Eosinophilic pericarditis: a rare complication of idiopathic hypereosinophilic syndrome in a child.

We describe an 18-month-old child with idiopathic hypereosinophilic syndrome (IHES) who presented with fever, and cervical lymphadenopathy. Chest X-ray showed marked cardiomegaly, and echocardiogram revealed large pericardial effusion. Other causes of pericarditis were excluded. Despite the initiation of steroid therapy, signs of impending cardiac tamponade developed. Pericardiocentesis yielded bloody fluid with a white blood count of 14,800/mm3, of which 23% were eosinophils. The child recovered after pericardial drainage and prolonged systemic steroid therapy. Eosinophilic pericarditis is a rare but potentially dangerous complication of IHES.