5.5 mmol/L (Lehnhardt; UKKA/ERC). UKKA bands: mild 5.5-5.9, moderate 6.0-6.4, severe at or above 6.5 mmol/L. Exclude pseudohyperkalaemia (haemolysis, tourniquet, fist-clenching, thrombocytosis, leucocytosis) in the well patient with a normal ECG. Causes cluster into impaired excretion (CKD, ACEi/ARB/MRA, NSAIDs, Addison), transcellular shift, and increased load. ECG may show peaked T, PR prolongation, lost P, wide QRS, sine wave. [1][2][4]
Candidate tasks
- Clarify onset, severity, associated features, and red-flag symptoms.
- State focused examination priorities (ECG first).
- List first-line investigations.
- Give immediate resuscitation steps with sourced doses.
- Outline definitive management.
- Name complications and disposition.
- Mention one special-population modifier (dialysis, heart failure on RAAS, child). [2]
Examiner checklist
| Domain | Pass behaviours |
|---|---|
| Definition | K+ at or above 5.5 mmol/L; UKKA mild/moderate/severe bands |
| Assessment | ECG before history if unstable; looks for peaked T / wide QRS / sine wave |
| Investigations | Repeat sample or ABG K+; glucose; renal function; cortisol if Addisonian |
| Emergency care | Calcium if ECG abnormal (UKKA 6.8 mmol equivalent or Long 10 mL 10% gluconate); insulin 10 units with glucose; salbutamol adjuvant |
| Definitive care | Stop K-retaining drugs; binder or dialysis; does not offer SPS as first-line emergency removal |
| Safety | Does not delay calcium for a repeat sample when the QRS is wide |
| Safety | Does not invent hydrocortisone 100/200 mg; says parenteral hydrocortisone without waiting for cortisol if Addisonian |
| Communication | Clear plan, glucose monitoring after insulin, escalation to dialysis |
Model outline
Lead with working diagnosis and life threats. If the ECG is already abnormal, IV calcium now (does not lower K+). Then insulin 10 units with glucose (UKKA 25 g; Harel 50 g with 10 units) and nebulised salbutamol 10-20 mg as adjuvant. Arrange removal. Repeat the sample in the well normal-ECG patient before committing them to the ladder. Addisonian features: parenteral hydrocortisone, rehydrate, do not wait for cortisol. [2][3][5]
References5ShowHide
- [1]Lehnhardt A, Kemper MJ. Pathogenesis, diagnosis and management of hyperkalemia Pediatr Nephrol, 2011.PMID 21181208
- [2]Alfonzo A, Harrison A, Baines R, Chu A, Mann S, MacRury M. Clinical Practice Guidelines: Treatment of Acute Hyperkalaemia in Adults UK Kidney Association (Renal Association), 2020.Source
- [3]Long B, Warix JR, Koyfman A. Controversies in Management of Hyperkalemia J Emerg Med, 2018.PMID 29731287
- [4]Meng QH, Wagar EA. Pseudohyperkalemia: A new twist on an old phenomenon Crit Rev Clin Lab Sci, 2015.PMID 25319088
- [5]Dineen R, Thompson CJ, Sherlock M. Adrenal crisis: prevention and management in adult patients Ther Adv Endocrinol Metab, 2019.PMID 31223468