Horinouchi H, Kumamoto T, Fujimoto S, Ueyama H, Sannomiya K, Tsuda T
Third Department of Internal Medicine, Oita Medical University.
Rinsho Shinkeigaku. 2000 Jun;40(6):586-90.
A 22-year-old man developed unconsciousness, severe quadriplegia and muscle atrophy, and had markedly elevated serum creatine kinase levels after using the high-dose steroid and nondepolarizing neuromuscular blocking agents during the course of sepsis and DIC. On neurological examination, he was lethargic. The patient had generalized muscle weakness and wasting, and diminished deep tendon reflexes. He weakly responsed to painful stimuli on the legs. The motor nerve conduction study demonstrated decreased CMAP (compound muscle action potential) amplitudes. Motor and sensory nerve conduction velocities and their distal latencies were normal. Muscle biopsy revealed marked muscle fiber atrophy predominantly in type 2 fibers and numerous basophilic and a few necrotic fibers. Some atrophic fibers had decreased to absent myosin adenosine triphosphatase activity in their center. Accordingly, he was diagnosed as having acute quadriplegic myopathy (AQM), which has been reported mainly in Western countries. The mechanism of muscle fiber degradation in this myopathy is still unknown. On immunohistochemical analysis to our patient, enzyme activities of various proteases such as calpain, cathepsin B, and proteasomes were increased in the sarcoplasm, especially in the atrophic fibers. We suggest that lysosomal cathepsin, nonlysosomal calpain, and ATP-ubiquitin-proteasome proteolytic pathways participate in muscle fiber degradation in AQM.
一名22岁男性在脓毒症和弥散性血管内凝血病程中使用大剂量类固醇和非去极化神经肌肉阻滞剂后，出现意识丧失、严重四肢瘫痪和肌肉萎缩，血清肌酸激酶水平显著升高。神经系统检查时，他嗜睡。患者有全身肌肉无力和萎缩，腱反射减弱。他对腿部的疼痛刺激反应微弱。运动神经传导研究显示复合肌肉动作电位（CMAP）波幅降低。运动和感觉神经传导速度及其远端潜伏期正常。肌肉活检显示明显的肌纤维萎缩，主要为2型纤维萎缩，有大量嗜碱性纤维和少量坏死纤维。一些萎缩纤维中央的肌球蛋白三磷酸腺苷酶活性降低至消失。因此，他被诊断为急性四肢瘫痪性肌病（AQM），该病主要在西方国家有报道。这种肌病中肌纤维降解的机制仍不清楚。对我们的患者进行免疫组织化学分析时，发现肌浆中各种蛋白酶如钙蛋白酶、组织蛋白酶B和蛋白酶体的酶活性增加，尤其是在萎缩纤维中。我们认为溶酶体组织蛋白酶、非溶酶体钙蛋白酶和ATP-泛素-蛋白酶体蛋白水解途径参与了AQM中的肌纤维降解。
