Incomplete attack and protracted sacroiliitis: an unusual manifestation of FMF in a child

Abstract

We describe an unusual presentation of a patient with familial Mediterranean fever (FMF) in whom the protracted sacroiliitis was the dominant clinical feature with incomplete abdominal attacks. An 11-year-old Turkish girl was referred for evaluation of recurrent abdominal and low back pain. Recurrent abdominal pain started while she was 6 years old without fever lasting for 1–2 days and localising at the right lower quadrant with full remission after the attack. She had a history of appendicectomy at the age of 7 years which was not productive. The complaints recurred every 1–2 months. As for her low back pain, complaints started when she was 2 years of age with exacerbation on exercise. Low back pain recurred every 2–3 months and persisted for more than a month. Throughout the period of 6–11 years of age, she had been prescribed nonsteroidal anti-inflammatory drugs (NSAID) which proved to be non-beneficial. She had no history of recurrent upper respiratory infection, psoriasis, chronic diarrhoea, oral aphthae or genital ulcers. There is no family history of periodic fever, FMF, spondyloarthropathy, rheumatoid arthritis, psoriasis or inflammatory bowel disease or Behcet’s disease. Physical examination revealed tenderness on pressure of the pelvis in the lateral position and no restriction on movement of the lumbar spine or on chest expansion. There was no abnormal ocular finding; neurological and other joint examinations were normal. Laboratory investigations revealed that HLA-B27 antigen, rheumatoid factor and antinuclear antibody were negative. During the attacks, C-reactive protein was 11.6 mg/dl and fibrinogen was 524 mg/dl while complete blood count, erythrocyte sedimentation rate, blood biochemistry and urinary analyses were normal. An anteriorposterior plain radiogram of the pelvis showed negative findings consistent with her complaints. Pelvic magnetic resonance imaging (MRI) revealed a chronic bilateral sacroiliitis grade 2 (Fig. 1). Molecular analysis showed a homozygous M694V mutation in the Mediterranean fever (MEFV) gene. For a period of 2 years under regular colchicine therapy, the patient experienced neither FMF attacks nor low back pain with no positive physical findings of sacroiliitis.