Abdalla Mohammed S, Zhang Qishuo, Abdalla Monzer O, Abdel-Jalil Suhair S
Department of Internal Medicine, Ascension Saint Francis Hospital, Evanston, IL, USA.
Department of Rheumatology, Ascension Saint Francis Hospital, Evanston, IL, USA.
J Med Cases. 2023 Feb;14(2):64-70. doi: 10.14740/jmc4039. Epub 2023 Feb 25.
Statin-induced immune-mediated necrotizing myopathy (IMNM) is a subtype of IMNM linked to exposure to statins and is characterized by positive anti-hydroxymethylglutaryl (HMG) coenzyme A reductase (HMGCR) antibodies. Although rare, this entity has become increasingly recognized as a cause of proximal muscle weakness, especially with the widespread use of statin therapy. Unlike typical statin-associated muscle symptoms, IMNM myopathy often causes severe muscle injury, and muscle weakness persists or sometimes worsens following the withdrawal of statin therapy. Medical practitioners need to keep a high index of clinical suspicion for statin-induced IMNM in patients taking statins who present with muscle weakness. The disease can be debilitating, and treatment strategies are not well established despite the advances that have been made in the diagnosis. Here we present the clinical characteristics and disease course of two cases of statin-induced IMNM. Both patients presented with progressive proximal muscle weakness and myalgias while on long-term statin therapy without significant improvement in their symptoms following the withdrawal of statin therapy. IMNM was suspected, and both patients were found to have high titers of anti-HMG coenzyme A reductase antibodies and demonstrated microscopic features consistent with a diagnosis of IMNM on muscle biopsy. The patients experienced significant disability due to muscle weakness and required a protracted course of escalated immunosuppressive therapy. Although rare, IMNM should be suspected in patients taking statins who present with muscle weakness that fails to improve or worsens when statins were stopped. Early diagnosis and institution of immunosuppressive therapy are important to prevent the progression of the disease.
他汀类药物诱导的免疫介导性坏死性肌病（IMNM）是与他汀类药物暴露相关的IMNM亚型，其特征为抗羟甲基戊二酰（HMG）辅酶A还原酶（HMGCR）抗体阳性。尽管罕见，但随着他汀类药物治疗的广泛应用，该病症已越来越被认为是近端肌无力的一个病因。与典型的他汀类药物相关肌肉症状不同，IMNM肌病常导致严重的肌肉损伤，且在停用他汀类药物治疗后肌无力持续存在或有时加重。对于服用他汀类药物且出现肌无力的患者，医生需要保持高度的临床怀疑指数。该疾病可能使人衰弱，尽管在诊断方面取得了进展，但治疗策略仍未完全确立。在此，我们介绍两例他汀类药物诱导的IMNM的临床特征和病程。两名患者在长期接受他汀类药物治疗期间均出现进行性近端肌无力和肌痛，停用他汀类药物治疗后症状无明显改善。怀疑为IMNM，两名患者均检测出高滴度的抗HMG辅酶A还原酶抗体，肌肉活检显示的微观特征符合IMNM的诊断。患者因肌无力而出现严重残疾，需要长期进行强化免疫抑制治疗。尽管罕见，但对于服用他汀类药物且出现肌无力、在停用他汀类药物后症状未改善或加重的患者，应怀疑为IMNM。早期诊断和启动免疫抑制治疗对于预防疾病进展很重要。
