Abstract 16717: Managing Myxedema Coma: A Challenging Case of Cardiogenic Shock Culminating in Orthotopic Heart Transplantation

Background: Myxedema coma (MC) is a rare manifestation of severe hypothyroidism often seen in elderly female patients. While the sequelae of MC can lead to multi-organ involvement and eventual failure, irreversible Heart Failure (HF) is rarely seen. This case culminated in orthotopic heart transplant (OHT) for definitive treatment.

Case Presentation: A 23-year-old male presented with worsening RUQ abdominal pain for 2 weeks. In the ED, he had PEA arrest and with ROSC, he was admitted to the CCU for presumed cardiogenic shock, with labs remarkable for lactate 7.5 mmol/L, pro-BNP 6104 pg/mL, and markedly elevated serum creatinine and LFTs. The patient exhibited HF symptoms for 9 months before admission, manifesting as worsening LE edema, fatigue, and weight gain. He was also noted to have untreated hypothyroidism with repeat TSH of 857 μIU/mL on admission, indicating MC as a potential trigger for worsening HF. TTE revealed severe biventricular dysfunction with global hypokinesis and LVEF of 10-15%. Inotropic support was initiated with dobutamine, with RHC showing CVP 11 mmHg, RV 23/11 mmHg, PA 32/22 mmHg, PCWP 25 mmHg, and CI 2.3 LPM/m ² . Subsequent deterioration in CI and MVO2 necessitated IABP placement and vasopressor support, and later rescue VA-ECMO with atrial septostomy, aiming for OHT. Endocrine evaluation confirmed primary hypothyroidism, and the patient received high-dose levothyroxine, T3, and stress-dosed steroids. While there have been instances where cardiac consequences of myxedema HF were reversed by thyroid administration, his significantly dilated left ventricular internal dimension at end diastole, as well as complications of ECMO (bleeding) expedited his transplant evaluation. OHT was successfully performed on hospital day 14. Continuous improvement in thyroid function studies was observed throughout the treatment course with levothyroxine therapy.

Discussion: Worsening HF in the setting of MC, particularly in a male patient, is an uncommon presentation that requires prompt action. This patient required mechanical support as an eventual bridge to OHT with simultaneous treatment for hypothyroidism, illustrating the complexity of the case and the interventions necessary for a positive outcome in an uncommon clinical scenario.