Hypothyroidism presenting as cardiac tamponade in Down syndrome.

Down syndrome is the commonest chromosomal anomaly. It is often associated with hypothyroidism, which may rarely present with cardiac tamponade as the earliest manifestation and prompt treatment with L-thyroxine is life saving. A six-month-old female child diagnosed as a case of Down syndrome presented with shortness of breathing for last 1 1/2 months. Facial dysmorphism, characteristic of Down syndrome was present. Echocardiography revealed large pericardial effusion and right ventricular diagnostic collapse. A case of Down syndrome with hypothyroidism and cardiac tamponade was kept in mind. She was treated with L-thyroxine and clinical status improved.