原发性肉碱缺乏致脂质沉积性肌病的临床与病理特点

Clinical and pathological features of lipid storage myopathy caused by primary carnitine deficiency

目的分析原发性肉碱缺乏致脂质沉积性肌病(LSM)的临床与病理特点。方法回顾性分析4例可能LSM患者的临床资料。结果本组患者为亚急性或慢性起病,主要表现为近端肌无力,疲劳不能耐受;血清肌酶有不同程度的升高;肌电图示肌源性损害;病理检查示肌纤维内可见大量细小空泡和裂隙形成;MGT染色无破碎红纤维,油红O染色显示空泡为大量脂滴充填;受累纤维以Ⅰ型纤维为主。电镜证实肌纤维内脂滴堆积,可伴有线粒体的轻度增多。改善能量和糖皮质激素治疗有效。结论原发性肉碱缺乏致LSM是一种以易疲劳和肌无力为主要临床表现的脂质代谢障碍性肌病,病理改变以肌纤维内脂滴堆积为主,一般不伴有线粒体结构的明显异常。糖皮质激素治疗可获得良好疗效。

Objective To analyze the clinical and pathological features of lipid storage myopathy （LSM） caused by primary carnitine deficiency （ CD ）. Methods The clinical data of 4 cases of possible LSM caused by primary CD were analyzed retorspectively. Results The clinical features of the 4 patients were subacute or chronic onset, proximal muscle weakness and exercise intolerance. Elevated levels of creatases were measured in serum and myogenic damage was found by EMG examination. Frozen sections of muscle biopsy samples showed many fibers contained numerous vacuoles which was stained by oil red O. No ragged red fiber （RRF） was seen in MGT stain. Type I fibers were more severely affected. In electron microscopy, the prominent abnormality was the presence of excessive amounts of fatty droplets in muscle fibers and subsarcolemmal regions with mild increased mitochondria. Treatment with glucocorticoid and energy supplement had been clinically beneficial. Conclusions Fatigue and muscle weakness are prominent manifestations in LSM caused by primary CD. The main changes are accumulation of lipid droplets in muscle specimen without prominent abnormality in structure in mitochondria. Good clinic effect may be caused by therapy with glucocorticoid.