Causes and outcome of rhabdomyolysis in patients admitted to medical wards in the Prince of Wales Hospital

Abstract

BACKGROUND: Rhabdomyolysis with a marked elevation of serum creatine kinase (CK) can be caused by various conditions. Acute kidney injury (AKI) is a potential complication of severe rhabdomyolysis and leads to a rapid increase in serum creatinine. METHODS: This study was performed to identify medical cases diagnosed with rhabdomyolysis and to examine the likely causes. Patients diagnosed with rhabdomyolysis during admission to the medical wards of Prince of Wales Hospital (PWH) in Hong Kong from January 1, 2004 to May 31, 2012 were identified by searching computer records. Details of hospital admissions were retrieved, and the underlying causes of the rhabdomyolysis and clinical outcomes were analyzed. RESULTS: There were 95 Chinese patients with a median age of 72 years (range, 22-92 years) assigned a diagnosis of rhabdomyolysis. A mild degree of AKI was defined as an increase of serum creatinine more than 20% above the baseline value before onset of acute illness and with the highest creatinine greater than 120 µmol/L. Mild AKI was identified in 63 patients. Rhabdomyolysis appeared to contribute to a fatal outcome in eight patients who had multiple preexisting morbidities. The maximum CK had a median value of 9,829 U/L (range, 472-258,100 U/L). Twelve patients with peak CK levels <10× the upper limit of normal (ULN) may not have had rhabdomyolysis by this standard definition. Of the remaining 83 patients with maximum CK values >10× the ULN, the most common contributing factors were trauma (n=19) and infection (n=17). Other common underlying causes included drug abuse (heroin and alcohol) and ischemia/immobility. CONCLUSIONS: Most patients recovered with appropriate medical interventions and had a median hospital stay of 13 days. One patient was thought to have drug-related rhabdomyolysis due to taking bezafibrate during an episode of renal impairment.