Expansion
Myoglobin, potassium, phosphate and creatine kinase are released into the circulation
Expansion
Released from damaged muscle
- Myoglobin: nephrotoxic, causing acute kidney injury by tubular obstruction, direct toxicity and renal vasoconstriction
- Potassium: hyperkalaemia, often severe and early
- Phosphate: hyperphosphataemia, causing hypocalcaemia by precipitation
- Creatine kinase: the diagnostic marker, typically above 5 times normal and often in the tens of thousands
- Urate and lactate
Later, calcium is released back from damaged muscle, causing rebound hypercalcaemia during recovery, which is why calcium should be given cautiously.
Causes: crush injury, prolonged immobility, seizures, extreme exertion, malignant hyperthermia, neuroleptic malignant syndrome, statins, alcohol, and compartment syndrome.
Management
- Aggressive intravenous fluid, the mainstay, aiming for a good urine output
- Treat hyperkalaemia
- Monitor for compartment syndrome, which can be both cause and consequence
- Urinary alkalinisation is of debated benefit