Case Presentation: Pericardial effusion is relatively common in patients with uncontrolled hypothyroidism, but rarely, it progresses to cardiac tamponade. We describe a case of myxedema coma presenting with cardiac tamponade.   Discussion: A 63-year-old African American morbidly obese lady with history of hypothyroidism presented with worsening dyspnea and unresponsiveness. Family reported that she is non-compliant [...]