Protracted arthritis in a Japanese patient with familial Mediterranean fever.

The most common arthritic involvement in familial Mediterranean fever (FMF) is acute self-limiting monoarthritis which typically lasts for 72 h. Hip joint involvement is uncommon in FMF and can result either from a process specific to this disease or from a coexisting inflammatory joint disease. We describe a 37-year-old woman with FMF and right osteoarthritis secondary to congenital hip dislocation. Periodic fever with right coxalgia lasting for 6 months was treated using colchicine. Genetic analysis revealed homozygous mutation in the MEFV gene (L110P-E148Q/L110P-E148Q), confirming the FMF diagnosis. Although the clinical presentation and course of FMF arthritis are diverse, delineating these clinical patterns may help with early recognition and treatment to prevent destructive arthritis in FMF. Clinicians should consider the possibility of FMF development in unusual monoarthritis patients with recurrent febrile attacks.