Causes
Trauma
Drugs and Toxins
- Statins
- Alcohol
- Ecstasy, cocaine, amphetamines
- Heroin and methadone
- Steroids
- Propofol (infusion ± inotropes)
Snake bite (very common in Ireland!)
Neuroleptic malignant syndrome
Infections
- Coxsackie virues
- EBV
- Influenza
- Tetanus
Metabolic
- Hypokalaemia, ↓ phosphate
- Myositis
- Malignant hyperpyrexia
Inherited disorders
- McArdle's / Tarui disease (glucose metabolism)
- Duchenne's muscular dystrophy
Complications
- Hyperkalaemia (arrhythmias and cardiac arrest)
- Hypocalcaemia (worsened by hyperphosphataemia)
- Hepatic abnormalities – but AST may be high representing muscle AST
- AKI from precipitation and obstruction of renal tubules by myoglobinuria and hypovolaemia
- DIC
- Pooling of fluid in the damaged muscle = hypovolaemia ±compartment syndrome
Investigations
- VBG
- U&E
- FBC and coag (DIC?)
- Urine microscopy (casts?)
- LFTs
ECG changes
- Hyperkalaemic changes - ↑T, ↓/broad P, ↑QRS, Sine wave, AV dissociation, VF/VT
- Tachycardia
- Atrial fibrillation
- ↑ QT
Management
Find / treat the cause
Increase renal elimination
- Fluids - aiming to maintain UO > 200ml/hr
- IV sodium bicarbonate (dilute please) to alkalinise urine to pH >6.5, to stabilise a less toxic form of myoglobin
- Dialysis
- If UO inadequate then diuretics eg mannitol and furosemide can be used