The etiology and treatment of refractory Hypothyroidism - management issues: A cross sectional observational study

Abstract

Introduction: Primary hypothyroidism is considered to be refractory to treatment when there is clinical or biochemical evidence of hypothyroidism (level of TSH above the target range, usually 5.5 mIU/L) even after 6 weeks of treatment with Levothyroxine at a dosage of 1.9 mcg/kg/day. This study intended to find out the common factors responsible for the refractory nature of the hypothyroidism. The study also highlights how simple correction measures would improve the outcomes. Materials and Methods: This is a prospective, Cross sectional and observational study conducted in the Department of Endocrinology, Sapthagiri Institute of Medical Sciences and Research center. The study population included 25 patients with treatment refractory hypothyroidism. The patients were identified after screening about 900 patients with primary hypothyroidism, between age group of 15-50 years and BMI of 19-25 kg/m2. Levothyroxine absorption test was performed when deemed necessary. Results: In 10 patients (40%) the reason for refractory nature of the hypothyroidism was found to be due to keeping the levothyroxine containers in the kitchen close to flame or above the refrigerator and due to disposing of the silica pack from the container. In 8 (32%) patients the reason was inappropriate timing of Levothyroxine with food and beverages or due to the usage of concomitant medications. 6 (24%) patients used generic Levothyroxine, which could be less effective. Remaining 1 patient (4%) were subjected to Levothyroxine absorption test, which suggested that malabsorption is the etiological factor. Conclusions: The most common reason for the refractory nature of the hypothyroidism was found to be due to improper storing conditions of the medication. The other reasons included switching over to the generic brands of levothyroxine, and not maintaining the adequate time gap between consumption of Levothyroxine and interfering medications like antacids. Malabsorption was found to be uncommon reason for refractory hypothyroidism.