Clinical characteristics of polymyositis-like hypothyroid myopathy in 10 cases

Abstract

Abstract Objectives To investigated the clinical characteristics and prognosis of hypothyroid myopathy Methods The clinical characteristics were analyzed in 10 patients diagnosed with polymyositis-like hypothyroid myopathy. Symptoms and indicators at baseline and after levothyroxine replacement therapy were compared. The correlations of muscle enzyme levels with thyroid function were analyzed. Results A total of 10 patients, including 3 males and 7 females, were enrolled. The average onset age was 46.1 ± 10.3 years and duration of disease was 2.1 ± 0.9 months. The first manifestation comprised proximal muscle weakness and myalgia or arthralgia. Liver dysfunction, hyperlipidemia, muscle enzyme increased, pericardial effusion, pleural effusion, and fatty liver was common. All patients were Hashimoto's thyroiditis and negative for myositis antibodies. Pathological muscle biopsies revealed myxoid degeneration and muscle atrophy. The proportion of patients who experienced proximal muscle weakness, myalgia, and/or arthralgia, ALT increased, AST increased, CHOL increased, TG increased, CK increased , CK-MB increased, LDH increased, fT3 decreased, and fT4 decreased were significantly lower after treatment(all P<0.05). Levels of ALT, AST, CHOL, CK, CK-MB, LDH, and TSH were significantly lower while levels of fT3 and fT4 were significantly higher after treatment(all P<0.05). CK, CK-MB, and LDH levels negatively correlated with fT3 and fT4, but positively correlated with TSH (all P<0.05). Conclusion Hypothyroid myopathy was more common in female. Most patients had liver dysfunction, hyperlipidemia and abnormal muscle enzyme levels, serous cavity effusion and fatty liver. Electromyography and muscle pathology had no specific alterations. The prognosis was well after levothyroxine replacement therapy.