“Give me strength” – inflammatory muscle disease in children

Juvenile dermatomyositis is the most common idiopathic inflammatory myopathy of childhood. Management focuses on early aggressive suppression of inflammation to induce sustained remission and prevent complications such as muscle contractures or calcinosis. Advances in diagnostic modalities and treatment have led to improved mortality and morbidity, but long-term risks remain significant. Early disease recognition with appropriate referral and management by a specialist multidisciplinary team is crucial. This review focuses on juvenile dermatomyositis including differential diagnosis from other conditions causing muscle weakness in children.     

A new method for isolation of cardiac myocytes by percutaneous endomyocardial biopsy

The objective of this study was to demonstrate the feasibility of isolating viable canine cardiac myocytes from percutaneous right ventricular endomyocardial biopsy specimens. Although histologic data can be obtained from percutaneous endomyocardial biopsies, this approach has not been used as a source of viable cells for evaluating pathological conditions. Study of isolated viable myocytes may provide insight into the electrical, biochemical, and physiologic functions of the heart. Using a standard 8F sheath, a 5F bioptome was introduced via the right femoral vein and advanced to the right ventricle, where 85 biopsies were obtained from 8 mongrel dogs. An average of six biopsy specimens were pooled for processing to provide adequate tissue substrate. This resulted in 14 groups of specimens which were then processed to isolate individual myocytes. Viable myocytes were striated, rod-shaped, and excluded trypan blue dye. Nonviable myocytes were rounded, had no cross-striations, and did stain with trypan blue. Partially-injured myocytes contracted spontaneously and had a region of loss of cross-striations. The average number of viable cells recovered per group of pooled specimens was 1.8 × 10⁴ (1.8 × 10³ cells/mg of tissue). The greatest yield of viable myocytes recovered was 8.0 × 10⁴, which represented a viability of 90% by trypan blue dye exclusion and morphological criteria. Percutaneous right ventricular endomyocardial biopsy is a novel method for obtaining viable cardiac myocytes. Its feasibility and utility in humans warrant further investigation. © 1996 Wiley-Liss, Inc.     

Muscle-nerve involvement in autosomal dominant progressive external ophthalmoplegia with hypogonadism

Sixteen members of a family with a history of autosomal dominant progressive external ophthalmoplegia (adPEO) with hypogonadism were examined. The muscular involvement commenced cranially and descended in relation to increasing disease duration. The neuromuscular signs were PEO, dysarthria, dysphonia, limb muscle weakness with wasting, absence of Achilles tendon reflexes, and distal vibration sensory loss. The electromyogram (EMG) was myopathic in facial and proximal limb muscles. Neurogenic involvement was suspected in a few tibial anterior muscles. Neurography showed signs of axonal neuropathy correlated to clinical signs. F-responses were reduced in number or absent in peroneal nerves, and did not correlate to clinical signs or disease duration. Muscle biopsies in advanced cases had structural abnormalities of mitochondria, ragged-red fibers, and focal cytochrome c oxidase deficiency. A combination of muscle-nerve involvement with PEO, Achilles tendon areflexia, distal vibration sensory impairment, myopathic EMG, and abnormally low sural nerve responses seems to be typical of this type of mitochondrial disorder. © 1996 John Wiley & Sons, Inc.     

Computerized tomography and magnetic resonance muscle imaging in Miyoshi's myopathy

We describe clinical, pathological, and muscle imaging findings in a patient with an early adult-onset progressive muscular weakness in association with atrophy beginning in the legs and involving both gastrocnemi in particular. Muscle biopsy findings showed a severe dystrophic process with no vacuoles, consistent with Miyoshi's myopathy. Computerized tomography and magnetic resonance imaging scans were used to provide an ongoing permanent record of the various stages of the disease. © 1996 John Wiley & Sons, Inc.     

Reduced brain stem excitability in mitochondrial myopathy: Evidence for early detection with blink reflex habituation studies

Blink reflex (BR) was studied in 17 patients with histochemically and genetically confirmed mitochondrial myopathy (MM). Fourteen patients had chronic progressive external ophthalmoplegia (CPEO) associated with a mild to moderate craniosomatic myopathy without any symptoms or signs of central nervous system (CNS) involvement, 2 myoclonic epilepsy with ragged red fibers syndrome, and 1 Kearns-Sayre syndrome. The mean latencies of the early (R1) and late (R2) responses were prolonged (P < 0.01 and P < 0.001, respectively), and the corresponding amplitudes decreased (P < 0.001). Increased habituation of the reflex was clearly observed in 10 out of 14 patients tested (71.4%), 9 of whom presented CPEO. These findings suggest that the brain stem reticular network is in a state of basal inhibition which is presumably due to a subclinical impairment of the cerebral cellular metabolism. Multimodal evoked potentials revealed abnormalities suggestive of CNS involvement in 7 out of 17 patients (41.2%), 4 of whom had CPEO. These observations document the validity of BR in detecting clinically silent brain stem impairment in patients with apparently pure MM and provide important clues for a further understanding of the underlying pathophysiology. © 1996 John Wiley & Sons, Inc.     

重叠综合征并发横纹肌溶解症一例

74岁女性患者,手足及口周部位皮肤变硬2个月余,伴乏力、酱油色尿1个月。血清肌酸激酶4 242 U/L,肌红蛋白1 124 ng/ml。诊断为重叠综合征并发横纹肌溶解症。经甲泼尼龙80 mg每日1次、甲氨蝶呤15 mg每周1次治疗,效果不理想,转入肾病内科行血液净化治疗。血清肌红蛋白恢复正常后,继续口服甲泼尼龙40 mg每日1次,定期复诊并缓慢减量。目前甲泼尼龙减量至16 mg/d,己持续治疗1年,血清肌酸激酶及肌红蛋白均在正常范围。     

慢性进行性眼外肌瘫痪型线粒体肌病(附3个家系报告)

目的 探讨家族性慢性进行性眼外肌瘫痪（CPEO）型线粒体肌病的临床、遗传和病理特点。方法 回顾性分析CPEO型线粒体肌病3个家系21例患者的临床表现、家系调查及5例肌活检病理学资料。结果 患者临床均表现为眼睑下垂和眼球运动障碍,伴或不伴有肌无力。1家系符合常染色体显性遗传规律,另2个家系符合母系遗传规律。病理改变：光镜下为破碎红纤维（RRFs）和细胞色素C氧化酶（COX）缺失纤维;电镜为肌膜下、肌原纤维间线粒体数量增多,嵴内可见电子致密颗粒或晶格样包涵体。结论 3个家系及其亲子代问临床与病理表现相似,提示不同遗传方式所致CPEO型线粒体肌病临床表现是相同的。     

成人发病的肌原纤维肌病的临床和病理学特征(附2例报告)

目的 探讨成人发病的肌原纤维肌病的临床和病理学特征.方法 回顾性分析2例成年发病的肌原纤维肌病患者的临床资料.结果 2例患者表现为近端或远近端肌肉无力,进行性加重.光镜下可见肌纤维内和肌膜下颗粒样或团块样物质沉积,免疫组化为结蛋白.电镜发现1例肌膜下及肌原纤维间存在大小不一的包涵体,另1例肌原纤维排列紊乱,Z线不规则样增粗.常见突变基因检测未见异常.结论 成人发病的肌原纤维肌病临床无特异性表现,其病理学特征为肌纤维内可见异常物质沉积,电镜发现肌原纤维间包涵体结构或Z线异常.