Clinicopathological analysis on eight patients with rhabdomyolysis caused by exertional heat stroke

Abstract

Objective To investigate the clinicopathological features and the pathogenesis of rhabdomyolysis caused by exertional heat stroke. Methods Eight patients including 6 military soldiers and 2 physical exercisers trained under high temperature environment were enrolled into this study.Their clinical manifestations were compatible with the diagnostic standard of exertional heat stroke.Consecutive blood biochemistry tests were performed in all patients，and electromyography and muscle biopsy in 3 cases. Results Eight patients were all male，with average age of 27.4 years old.The main clinical characteristics included myalgia in 4 patients，muscle weakness in 2 patients，fever in 5 patients，and tea-colored urine in 3 patients.One patient had acute renal failure，and 2 patients developed multiple organ failure syndromes and disseminated intravascular coagulation.One muscle biopsy done in the third day after the onset showed obvious muscle necrosis without inflammatory infiltrates，while the other 2 muscle biopsy done 2 weeks after the onset showed muscle necrosis companied by inflammatory phagocytic response.Six patients full recovered，1 patient partially recovered and one patient died. Conclusions Rhabdomyolysis caused by exertional heat stroke predominantly occurred in males.The main clinical features include muscle pain，weakness，significantly elevated serum creatine kinase and myoglobin level and myoglobinuria.Muscle pathology indicated muscle necrosis in the early stage and accompanied inflammatory infiltrates in the late stage.Most patients will get recovered with prompt diagnosis and treatment while the severe cases can be life-threatening. Key words: Heat stroke; Rhabdomyolysis; Muscle fibers; Necrosis; Biopsy