Small pericardial effusion (PE) is not an infrequent manifestation in primary hypothyroidism. But massive PE with or without cardiac tamponade is rare and often associated with severe form of the disease. Here we report an eight-year-old boy who was admitted with massive PE that required repeated pericardiocentesis. Detailed examinations failed to identify the etiology initially. Five months later, child was readmitted with massive PE with impending cardiac tamponade. Primary hypothyroidism was diagnosed based on the clinical and laboratory finding and was thought to be the underlying etiology of previously encountered undiagnosed massive PE. Beside pericardiocentesis, child was treated with thyroid hormone replacement. Condition gradually improved without further recurrence of PE till date. Therefore, irrespective of the presence of clinical signs, primary hypothyroidism should be suspected in every patient presenting with massive PE to prevent recurrence as well as its serious complications like cardiac tamponade.
Key words: Pericardial effusion, Primary hypothyroidism, Cardiac tamponade, Levo-thyroxine.