Mystery case: a 63-year-old man with progressive proximal pain and weakness.

A 63-year-old man with a history of type 2 diabetes presented with hip and shoulder pain in June 2010. He was on atorvastatin 80 mg daily and his creatine kinase (CK) was mildly elevated, so he was switched to simvastatin 20 mg daily. Three months later, he was referred to a rheumatologist. His CK was 142 U/L and his erythrocyte sedimentation rate (ESR) and C-reactive protein (CRP) were mildly elevated (28 mm/hour and 14 mg/L, respectively). He was diagnosed with polymyalgia rheumatica. He was started on a methylprednisolone taper starting at 16 mg going to 8 mg daily with mild, although transient, improvement. He remained on 8 mg daily methylprednisolone for several months. Eight months later, he began to notice progressive proximal leg weakness and difficulty climbing stairs. His serum CK was 1,600 U/L. He stopped the simvastatin and was started on gemfibrozil. An EMG was normal. His CK rose to the 3,000s IU/L 3 months later. Nine months later, 8-day methylprednisolone tapers starting at 16 mg daily were symptomatically ineffective, as was a prednisone 60 mg daily tapered over 2 weeks.