Snapshot A 26-year-old woman has just finished running a full marathon. She did not stop as often as she would have liked for water to rehydrate during her 26.2 mile run. She reports feeling lightheaded and has mild muscle soreness. When she went to use the restroom, she noticed that her urine was dark – almost like tea. At an urgent care clinic, her serum creatine kinase is found to be elevated. An ECG is shown here. Introduction Clinical definition skeletal muscle breakdown and necrosis releases intracellular contents of the cells into circulation causes severe complications including acute kidney injury, compartment syndrome, cardiac arrest, or respiratory failure Epidemiology Risk factors intense physical exercise under heat or humidity diuretic abuse marathon running Etiology Common associations trauma crush injury alcohol abuse cocaine abuse statins and fibrates together neuroleptic malignant syndrome Pathogenesis mechanism muscle cell injury causes intracellular contents to be released including: potassium myoglobin uric acid sarcoplasmic contents creatine kinase alanine aminotransferase (ALT) aspartate aminotransferase (AST) cocaine-induced rhabdomyolysis prolonged vasoconstriction can lead to ischemia and necrosis of muscle cells acute kidney injury high levels of myoglobin precipitates in kidneys and cause tubular obstruction metabolites of myoglobin also directly causes damage to tubules Presentation Symptoms primary symptoms classic triad muscle pain weakness and swelling of muscle tea-colored urine (myoglobinuria) nausea emesis oliguria or anuria may be asymptomatic Physical exam fever tachycardia muscle weakness Studies Labs ↑ serum creatine kinase (CK) ↑ serum myoglobin because of its short half-life they are not as sensitive as CK ↑ serum creatinine electrolyte abnormalities ↑ potassium ↑ phosphate ↓ calcium (most common disturbance) ↑ uric acid ↑ liver function tests Urine dipstick myoglobinuria Urinalysis protein brown casts uric acid crystals red blood cells Electrocardiogram (ECG) monitor for cardiac arrhythmias from electrolyte abnormalities first step in evaluating a patient with suspected rhabdomyolysis Diagnostic criteria elevated serum CK Differential Hemolysis causing hemoglobinuria (dark urine) normal CK Treatment Conservative fluid hydration and mannitol indications for all patients to help treat or prevent acute kidney injury Medical sodium bicarbonate indications to alkalinize the urine insulin and glucose indications if rhabdomyolysis causes hyperkalemia calcium gluconate if peaked T-waves on EKG Complications Acute kidney injury Cardiac arrest from hyperkalemia Prognosis generally good with early detection, supportive care, and careful monitoring