Uruha Akinori
Department of Neurology, Tokyo Metropolitan Neurological Hospital.
Brain Nerve. 2024 May;76(5):646-654. doi: 10.11477/mf.1416202655.
Immune-mediated necrotizing myopathy (IMNM) is a form of autoimmune myositis characterized by the presence of necrotic and regenerating process as a major finding in the muscle. Anti-SRP and anti-HMGCR have been identified as IMNM-specific autoantibodies. Patients with this disease often present with severe muscle weakness and markedly elevated serum creatine kinase (CK) levels. Differentiation from muscular dystrophy is challenging in certain cases. When patients meet the condition "subacute onset", "hyperCKemia over 1000 IU/L", and "clinical diagnosis of muscular dystrophy lacking molecular diagnosis", the possibility of IMNM should be considered. Autoantibody measurement, including of anti-SRP and HMGCR antibodies, is recommended. Treatment with corticosteroid in combination with immunosuppressants, intravenous immunoglobulin, and rituximab can be performed.
免疫介导的坏死性肌病（IMNM）是一种自身免疫性肌炎，其特征是肌肉中存在坏死和再生过程，这是主要发现。抗信号识别颗粒（SRP）抗体和抗3-羟基-3-甲基戊二酰辅酶A还原酶（HMGCR）抗体已被确定为IMNM特异性自身抗体。该疾病患者常表现为严重肌无力和血清肌酸激酶（CK）水平显著升高。在某些情况下，与肌营养不良症进行鉴别具有挑战性。当患者符合“亚急性起病”、“CK超过1000 IU/L的高CK血症”以及“临床诊断为肌营养不良症但缺乏分子诊断”这些条件时，应考虑IMNM的可能性。建议进行自身抗体检测，包括抗SRP和HMGCR抗体检测。可采用皮质类固醇联合免疫抑制剂、静脉注射免疫球蛋白和利妥昔单抗进行治疗。
