Graves’ Thyrotoxicosis and Fulminant Myopericarditis: A Clinical Dilemma!

Abstract

\n Myocarditis is a rare presentation of Graves’ disease, fulminant myocarditis is even rarer. We report a woman with Graves’ disease with fulminant myopericarditis as the presenting clinical feature. A 23-year-old healthy woman presented with acute onset pleuritic chest pain, palpitations, diaphoresis, heat intolerance, and dyspnea. There was no history of fever, upper respiratory tract infection, diarrhea, or weight loss. Physical exam revealed sinus tachycardia and palpable non-tender thyroid. Blood work was pertinent for TSH <0.01uIU/ml(0.3-4.5), free T4 2.8ng/dl(0.6-1.5), free T3 > 32.6pg/ml (2.4-4.2) and positive TSI (thyroid-stimulating immunoglobulin) 12.4 IU/L (<0.54). She had a diffusely enlarged vascular thyroid on ultrasound, all findings consistent with hyperthyroidism due to Graves’ disease. Electrocardiogram showed sinus tachycardia with diffuse PR depression and ST-segment elevation, troponin was 0.85 which increased to 17.5 within 12 hours, an echocardiogram showed normal ejection fraction (EF) with mild pulmonary hypertension but no pericardial effusion. She improved symptomatically with beta-blockers, methimazole, and colchicine but unfortunately had a witnessed ventricular fibrillation cardiac arrest in the next 12 hours with return to spontaneous circulation achieved after 90 minutes of bystander cardiopulmonary resuscitation. Coronary angiogram revealed normal coronaries with post-cardiac arrest EF of 5%. She subsequently developed acute respiratory distress syndrome secondary to massive pulmonary hemorrhage requiring extracorporeal mechanical support for worsening cardiogenic shock, succumbing to her illness a few hours later. Graves’ disease affects 0.5% of the population and causes hyperthyroidism in 50-80% of cases. Thyrotoxicosis may be associated with supraventricular arrhythmias and cardiomyopathy due to long-standing untreated hyperdynamic heart failure, but myopericarditis is an unusual presentation of Graves’ thyrotoxicosis with fulminant myopericarditis being even rarer. Fulminant myocarditis can present with ventricular tachyarrhythmias and can rapidly deteriorate into shock which may be difficult to distinguish from other causes of cardiogenic shock such as acute coronary syndromes or stress-induced cardiomyopathy. Myopericarditis associated with Graves’ is thought to be due to autoimmunity against functional TSH receptors identified in human cardiomyocytes. Fulminant myocarditis is a common cause of sudden cardiac death in young healthy adults, which is also the same population that gets Graves’ disease. It is critical to recognize the unusual presenting features of Graves’ disease such as fulminant myopericarditis, as timely aggressive intervention can reduce the risk of sudden cardiac death.