Relationship between elevated creatine phosphokinase and the clinical spectrum of rhabdomyolysis

The incidence, causes and complications of severe rhabdomyolysis (creatine phosphokinase (CK) > or = 5000 U/l) were studied during a 7-year study period in a large university hospital population. This condition was present in 0.074% of all admitted patients. The mortality in the study group (n = 93) was 32% and the incidence of acute renal failure (ARF) 51%. Ischaemia was the most frequent cause, and drugs, alcohol and/or coma were the second most common cause of severe rhabdomyolysis. Patients with rhabdomyolysis due to ischaemia were older, had ARF more often, and also had the highest mortality. Hyperkalaemia (potassium > or = 5.5 mmol/l) occurred in 13% of the patients, and all of them had or developed an impaired renal function. Hypocalcaemia (calcium < or = 2.00 mmol/l) was found in 41%. The incidence of ARF and electrolyte disturbances was higher in patients with CK levels exceeding 15,000 U/l. Mortality was significantly higher in patients with ARF. Plasma concentrations of potassium and calcium correlated better with the severity of renal failure than with the maximal height of plasma CK.