Ayesha Sobiya Mahnaz, Meena A K, Vangala Navatha, Rajasekhar Liza, Kaul Subhash, Borgahain Rupam, Uppin Megha S
Department of Pathology, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.
Department of Neurology, Nizam's Institute of Medical Sciences, Hyderabad, Telangana, India.
Ann Indian Acad Neurol. 2018 Jan-Mar;21(1):62-67. doi: 10.4103/aian.AIAN_389_17.
Idiopathic inflammatory myopathies (IIMs) are a group of chronic, autoimmune disorders which include a new entity, necrotizing autoimmune myopathy (NAM). NAM lacks inflammation and presents with markedly elevated creatinine phosphokinase (CPK) levels. It is associated with connective tissue diseases (CTDs), statin use, malignancies, and most cases are idiopathic.
The objectives of this study are to describe the clinicopathologic features in muscle biopsy-proven cases of NAM. To emphasize the role of laboratory parameters such as CPK levels and myositis profile in the diagnosis of NAM.
This is a retrospective study including 15 patients of NAM diagnosed on muscle biopsy over a period of 2 years. The slides of the biopsies were reviewed, and clinical data, electromyography findings, and CPK levels were obtained. Myositis profile was done.
Necrotizing myopathy accounted for 13.63% (15 cases) of total inflammatory myopathies (110 cases) in the study. These were grouped into CTD-associated NAM, statin-associated NAM, paraneoplastic NAM and idiopathic NAM which was the common type. All cases presented with progressive proximal muscle weakness and had markedly elevated CPK levels. Anti-3-hydroxy-3-methyl-glutaryl-coenzyme A reductase and antisignal recognition particle antibodies were seen to be positive in six patients. Muscle biopsies showed predominant fiber necrosis with significant fiber degeneration and regeneration in the absence of inflammation. All patients received immunotherapy with significant improvement was seen in six patients with two mortalities.
Necrotizing myopathy is a new addition to the spectrum of IIM. Clinicopathologic correlation is important for appropriate diagnosis. It is found to be refractory to corticosteroids monotherapy. The course of illness is not uniform, and in some patients, there can be rapid worsening with mortality.
特发性炎性肌病（IIM）是一组慢性自身免疫性疾病，其中包括一种新的疾病实体——坏死性自身免疫性肌病（NAM）。NAM缺乏炎症表现，肌酸磷酸激酶（CPK）水平显著升高。它与结缔组织病（CTD）、他汀类药物使用、恶性肿瘤相关，且大多数病例为特发性。
本研究的目的是描述经肌肉活检证实的NAM病例的临床病理特征。强调实验室参数如CPK水平和肌炎相关指标在NAM诊断中的作用。
这是一项回顾性研究，纳入了2年内经肌肉活检诊断为NAM的15例患者。对活检切片进行复查，并获取临床资料、肌电图结果和CPK水平。进行了肌炎相关指标检测。
在该研究中，坏死性肌病占全部炎性肌病（110例）的13.63%（15例）。这些病例分为CTD相关的NAM、他汀类药物相关的NAM、副肿瘤性NAM和特发性NAM（最常见类型）。所有病例均表现为进行性近端肌无力，CPK水平显著升高。6例患者抗3-羟基-3-甲基戊二酰辅酶A还原酶抗体和抗信号识别颗粒抗体呈阳性。肌肉活检显示主要为纤维坏死，伴有明显的纤维变性和再生，无炎症表现。所有患者均接受了免疫治疗，6例患者病情显著改善，2例死亡。
坏死性肌病是IIM谱中的新增疾病。临床病理相关性对于准确诊断很重要。发现其对糖皮质激素单药治疗无效。疾病进程不一致，部分患者病情可迅速恶化并导致死亡。
