核黄素反应性脂质沉积性肌病的临床和病理特征

Clinical and pathological characteristics of riboflavin-reactive lipid storage myopathy

目的探讨核黄素反应性脂质沉积性肌病的临床和病理特征。方法回顾性分析4例核黄素反应性脂质沉积性肌病患者的临床资料。结果本组4例患者表现为亚急性起病的四肢近端和躯干肌无力,不能耐受疲劳,3例患者有颈肌和脊旁肌萎缩、无力,2例有明显的咀嚼肌无力。2例肌电图示肌源性损害,1例示双侧胫神经传导速度轻度减慢。肌肉活检发现肌纤维内大量脂肪沉积,未见肌纤维坏死和再生,改良Gomori三色染色、琥珀酸脱氢酶和细胞色素C氧化酶染色以及电镜观察未发现有线粒体酶活性缺失,以及线粒体结构和数量的异常改变。应用维生素B2单药治疗后2例明显好转,2例痊愈。2例患者分别在治愈后1年、5年复发,重新给予维生素B2治疗仍然有效。结论本病多以颈肌、脊旁肌和咀嚼肌受累,病理特征为肌肉脂肪沉积,无线粒体异常改变。维生素B2单一治疗对本病有显著疗效,此亦可与其他肌病鉴别。

Objective To investigate the clinical and pathological features of riboflavin-reactive lipid storage myopathy. Methods Clinical material of 4 patients with riboflavin-reactive lipid storage myopathy were analyzed retrospectively. Results All the patients were subacute onset and presented proximal and axial muscle weakness accompanied by intolerance to excise. Amyotrophy and weakness involved in neck and paraspinal muscle were found in 3 cases, and chewing muscle weakness in 2 cases. Electromyogram showed myogenic changes in 2 cases and reduced conductive velocity of tihial nerves in I case. Muscle Biopsy study showed markedly increased lipid droplets in muscle fibers. The ragged red fibers, succinate dehydrogenase strongly reactive vessels and COX deficiency fibers which supported mitochondrial myopathy were not detected. Electromicroscope observation revealed that the structure and quantity of mitochondria were normal. All the patients had a dramatic response to riboflavin treatment. Two cases were cured and the other two were improved significantly. Two cases relapsed I year and 5 years later, respectively, and. riboflavin was still effective for them. Conclusions Riboflavin-reactive lipid storage myopathy is a myopathy characterized by preferential involvement of neek, paraspinal and chewing muscles. The distinct pathological features are lipid accumulation in muscle fibers without any abnormalities of mitochondrial structure and quantity. Riboflavin alone is effective for this myopathy and this is distinguished from other myopathies.