儿童进行性肌营养不良的临床及病理特征

Clinical and pathological features in children with progressive muscular dystrophy

目的探讨进行性肌营养不良(PMD)患儿的临床及病理特征,为该病的早期诊断提供帮助。方法对99例PMD住院患儿的临床表现、发病年龄、家族史、肌酶、肌电图及肌肉病理学特点进行全面性回顾分析。结果 (1)99例患儿起病年龄6个月至14.5岁(4.7±3.1)岁。11例有明确家族史(11%)。26例(26%)有误诊史。(2)所有患儿就诊时均有肌无力表现,66例肌肉萎缩和/或肥大(67%)。(3)所有患儿CK均明显升高,其中2岁-组51例,CK均值为9965±8876 U/L,7-15岁组48例,均值为5110±4498 U/L,组间比较差异有统计学意义(P<0.01)。(4)肌电图检查显示肌源性损害54例(82%);神经源性损害10例(15%)。(5)光镜显示同时存在肌纤维萎缩和肥大,可见透明变性、颗粒变性等。电镜显示肌纤维粗细不等,部分萎缩或肥大。肌细胞核内移,肌膜下肌丝轻度溶解消失,肌纤维内有肌溶灶散在,糖原颗粒及线粒体增加,肌浆网轻度增生并扩张,少数肌纤维坏死。结论双下肢无力仍然是发现PMD和就诊的主要原因,CK是诊断PMD的主要实验室依据。PMD肌电图早期以肌源性损害为主,晚期可合并神经源性损害。PMD误诊率高。光镜和电镜病理学检查是PMD确诊的主要方法。

Objective To investigate the clinical and pathological features of progressive muscular dystrophy （PMD） in children and to provide help for the early and accurate diagnosis of PMD. Methods Retrospective analysis was performed on the clinical data of 99 hospitalized children with PMD, including clinical manifestations, age of onset, family history, creatase, electromyogram （EMG） and pathological changes of muscles. Results Of the 99 children with PMD, the age of onset was 0.5-14.5 （4.7~3. l） years. Eleven cases （11%） had a family history of PMD. Twenty-six （26%） were misdiagnosed as other diseases. All patients presented with muscle weakness when seeing the doctor, and 66 （67%） of them had muscle atrophy and/or hypertrophy. All patients had elevated creatine kinase （CK） levels. The 2-7-year-old group （n=51） had a mean CK level of 9965±8876 U/L, and the 7-15-year-old group （n=48） had a mean CK level of 5110±4498 U/L, with a significant difference between the two groups （P〈0.01）. The EMG examination performed on 66 patients showed that 54 cases （82%） had myogenic damage and 10 cases （15%） had neurogenic damage. Light microscopy revealed coexistence of atrophy and hypertrophy of muscle fibers, hyaline degeneration and granular degeneration. Electron microscopy showed that muscle fibers were different in thickness, some atrophic or hypertrophic; muscle cell nuclei moved inwardly, myofilaments dissolved and disappeared mildly under the sarcolemma, there were scattered melting lesions within muscle fibers, the numbers of glycogen granules and mitochondria increased, mild hyperplasia and expansion of sarcoplasmic reticulum were seen, and a small number of muscle fibers had necrosis. Conclusions Weakness of both lower extremities remains the main reason for PMD patients seeing the doctor. CK is the main laboratory indicator for diagnosis of PMD. PMD is mainly manifested as myogenic damage in the early stage and may be accompanied by neurogenic damage in the late stage, according to the EMG examination. With a high misdiagnosis rate, PMD may be misdiagnosed as many other diseases. Pathological examination under light microscope and electron microscope is the main means for confirming a PMD diagnosis.