Colchicine-induced myopathy in a teenager with familial Mediterranean fever.

Abstract

To report a case of colchicine-induced myopathy in a teenager with familial Mediterranean fever (FMF). A 15-year-old boy of Turkish origin, diagnosed as having FMF at the age of 14 years, was treated with colchicine 1.5 mg/d. He had experienced only 2 mild peritonitis attacks with fever within 1 year. The patient used the recommended dose regularly, and he described progressive proximal muscle weakness and generalized myalgias, which started 1 month before presentation. Physical examination showed proximal muscle weakness in his arms and legs. Laboratory tests revealed elevated serum creatine kinase, aspartate aminotransferase, alanine aminotransferase, and lactate dehydrogenase. All other laboratory values were within normal range. Electromyographic investigation revealed a myopathic pattern in proximal muscles without any neuropathic changes. A biopsy of the deltoid muscle showed vacuolar degeneration of striated muscle fibers with no inflammatory findings. Colchicine, the most important drug in treatment of FMF, can cause myopathy in patients with impaired renal and hepatic function. In our patient, an objective causality scale showed that therapeutic doses of colchicine for FMF were the definite cause of myopathy, even though his renal and hepatic function were normal. The treatment of FMF attacks in patients who cannot use colchicine is an important problem. There are insufficient data about the use of immunosuppressive agents in the treatment of FMF attacks; however, we now successfully control the attacks with colchicine 0.5 mg/d and azathioprine 2 mg/kg/d. Colchicine-induced myopathy should be excluded in patients with FMF who present with generalized muscle weakness. Clinicians should be aware that myopathy can occur in patients with FMF who have normal renal and hepatic function.