Case report: increased levothyroxine requirement in a patient with cryptic celiac-sprue disease

An increased requirement for levothyroxine may be due to poor patient compliance, pregnancy, low potency levothyroxine preparations, interfering drugs and small intestinal disease. Data on thyroid hormone absorption in celiac sprue disease is limited to a single study involving four patients without thyroid disease, in which malabsorption of a single dose of radiolabeled levothyroxine was noted in three of the four subjects. Increased levothyroxine requirements have not been reported in hypothyroid patients with celiac sprue. Furthermore, cryptic celiac sprue has never been described to cause levothyroxine malabsorption. We report such a patient in whom cryptic celiac sprue was an important cause of levothyroxine malabsorption with increased thyroid hormone requirement.