Occult Elevation of CK as a Manifestation of Rhabdomyolysis in the Elderly

OBJECTIVE: To evaluate the incidence, etiology and clinical course of rhabdomyolysis in hospitalized elderly patients. DESIGN: Retrospective case series. SETTING: Acute geriatric department of a university-affiliated teaching hospital. PATIENTS: Twenty-three patients who fulfilled our criteria of rhabdomyolysis. Criteria for inclusion were the finding of elevated serum creatine kinase of five-fold or greater above the upper reference limit and greater than 97% MM isoenzyme. RESULTS: In a 3-year period 23 patients out of 2,870 admissions fulfilled the criteria for rhabdomyolysis, an incidence rate of 0.8%. Diseases or insults associated with rhabdomyolysis were, in order of frequency, acute immobilization, infectious disease, cerebrovascular accident, hyperosmolar state, hyponatremia, hypernatremia, hypothermia, and a fall. Twenty-two patients recovered from the acute illness; one patient died from respiratory failure. Seventeen patients had renal failure (serum creatinine greater than 180 mumol/L), none necessitating dialysis. Serum creatinine always declined following recovery. CONCLUSION: Elevation of CK with few other clinical features of rhabdomyolysis is common in admissions to a geriatric service. It is due to complete immobilization resulting from acute illness. Renal failure is mild and reversible, and the prognosis for recovery is excellent.