Accepted on 5/9/01

The authors describe a case of pericardial effusion ac-companied by cardiac tamponade caused by primary hy-pothyroidism. Diagnosis was made by exclusion, because other causes of cardiac tamponade are more frequent. Emergency treatment of cardiac tamponade is pericardiocentesis (with possible pericardial window), and, after stabilization, performance of hormonal reposition therapy with L-thyroxin. Hypothyroidism, a disease with a multisystemic cha-racter that may present clinically in various forms, one being unusual pericardial effusion, is a cardiovascular complication that, according to the literature, is associated with hypothyroidism in 30 % to 80 % of cases 1,2. However, the occurrence of hypothyroidism and pericardial tampo-nade is a rare event. Pericardial effusion has a high concen-tration of protein and, like other serous effusions of hypo-thyroidism, its pathogenesis is not fully understood 3. The slow accumulation of liquid observed in the pericardial space is due to the frequent rarity of hemodynamic premoni-tory signs, even in the presence of large effusions. In this article, we report a the case of a patient who presented with pericardial effusion evolving rapidly to cardiac tamponade, the cause being primary hypothyroidism. Case Report A female patient, 47 years of age, was admitted to the service of the Medical Clinic of the Clinics Hospital of the Federal University of Paraná. She complained about short-ness of breath, weakness, and edema, with dyspnea after li-ght and heavy exertion starting 2 years earlier. The patient also reported asthenia and lower limb, facial, and abdomina