Muscle Biopsy in Exertional Heatstroke Patients: Metabolic Myopathy and Thpe Ⅱ Fibres Predominance are Susceptible to Exertional Heatstroke

肌肉切片研究中具有第二型肌纖維顯著或代謝性肌病變者有高傾向造成運動性熱中暑疾病

許燿東(Yaw-Don Hsu) ； 李偉華(Wei-Hwa Lee) ； 張民基(Ming-Key Chang) ； 曹汶龍(Wen-Long Tsao) ； 謝善德(Shang-Der Shieh) ； 林裕峰(Yuh-Feng Lin)

《Journal of Medical Sciences》 17卷2期 (1996/10) Pp. 77-90

摘要

This work is focused on exertional heat stroke (ExHS), with emphasis on predisposing factors in skeletal muscle damage, clinical observations, diagnosis, and recovery. Recruits, individuals of young active population, are at risk to contract in exertional heat stroke. Severe skeletal muscle damage is usually seen in this disorder. The present study was undertaken to evaluate the morphological alterations of skeletal muscle in heat disorder as a clue to understand the pathogenesis of muscle damage. Thirty-seven military recruits with ExHS hospitalized at the Tri-Service General Hospital, Taiwan. All subjects were men, and the age at onset was young, 19 to 23 years old. In clinical observation, we found high peak value of serum creatine phosphokinase (CPK) level, 167 to 870,500 U/L (11,260±18,860 U/L) in ExHS patients, and noted cliical features of muscle weakness and myalgia. Muscle biopsy was taken from the vastus lateralis of each ExHS patient. Characteristic findings of morphological alteration of rhabdomyolysis in ExHS patients included necrotic fibres, and occasional hypercontracture fibres. One case had ragged-red fibres, and one case was glycolytic disorder. Another interesting finding, type II fibre predominance, was observed in 22 ExHS patients. Fibre types analysis marked difference in ExHS patients corresponded to normal control group (N=15), p＜0.001. ExHS patients with type II fibre predominance had a tendency of developing rhabdomyolysis (χ^2=6.84, p＜0.01). In addition, the correlation between peak serum CPK level and percentage of type II fibres in 37 ExHS patients demonstrated positive correlation (t=2.9, r=o.44,p＜0.01). Five ExHS patients had delay onset of soreness with unknown etiology. In conclusion, type II fibre predominance and metabolic myopathies in recruits is susceptible to ExHS.

關鍵字

肌溶解症 ； 運動性熱中暑 ； 第二型肌纖維顯著

並列摘要

This work is focused on exertional heat stroke (ExHS), with emphasis on predisposing factors in skeletal muscle damage, clinical observations, diagnosis, and recovery. Recruits, individuals of young active population, are at risk to contract in exertional heat stroke. Severe skeletal muscle damage is usually seen in this disorder. The present study was undertaken to evaluate the morphological alterations of skeletal muscle in heat disorder as a clue to understand the pathogenesis of muscle damage. Thirty-seven military recruits with ExHS hospitalized at the Tri-Service General Hospital, Taiwan. All subjects were men, and the age at onset was young, 19 to 23 years old. In clinical observation, we found high peak value of serum creatine phosphokinase (CPK) level, 167 to 870,500 U/L (11,260±18,860 U/L) in ExHS patients, and noted cliical features of muscle weakness and myalgia. Muscle biopsy was taken from the vastus lateralis of each ExHS patient. Characteristic findings of morphological alteration of rhabdomyolysis in ExHS patients included necrotic fibres, and occasional hypercontracture fibres. One case had ragged-red fibres, and one case was glycolytic disorder. Another interesting finding, type II fibre predominance, was observed in 22 ExHS patients. Fibre types analysis marked difference in ExHS patients corresponded to normal control group (N=15), p＜0.001. ExHS patients with type II fibre predominance had a tendency of developing rhabdomyolysis (χ^2=6.84, p＜0.01). In addition, the correlation between peak serum CPK level and percentage of type II fibres in 37 ExHS patients demonstrated positive correlation (t=2.9, r=o.44,p＜0.01). Five ExHS patients had delay onset of soreness with unknown etiology. In conclusion, type II fibre predominance and metabolic myopathies in recruits is susceptible to ExHS.

並列關鍵字

rhabdomyolysis ； exertional heatstroke ； type Ⅱ fibre predominance