The clinical and muscular pathological features of statin-induced myopathy

To explore clinical and muscular pathological features of statin-induced myopathy.Nine patients were enrolled in this study, who were diagnosed as statin-induced myopathy by muscle biopsy in Peking University First Hospital from April, 2012 to October, 2014. The clinical data and pathological findings were analyzed.The exposure time to statins varied from 4 days to 4 years in the total of 9 patients, 6 males and 3 females, with the average age of 63 ± 6 (55 to 74) years old. Three patients suffered from myalgia and 6 patients complained of weakness mainly at the proximal limbs, while no symptoms occured in 3 patients. Serum creatine kinase (CK) increased in all patients with the maximum value varied from 468 to 8 000 U/L. Serum myositis antibodies were tested in 7 patients and all were negative. Electromyogram was performed in six patients with myogenic damage found in 2 patients. MRI of bilateral thigh muscle was carried out in six patients with muscle edema and mild fatty infiltration found in 2 patients. All patients underwent skeletal muscle biopsy with histochemical and immunohistochemical staining. The main muscular pathological features were muscle fiber atrophy, necrosis, regeneration and increased lipid droplets. Ragged blue fiber, cytochrome C oxidase-negative muscle fibers and decreased NADH activity were observed in some patients. MHC-I expressed in the sarcolemma of muscle fibers at various levels. Mild C5b-9 staining was found in the endomysium, capillary and cytoplasm. Symptoms and the level of CK were improved in 7 patients after discontinuing statins or changing to another statin, while the immunosuppressive therapy were used in 2 patients and shown to be effective.Statin induced myopathy is self-limiting in most patients, with improvement after discontinuation of statins. Few patients with autoimmune necrotic myopathy need immunosuppressive therapy.PubMed中文核心期刊要目总览(PKU)中国科技核心期刊(ISTIC)8716-205