P-68 A CHALLENGING CASE OF HYPOTHYROIDISM

Abstract Introduction Hypothyroidism is a common disease. L thyroxine once reached the stomach, undergoes disintegration and dissolution, and the active ingredient must reach the actual site of absorption. Disintegration is highly affected by the type of the formulation, the fasted or fed state, the gastric residence time, and the gastric motor function. The dissolution process consists of the release of solute molecules from the solid phase to the liquid one. Gastric juice pH. food, drugs and H pylori can affect L thyroxine absorption. Clinical Case IAA; A 54 y old female patient, known case of follicular thyroid carcinoma (FTC) since 2013, managed with total thyroidectomy, multiple radioactive iodine doses due to residual tissue. Post operative hypocalcemia that was resolved within a year. She was doing well on L- thyroxine suppressive dose of 200mcg/d. In 2018; she was operated for breast carcinoma, received chemotherapy and tamoxifen tablets. She was doing well on L thyroxine suppressive dose 250 mcg/d taken one hour before breakfast on an empty stomach, and was in complete remission regarding FTC. She lost to follow up for nearly one year. Her investigations: TSH= 39.7 mu/l, FT4= 6 (normal= 6.5-22 pmol/l), hemoglobin= 10.7 g/dl, calcium 8.7 mg/dl (normal= 8.4-10.5mg/dl not on calcium tab), celiac and H pylori serological screening were negative. TSH after 3 months =12.8 mu/l, She denied non compliance, Dose of L- thyroxine increased and gluten free diet was tried and did not work, dose increased to 400mcg/d. She was lost to follow up and came after one year,TSH =80 mu/l. L-thyroxine absorption test was performed; and L thyroxine mal-absorption was confirmed. She was advised to crush L-thyroxine 400 mcg/day and take it with water. TSH after two months was =13, free T4 =14 (normal=6.5-22 pmol/l). Gastroscopy showed pan moderate edematous gastritis and moderate erosive duodenitis. Duodenal biopsy showed chronic inflammation, negative celiac disease or malignancy. Conclusion Thyroid hormone is important for growth of intestinal mucosa. Selective L thyroxine malabsorption in the present case could be related to poor drug compliance and chronically uncontrolled thyroid status lead to intestinal edema and malabsorption. The other explanation was that gastritis caused inability of the stomach to properly dissolve tablet preparations to yield the active ingredient. The good response to crushed L thyroxine, which was a method of giving the drug to infants, suggested L thyroxine malabsorption problem started from the stomach.