Rescue of Eosinophilic Cardiac Tamponade by Anakinra in a Pregnant Woman With Familial Mediterranean Fever

Familial Mediterranean fever (FMF) is an interleukin‐1 (IL‐1)‐driven autoinflammatory disease in which pericarditis, occasionally complicated by cardiac tamponade, is a recognized manifestation, whereas hypereosinophilia is not. We report a woman in her thirties with FMF (homozygous MEFV M694V mutation) receiving colchicine 2.5 mg/day, admitted in the third trimester of pregnancy for dyspnea, fever, and cough. She had blood hypereosinophilia (2.9 G/L), bilateral lung consolidation with bronchoalveolar lavage eosinophilia (46%) and myopericarditis. Cardiac tamponade required emergency pericardiocentesis and cesarean section, with favorable maternal and neonatal outcomes; pericardial fluid contained more than 90% eosinophils. Infectious, autoimmune, drug‐induced, and clonal causes were excluded. High‐dose corticosteroids only transiently reduced the eosinophil count, which rebounded, while C‐reactive protein remained elevated. Both parameters normalized after anakinra was started, allowing corticosteroid withdrawal, with sustained remission at 36 months. Whether hypereosinophilia was a manifestation of FMF or a coincidental association remains undetermined. IL‐1 blockade nonetheless controlled both the serositis and the eosinophilia, and may limit corticosteroid exposure.