SUN-LB094 Massive Pericardial Effusion as an Initial Presentation of Hashimoto's Thyroiditis

Background: Pericardial effusion is a known complication of hypothyroidism and usually correlates with the severity and duration of the disease. However, massive pericardial effusion as the primary presenting manifestation of Hashimoto’s thyroiditis is extremely rare. Case: We present a 44-year-old female with a past history of diabetes mellitus who presented to the hospital with complaints of chest pain described as intermittent, sharp, non-radiating, 10/10 intensity ongoing for six days. On physical examination, she appeared lethargic with slow speech, cool dry puffy skin and muffled heart sounds on auscultation. EKG showed sinus rhythm and no significant ST-T wave changes and troponins trended negative. Initial lab-work was significant for a very high TSH of 86.4 (0.35-5.5 uIU/ml) and a low free T4 of 0.54 (0.61-1.12 ng/dl) with a normal free T3 and total T4. CBC, ESR and CRP were within normal limits. The patient did not endorse noticing any of the classical symptoms of hypothyroidism prior to this admission. Chest X-ray and Chest CT were concerning for a large pericardial effusion. Bedside echocardiogram revealed an ejection fraction of 30% and a massive pericardial effusion. No pericardial calcification or thickening was noted. Due to concern for tamponade physiology on echocardiogram, emergent pericardiocentesis was performed and 720 ml of straw-colored fluid was removed. Cardiac catheterization did not show any evidence of coronary artery disease and repeat echo showed trivial pericardial effusion with improvement in ejection fraction to 40-45%. The fluid analysis did not show evidence of mesothelial cells and cultures were negative. Serological markers for viral diseases (Coxsackie virus, EBV, Adenovirus), as well as immunological markers for rheumatoid arthritis (rheumatoid factor) and lupus (double-stranded DNA) were negative. Serum thyroid peroxidase (TPO) antibody was strongly positive: 877 IU/ml (<9IU/ml). Ruling out other common etiologies, pericardial effusion was attributed to severe hypothyroidism. The patient was treated with IV levothyroxine and IV hydrocortisone and her mental status improved over the course of her stay. Conclusion: Hypothyroidism should certainly be considered as a differential diagnosis in patients presenting with unexplained pericardial effusion. The mainstay of treatment for cases with mild to moderate effusions is thyroxine supplementation. Pericardiocentesis is only indicated in patients with massive effusion who are at risk of developing tamponade. Unless otherwise noted, all abstracts presented at ENDO are embargoed until the date and time of presentation. For oral presentations, the abstracts are embargoed until the session begins. Abstracts presented at a news conference are embargoed until the date and time of the news conference. The Endocrine Society reserves the right to lift the embargo on specific abstracts that are selected for promotion prior to or during ENDO.