Articular manifestations in Egyptian children with familial Mediterranean fever

Familial Mediterranean fever (FMF) is an autosomal recessive auto-inflammatory disease. Arthritis in early-onset FMF is a common finding. The aim of this study was to assess frequency of arthritis in 200 Egyptian children with FMF and also to detect its clinical characteristics, response to colchicine treatment, its effect on disease severity, and the most common MEFV gene mutations in patients with arthritis. We studied 200 children with FMF. We analyzed joint involvement in FMF attacks regarding its clinical characteristics, its effect on the disease severity, and response to colchicine treatment. We found arthritis in 20.5% of the studied population. Most of the children with arthritis had mono-articularjoint involvement during the FMF attack (73.1%), followed by oligo-articularjoint (22%). The knees and ankles were the most commonly affected joints. Arthritis was the presenting symptom in only 4%. We observed redness of the affected joints in 70.7%, and persistence of swelling after the attacks only in 17.1%. The majority of patients (85.4%) had a 75–100% decrease in the frequency of arthritic attacks after colchicine treatment. We did not find any joint disability in all studied patients, and arthritis was only present during attacks. The most frequent MEFV gene mutations in arthritic patients wereV726A and E148Q, each occurring in 28.6%. We observed an earlier age of disease onset and a more disease severity in patients with arthritis (p = 0.031 and p ≤ 0.001, respectively). We also observed that chest pain, erysipelas-like-erythema, and testicular affection were more observed in patients with arthritis (p values 0.001, 0.001, and 0.006, respectively). This study showed that around 20% of Egyptian children with FMF can develop arthritis during the attacks, which usually runs a benign course. The presence of arthritis can denote a more severe disease course.