A rare case of massive pericardial effusion secondary to hypothyroidism.

Massive pericardial effusions secondary to hypothyroidism are rarely seen in the emergency department (ED). The case of a patient presenting with a relatively asymptomatic massive pericardial effusion due to hypothyroidism is described. The patient had a history of laryngeal carcinoma post-total laryngectomy and adjuvant radiotherapy 12 years previous. Although underlying malignancy was in the differential diagnosis, hypothyroidism was diagnosed through a detailed history and physical examination, thereby avoiding the need for pericardiocentesis. Thyroid replacement alone is sufficient for resolution of these effusions, although it may take many months. Pericardiocentesis is indicated only if cardiac tamponade develops. This rare but significant condition should be considered, especially when it occurs after acute cold exposure.