9381 Hypothyroidism Unmasked: A Rare Culprit Of Cardiac Tamponade

Abstract Disclosure: N. Shaykh: None. A. Agrawal: None. N. Patel: None. F. Patel: None. V. Tripathi: None. O. Rai: None. P. Reddy: None. While pericardial disease may manifest in severe cases of hypothyroidism, occurrences of cardiac tamponade are uncommon. A 37-year-old female 19 weeks into her pregnancy with past medical history significant for Graves’ disease status post RAIU at age 15 and untreated hypothyroidism due to medication non-compliance required admission to the hospital for medical management of miscarriage. Labs were notable for TSH 61.6 MIU/L (0.270- 4.200 MIU/L) and thyroxine level 0.1 ng/dL (0.80 - 1.70 ng/dL) with a thyroid peroxidase antibody within normal range. Thyroid ultrasound was unremarkable. Clinically, the patient did not appear to be in myxedema coma and remained hemodynamically stable. Patient was started on levothyroxine 150 mcg daily with specific intake instructions as to not impede absorption. Her course was further complicated by new-onset chest pain with unremarkable ischemic workup. Transthoracic echocardiogram, however, showed a moderate pericardial effusion with right ventricular collapse suggestive of tamponade physiology likely related to her severe hypothyroid state. Patient was started on intravenous fluids and transferred to the cardiac ICU for monitoring. She underwent pericardiocentesis with 500 mL of serous fluid extraction. Fluid studies were not suggestive of infection or a rheumatologic cause. The decision was later made for a pericardial window due to fluid re-accumulation with drain in place for three days. Repeat thyroxine levels uptrended to 0.7 ng/dL, and serial echocardiograms showed pericardial effusion reduced in size with no hemodynamic compromise present. Patient was cleared for discharge with plans for repeat echocardiogram in two months and close outpatient follow-up. The presence of pericardial effusion in hypothyroidism seems to correlate with the severity of the condition. While research indicates a low occurrence rate of pericardial effusions in hypothyroidism, ranging from 3-6%, clinicians should maintain a heightened awareness based on the comprehensive clinical assessment, as cardiac tamponade poses a significant risk regardless of the size of the effusion. Management typically involves urgent pericardiocentesis and administration of thyroxine hormone replacement therapy. Patil VC, Patil HV, Agrawal V, Patil S. Cardiac tamponade in a patient with primary hypothyroidism. Indian J Endocrinol Metab. 2011 Jul;15(Suppl 2):S144-6. doi: 10.4103/2230-8210.83358. PMID: 21966654; PMCID: PMC3169864. Presentation: 6/1/2024