MON-444 Hematological Manifestations of Hypothyroidism

Abstract Disclosure: F. Spall: None. A. Spall: None. K. Alexander: None. S. Syed: None. INTRODUCTION: Hypothyroidism is closely linked to anemia, as thyroid hormones are essential in regulating erythropoiesis. The mechanisms behind this include decreased erythropoietin production, disrupted iron metabolism, and impaired bone marrow function, all of which contribute to anemia in hypothyroid patients. Recognizing this connection is crucial for accurately diagnosing and managing anemia in individuals with thyroid dysfunction. CASE REPORT: A 35-year-old Spanish male with a history of post-surgical hypothyroidism following a thyroidectomy at age 7, and ongoing levothyroxine supplementation, presented with multiple episodes of hematemesis. On arrival, he exhibited hypothermia and hypotension. Although he had been on levothyroxine, he had missed his medication for the past month due to insurance issues. Initial vital signs showed a temperature of 94.8°F, blood pressure of 90/46 mmHg, heart rate of 52 bpm, and oxygen saturation of 95% on room air. Lab results revealed a hemoglobin of 5.1 g/dL, consistent with normocytic anemia, along with a platelet count of 172 and normal coagulation parameters (PT 14.7, PTT 20.3, fibrinogen 214). TFTs showed a markedly elevated TSH of 309.9 µU/mL and a low free T4 of 0.29 ng/dL. On examination, the patient appeared lethargic and was admitted to the ICU for management of acute blood loss anemia and hemorrhagic shock secondary to severe hypothyroidism, requiring vasopressor support. Treatment included packed red blood cells (PRBCs), hydrocortisone, levothyroxine supplementation, and vasopressors. Hydrocortisone was discontinued after normal morning cortisol levels excluded adrenal insufficiency. Myxedema coma was deemed unlikely due to preserved mental status, no edema, and resolution of hypothermia. Levothyroxine was administered, resulting in a gradual improvement in TSH levels. Testing for acquired von Willebrand factor (vWF) disease, which can be associated with hypothyroidism, returned negative results. Although the initial vWF test was negative, it’s important to note that lab results may take time to appear. The patient’s anemia was likely due to impaired thyroid hormone production affecting erythropoiesis and red blood cell production. CONCLUSIONS: This case highlights the substantial impact of severe hypothyroidism on anemia and emphasizes the importance of considering thyroid dysfunction in the differential diagnosis of treatment-resistant anemia. Early diagnosis and proper levothyroxine supplementation are essential for effective management. Presentation: Monday, July 14, 2025