Myxoedematous tamponade as initial presentation of Hashimoto's thyroiditis.

Cardiac tamponade as the initial presentation of hypothyroidism is extremely rare. We report the case of a 48-year-old man admitted for acute respiratory distress, with cardiac ultrasound showing compressive pericardial effusion. Percutaneous pericardiocentesis was performed leading to a rapid clinical improvement. Laboratory tests confirmed severe hypothyroidism related to Hashimoto's disease. Despite hormone replacement therapy, pericardial effusion recurred after 3 weeks, requiring surgical drainage. Pericardial histology highlighted slight chronic fibrous pericarditis. The cardiac ultrasound scan performed 4 months later showed a well-tolerated chronic pericardial effusion. In conclusion, hypothyroidism should be suspected in case of cardiac tamponade especially in the absence of tachycardia, or in winter when myxoedema is prone to decompensation. Prognosis is generally good under hormone replacement therapy but ultrasound monitoring should be carried out at least until euthyroidism is achieved.