Polymyalgia rheumatica and type 2 diabetes mellitus complicated with electromyographic abnormalities that responded well to corticosteroid therapy.

A 62-year-old man who had a 14-year history of diabetes complained of low-grade fever, general malaise, pain of bilateral femurs and hip girdle, and was adniitted to our hospital. The diagnosis of polymyalgia rheumatica (PMR) was made from the clinical symptoms, elevated C-reactive protein and erythrocyte sedimentation rate. Electromyography revealed abnormalities that suggested diabetic peripheral neuropathy. However, the abnormalities were improved after starting treatment with corticosteroids (PSL). After stopping PSL, electric nerve conduction disturbance developed; therefore, it was suggested that peripheral nerve involvement due to PMR was improved by administration of PSL regardless of the existence of diabetic peripheral neuropathy.