- **myoglobin** is nephrotoxic - rapidly excreted in urine - rapidly metabolised to bilirubin # causes - trauma - drugs - toluene - phencylidine - amphetamines - cocaine - heroin - theophylline - simvastatin (mild usually) - arsenic - EtOH withdraw - toxins - [[Snakebite]] - rarely spider envenomation - NMS - accidental [[Heat-related illness|hyperthermia]] - frostbite - severe [[Serotonin Syndrome]] - prolonged [[Seizures]] - inflammatory myopathies - [[thyrotoxicosis|thyroid storm]] # assessment - tender swollen muscles - CK > 1000 (usually >10,000 - 100,000) - myoglobinuria - urine dark red/brown when serum levels > 100mg/dL - positive for "blood" when myoglobin concentrations 0.5 - 1 mg/dL but no RBCs in microscopy **Risk of renal impairment**: - urine myoglobin concentration > 20,000 mcg/L # Treatment - haemodialysis if anuric - treat [[hyperkalemia]] as priority - don't give suxamethonium - maintain high urinary flow > 2 mL/kg/h - IVF 1L/H for first 4 hours - consider *alkalising urine pH > 7* (myoglobin higher renal toxicity at lower pH (50 mmol/H [[HCO3 therapy|NaHCO3]] - cannot mix Ca2+ with HCO3 infusion due ot precipitate formation - monitor for [[Hypocalcemia]] and treat as appropriate - treat underlying cause - eg termal regulation, tx seizures, fasciotomy, abx # disposition - usually hospital admission - exertional rhabdo without heat stroke usually benign course even when CK > 25,000, can go to SSU