Case Reports
Tuesday, October 15, 2024
08:30 AM–10:00 AM
Abstract
Introduction:
Refractory hypothyroidism requires higher doses of levothyroxine than what is estimated by body weight with detailed investigation into potential causes. The objective of this report is to describe treatment of a patient with refractory hypothyroidism without a definitively known cause and its effect on thyroid level outcomes.
Case:
A 73-year-old male known to a family medicine practice was transferred to the emergency department from clinic and subsequently admitted for chief complaint of bilateral lower extremity edema. The patient’s NT-proBNP level was 40 pg/mL (0-375 pg/mL), thyroid-stimulating hormone (TSH) level was 225.5 µIU/mL (0.45-4.5 µIU/mL) and free T4 level was <0.10 ng/dL (0.82-1.77 ng/dL). He reports adherence to 300 µg levothyroxine by mouth daily. With consultation of an endocrinologist, the patient was treated with intravenous therapy (200 µg levothyroxine, 10 µg liothyronine, and 50 mg hydrocortisone). The patient continued 50 µg levothyroxine intravenously for six days and was discharged. Levels were repeated one month after discharge with continuation of home levothyroxine (300 µg by mouth once daily), TSH (0.15 mIU/mL) and free T4 (1.9 ng/dL). Repeat free T4 level was 1.9 ng/dL at six-month follow-up.
Discussion:
The patient’s physical exam and imaging was normal. His TSH had peaked at 321 µIU/mL during his care. Adherence has been verified multiple times through the patient and external sources. He does not have major disease states known to contribute to refractory hypothyroidism (ie., celiac disease). Little is known on how intravenous levothyroxine will affect levels over time. In this patient case, oral therapy was not controlling the patient’s hypothyroidism despite proper administration technique and increased doses. Intravenous therapy reduced the patient’s TSH and raised the free-T4 level, which has been maintained for the last six months.
Conclusion:
This case demonstrates the ongoing and acute difficulty in treating patients with refractory hypothyroidism, especially without a definitive cause.
Presenting Author
Thaddeus McGiness PharmDAuthors
Nathaniel Jordan DO
University of Tennessee Graduate School of Medicine - The Department of Family Medicine
Davis Mills DO, MBA
University of Tennessee Graduate School of Medicine - Department of Family Medicine
Kyle Osborn MD
University of Tennessee Medical Center
Kaitlyn Phillips PharmD
University of Tennessee Medical Center