Familial Mediterranean fever and spondyloarthritis: Case report, diagnostic and therapeutic difficulties

Introduction: Musculoskeletal involvement is the second common manifestation in Familial Mediterranean Fever patients (FMF). Sacroiliitis and spondyloarthritis (SpA) are a rare condition in this disease. Case report: We present a 52-year-old woman with FMF and SpA and discuss particularities of this link. The patient had FMF since the age of 20 with intermittent inflammatory low back pain since the age of 28 and polyarthralgia of knees, left wrist and shoulders for a year. On examination there was limited extension of the left wrist and range of motion of the spine; pelvic examination and sacroiliac joints were normal. Molecular genetic analysis revealed a homozygous mutation of M649V. Laboratory investigations revealed an elevated C-reactive protein and erythrocyte sedimentation rate (31 mg/dl and 69 mm/1sth respectively). Further investigation showed a negative human leukocyte antigen-B27, antinuclear antibodies, anti-citrullinated peptides antibodies and rheumatoid factor. Pelvic and spine x-rays showed small areas of bilateral increased density and irregularity over the sacroiliac joints indicating grade 3 bilateral sacroiliitis and syndesmophytes. Magnetic resonance imaging of the spine revealed dorsal spondylitis and syndesmophytes. The diagnosis of SpA was retained according to Amor’s criteria. The patient was treated initially with non-steroidal anti-inflammatory drugs, physiotherapy and sulphasalazine which were ineffective after 3 months. The patient then received anti-tumor necrosis factor-α with good response. Conclusion: Spndyloarthritis should be considered in FMF patients with associated sacroiliitis especially when there are leading symptoms and/or imaging abnormalities in the spine. Awareness of this co-existence is important among rheumatologsits for a timely and precise management plan. Keywords: Familial Mediterranean fever, Spondyloarthritis, Sacroiliitis, Anti-TNF-