Cause:Autosomal recessive MEFV gene on chromosome 16
Pathophys:Diffuse serositis in abdomen, chest, and joints; associated with a deficiency of a serosal protease, which is a C5a inhibitor (Nejm 1984;311:287, 325), and of interleukin-8
Eastern Mediterraneans, esp Sephardic Jews and Armenians; gene prevalence in some of these populations is as high as 1/14 to 1/21 (Nejm 1992;326:1509)
Sx:Onset in childhood or adolescence; positive family hx (30%)
Intermittent fever, abdominal pain lasting usually <1 day, pleurisy (40%), monoarticular joint pains without residua (esp in knees), acute scrotal attack (5%), myalgias × 6 wk
Si:Acute abdomen (peritonitis), splenomegaly, big kidneys
Death from amyloidosis before age 40 yr without rx
Amyloidosis (40%) with nephrosis, less in US than in Europe, colchicine rx helps (Nejm 1986;314:1001; Ann IM 1977;87:568); drug addiction, depression; infertility
r/o similar hyper-IgD syndrome, and TNF receptor-associated periodic syndrome
Lab:
PCR:Amplification refractory mutation system (ARMS) identifies 80% (Ann IM 1998;129:539)
Hem:ESR elevated, fibrinogen and other acute phase reactants increased
Joint fluid:Poor viscosity, polys >5000 up to 10 000
Xray: Periosteal new bone about femoral condyles (pathognomonic)
Rx: Colchicine 0.6 mg q1h up to 4-6 pills for acute attack; works in over half (Ann IM 1977;86:162), then 0.6-1 mg po qd-qid to prevent (Ann IM 1974;81:792; Nejm 1974;291:832, 934); 1-2 mg po qd × 15+ yr works and is safe even in pregnancy (Semin Arth Rheum 1991;20:241). Colchicine decreases poly migration rate so can’t clump so fast to exceed C5a inhibitor activity (Nejm 1984;311:287); prevents amyloid long term (Nejm 1986;314:1001)