6517 Cardiac Tamponade Secondary to Occult Primary Hypothyroidism

Abstract Disclosure: L. Javed: None. H. Al jumaili: None. A. Mahaldar: None. I. Goyal: None. N. Shakir: None. E. Punni: None. Introduction: The incidence of pericardial effusion in hypothyroidism seems to correlate with severity and duration of the condition and ranges from 3% to 37%. Cardiac tamponade resulting from hypothyroidism is exceptionally rare. We present a case of a patient presenting with this complication.Case Summary:A 38-year-old woman presented during a routine clinic visit with symptoms of fatigue and was found to have elevated liver functions enzymes with ALT 107 (N<48 U/L ) and AST 70 (N<47 U/L)Further evaluation through abdominal imaging revealed incidental finding of a partially imaged moderate pericardial effusion. A subsequent echocardiogram showed circumferential pericardial effusion with early tamponade physiology, necessitating immediate referral to the emergency room (ER) for further assessment and management.Upon admission to the ER, the patient reported progressive fatigue, increased sleep and menorrhagia over 8 months. There were no accompanying symptoms of weight gain or constipation. Family history was positive for thyroid disease in her grandmother. Initial vital signs on admission were Blood pressure: 119/86, Pulse: 55, Respiratory Rate: 13, Temp: 36.7 °C. Electrocardiogram showed sinus bradycardia. Laboratory findings were significant for: Hgb 8.7 (N>11.5), MCV 77.5 (N>80 fL), mildly elevated ALT 56, markedly elevated TSH 255 (N<5 IU/mL), low free T4 <0.1 (N ≥ 0.7 ng/dL), low free T3 <0.6 (N ≥2.0 pg/m), and elevated TPO 472 (N 35 IU/mL). Infectious and rheumatologic work-up were negative. Thyroid ultrasound showed heterogenous echogenicity consistent with thyroiditis.Patient underwent urgent pericardiocentesis draining 750 ml of clear yellowish pericardial fluid. Simultaneously, the patient was initiated on daily levothyroxine at a dose of 112 mcg.Stability in hemodynamics and repeat echocardiogram showcasing no pericardial effusion facilitated the patient’s discharge. Notable improvement with reduction in TSH from 260 to 20 was seen at the one-month follow-up in endocrinology clinic. Conclusion: Hypothyroidism should be considered in patients diagnosed with cardiac tamponade presenting with bradycardia, as in this case. It's been observed that hypothyroidism can affect LFTs which typically resolve with thyroid replacement. Treatment of cardiac tamponade depends on the patient's hemodynamic status. For early mildly affected cases of tamponade, a conservative approach involving close monitoring and limiting fluid intake may suffice, but drainage is often necessary. Since the pericardial effusion and tamponade stem from hypothyroidism, there's a high chance of effusion recurring after drainage. Hence, administering levothyroxine is essential, often leading to effusion resolution within 2-12 months without recurrence. Presentation: 6/3/2024