OSCE — Rhabdomyolysis

Brief (to candidate)

You will assess a patient with a presentation consistent with rhabdomyolysis. You have 8 minutes to take a focused history, outline examination, investigations, and management including red flags.^[1]

Clinical context

Rhabdomyolysis is skeletal muscle breakdown with release of myoglobin, creatine kinase, potassium and phosphate into the circulation. Stahl's recommended mild definition is acute muscle weakness, myalgia and swelling plus CK over 1000 IU/L or over 5 times ULN; myoglobinuria and AKI mark severe disease. The most common complication is myoglobinuric AKI; early death in extensive disease arises from hypovolaemic shock, hyperkalaemia, acidosis and myoglobinuric AKI. Causes in a 475-patient cohort were led by illicit drugs, alcohol and prescribed drugs (46%).^[1][2][7]

Candidate tasks

1. Clarify onset, severity, associated features, and red-flag symptoms.
2. State focused examination priorities (ECG, compartments, urine colour, volume status).
3. List first-line investigations and the McMahon composite of RRT or in-hospital death.
4. Give immediate resuscitation steps.
5. Outline definitive management with sourced fluid and hyperkalaemia regimens.
6. Name complications and disposition.
7. Mention one special-population modifier (elderly long-lie; crush disaster).^[7][10]

Examiner checklist

^{[2] [7] [10] [17] [18]}

Model outline

Lead with life threats: hyperkalaemic ECG changes and crush/compartment reperfusion. Start fluid before waiting for a second CK. Use IV calcium salts only for ECG changes or potassium at or above 6.5 mmol/L. Do not start dialysis on the CK number. Decompress when diastolic minus compartment pressure falls under 30 mmHg. McMahon: composite RRT or death 19.0% overall (8.0% RRT, 14.1% died); compartment syndrome 41.2%.^{[4][7][9][10][17][18]}

References8ShowHide

1. [1]Stahl K, Rastelli E, Schoser B A systematic review on the definition of rhabdomyolysis J Neurol, 2020.PMID 30617905
2. [2]Cervellin G, Comelli I, Lippi G Rhabdomyolysis: historical background, clinical, diagnostic and therapeutic features Clin Chem Lab Med, 2010.PMID 20298139
3. [4]Veenstra J, Smit WM, Krediet RT, et al. Relationship between elevated creatine phosphokinase and the clinical spectrum of rhabdomyolysis Nephrol Dial Transplant, 1994.PMID 7970089
4. [7]Better OS, Abassi ZA Early fluid resuscitation in patients with rhabdomyolysis Nat Rev Nephrol, 2011.PMID 21587227
5. [9]Petejova N, Martinek A Acute kidney injury due to rhabdomyolysis and renal replacement therapy: a critical review Crit Care, 2014.PMID 25043142
6. [10]McMahon GM, Zeng X, Waikar SS A risk prediction score for kidney failure or mortality in rhabdomyolysis JAMA Intern Med, 2013.PMID 24000014
7. [17]Geldermann N, Dzimiera J, Fischer H, et al. Acute hyperkalaemia in emergency care: evidence-based approaches Emerg Med J, 2026.PMID 41506858
8. [18]McQueen MM, Court-Brown CM Compartment monitoring in tibial fractures. The pressure threshold for decompression J Bone Joint Surg Br, 1996.PMID 8898137