Endocrine Abstracts

Multiple dose adjustments can sometimes be inefficient in reaching eumetabolic state in patients with hypothyroidism treated by levothyroxine sodium tablets. We report a case of 44-year-old female who has been on levothyroxine sodium tablet replacement therapy since 2004 without ever reaching eumetabolic state, presented as outpatient one year ago. As sellar MRI ruled out pituitary adenoma, investigation targeting malabsorption was initiated. Antibodies to gliadin and transglutaminase were in normal range. Absorption test with 300 mcg levothyroxine was positive in aspect of presence of selective levothyroxine malabsorption. Initial endoscopies revealed chronic atrophic gastritis without excluding possibility for tumor presence. Serum CgA level was 521 mcg/l. The final third endoscopy was successful in detecting the gastric submucosal change, confirmed by endoscopic ultrasound as submucosal lesion no larger than 12 mm located in the upper part of anterior gastric wall. Histological analysis of biopsy specimen confirmed lesion to be neuroendocrine tumor grade 1. Further imaging excluded its metastatic spreading, so the indication for surgical removal was established. Patient could not undergo surgery with TSH levels exceeding 100 mmU/l and free T4 lower than 5 pmol/l despite being on 300mcg of levothyroxine daily substitution regimen. Changing to a gel capsule formulation taken once a day at dose of 100 mcg lead to a rapid TSH decreasement and thyroid hormones normalization, so the patient was surgically treated as eumetabolic. On reviews thereafter she remained euthyroid, without complaints of previously reported fatigue and loss of appetite. This case suggests that gastric chronic inflammatory processes and neuroendocrine tumors as well may affect levothyroxine absorption where gelatine capsules appear to be effective treatment option.