Levothyroxine Malabsorption Induced by Diabetic Gastroparesis Exacerbated During Pregnancies: Effect of Intramuscular Levothyroxine Injections and Levothyroxine Soft Gel Capsules

ABSTRACT Objective: We report a case of severe hypothyroidism with levothyroxine (LT4) malabsorption induced by diabetic gastroparesis. This was exacerbated during the patient's 2 pregnancies. Management was improved by intramuscular (IM) LT4) injections and LT4 soft gel capsules. Methods: Case report with literature review. Results: A 23-year-old Hispanic female with type 1 diabetes (DM) and hypothyroidism developed diabetic gastroparesis with unpredictable responses to LT4. She had 2 pregnancies during which her oral LT4 was switched to weekly IM injections of LT4 that maintained her euthyroid state. An LT4 absorption test with 1,000 mcg LT4 revealed reduced LT4 absorption. A gastric emptying scan showed delayed emptying, and endoscopy demonstrated a large amount of residual food in the patient's stomach after an overnight fast. Weekly IM injections of LT4 and LT4 soft gel capsules maintained her euthyroid state after her last pregnancy with a follow-up longer than 1-year. A repeat LT4 absorption test with a 1,000-mcg LT4 soft gel capsule preparation demonstrated improved absorption compared to the initial LT4 absorption test. Conclusion: This may be the first patient described in the literature in whom diabetic gastroparesis was associated with impaired oral LT4 absorption and exacerbation during pregnancies. Our experience with this patient suggests that rational management of this problem may include IM LT4 injections or oral LT4 soft gel capsule administration. Abbreviations: CHF congestive heart failure DM diabetes mellitus IM intramuscular LT4 levothyroxine T4 thyroxine TFTs thyroid function tests TSH thyroid-stimulating hormone