Endocrine Abstracts

JOINT3409

Introduction: Myxedema coma (MC) is a rare but severe endocrine emergency caused by a significant depletion of thyroid hormones, which can be triggered by various factors, including infections (1,2). Early diagnosis and prompt management are crucial for improving prognosis and reducing mortality (3). We report a case of MC precipitated by a severe urinary tract infection.

Case Report: A 78-year-old female with hypertension and chronic kidney failure (CKD) was admitted for septic shock of urinary origin. Upon admission, she presented with coma, hypothermia, bradycardia, hypoventilation, and generalized myxedema. The electrocardiogram showed right bundle branch block with diffuse low voltage. Laboratory tests revealed severe hypothyroidism (TSH > 200 mU/l, FT4 < 0.42 pmol/l, FT3 1.4 pg/ml), cortisol level of 155 ng/ml, and acute decompensation of CKD. Transthoracic echocardiography showed a mildly hypertrophied left ventricle with good kinetics. Management included continuous cardiorespiratory, hemodynamic, and thermal monitoring, along with antibiotic therapy, urgent hemodialysis, and thyroid hormone replacement with L-thyroxine (LT4) via nasogastric tube, starting with a loading dose followed by maintenance. Hydrocortisone hemisuccinate was also administered. The patient initially showed improvement in heart rate but died 2 days later due to multivisceral failure.

Discussion & Conclusion: MC is an acute decompensation of prolonged hypothyroidism, potentially fatal, characterized by cognitive impairment, hypothermia, bradycardia, hypoglycemia, and renal and respiratory insufficiency (1,4). It can be triggered by various factors such as cold exposure, infections, trauma, or anesthesia (1). Management requires continuous monitoring of vital signs and urgent administration of L-T4 (200 to 400 mg IV). Hydrocortisone is also administered to prevent adrenal crisis (1). T4-T3 combination therapy may be considered, as the conversion of FT4 to FT3 can be impaired in severely decompensated patients or those on steroid therapy, although this approach remains controversial (5).

References: 1. Buoso, C., et al. (2024). Myxedema coma secondary to levothyroxine malabsorption in a patient previously submitted to bariatric surgery. Arch. Endocrinol. Metab., 68(1), 1-5. https://doi.org/10.20945/2359-4292-2023-0095. 2. Williams, C. (2023). A delayed diagnosis of myxedema coma. Cureus, 15(1), e33370. https://doi. org/10.7759/cureus.33370. 3. Sun, J., et al. (2023). Severe hypoxemia after extubation secondary to myxedema coma: A case report. Journal of International Medical Research, 51(9), 1-8. https://doi. org/10.1177/03000605231197947. 4. Chen, D. H., et al. (2023). Clinical features and outcomes of myxedema coma in patients hospitalized for hypothyroidism: Analysis of the United States National Inpatient Sample. Thyroid, 33(1), 1-10. https://doi.org/10.1089/thy.2023.0559. 5. Elshimy, G., et al. (2023). Myxedema. In StatPearls. StatPearls Publishing. https://www.ncbi.nlm.nih.gov/books/NBK545193/.