Myositis in a patient with familial Mediterranean fever and spondyloarthritis successfully treated with anakinra.

Familial Mediterranean fever is an autosomal-recessive autoinflammatory disorder more commonly observed in Mediterranean populations and characterized by recurrent episodes of fever, serositis, myalgia and arthritis. There is rarely any association with spondyloarthritis. The most important long-term complication is progressive systemic type AA amyloidosis. Treatment with colchicine is effective in reducing the frequency of attacks and prevents the development of amyloidosis. However, 5% of cases are considered resistant to colchicine. We here describe the case of a 39-year-old man, with a history of arthritis, arthralgias, and sacroiliitis in the course of a familial Mediterranean fever. He is homozygous for the M694I mutation in the MEFV gene. He subsequently developed myositis of the right quadriceps muscle confirmed by magnetic resonance imaging, electromyography and histology. He had frequent and severe arthralgias, despite colchicine, then etanercept and adalimumab, impairing his quality of life. The patient was successfully treated with the IL-1 receptor antagonist anakinra with a dramatic improvement of muscular and articular symptoms. To our knowledge, our patient is the first patient with coexisting FMF, spondyloarthritis and myositis responding to anakinra treatment. Moreover this is the second case in the literature of myositis associated with familial Mediterranean fever.