Rhabdomyolysis
- major trauma patients, crush injuries and 'long lie' patients who have not moved for some time possibly due to intercurrent medical condition and drug and alcohol abuse especially when associated with prolonged seizure activity. Consider other medical causes such as viral myositis, connective tissue disorders and drug reactions (eg malignant hyperthermia)
- myoglobin levels in blood and urine often have returned to normal within 24/24 so CK levels are more helpful, often peaking around 3/7
- creatine kinase (CK) level of more than 5000U/L is considered to be an absolute indication for hospitalization and vigorous IV hydration until consistent levels <1000U/L
- treatment aimed at preventing precipitation of myoglobin in tubules which is especially likely in acidic urine
- prompt IV saline is paramount to achieve diuresis of at least 2-3ml/kg/hr
- NaHCO3 - may be useful to - 1.alkalinise urine to minimise myoglobin breakdown, 2. reduce crystallisation of uric acid BUT may exacerbate hypocalcaemia.
- IV hydration with enhanced urine output is probably sufficient alone. Trials have NOT supported benefit of NaHCO3 - no reproducible benefit over saline alone as well as risk of worsening hypocalcaemia
- other treatments aimed at correcting electrolyte imbalances and surgery may be required in cases of compartment syndrome
Labs
- hypocalcaemia secondary to hyperphosphataemia and possibly also precipitation in necrotic muscle may result, hypercalcaemia is possible
- hyperkalaemia, hyperuricaemia
- other Muscle enzymes raised: LDH, AST and aldolase
- DIC rarely