Some case report suggested that increased need for thyroxine may occur in overt celiac disease (CD). However, overt CD (with typical gastrointestinal symptoms) only represents 10 to 20% of cases of CD, being the majority represented by the atypical CD and other occult forms, in which extra intestinal symptoms prevail. Few data on the need for oral T4 in patients with occult CD are available. In this study we analyzed the replacement T4 dose in 68 hypothyroid patients with isolated Hashimotos thyroiditis (HT) and in 35 patients bearing both HT and atypical occult CD. We have evaluated the ability of the same dose of T4 to reach target TSH in 21/35 patients before and after gluten free diet (GFD). In the remaining 14/35 CD patients, noncompliant with GFD, we have analyzed replacement T4 dose and compared with the one observed in the 68 patients with hypothyroid HT without CD. In patients with isolated HT, the desired serum TSH (median=1.02 mU/l) was reached in all patients after 5±2 months of treatment at a median T4 dose of 1.31 μg/kg per day. After similar period and dose of T4, higher levels of TSH (median=4.20 mU/l) have been observed in patients with HT and CD. In 21 CD patients, target TSH (median TSH=1.25 mU/l) has been attained after 11±3 months of GFD without increasing T4 dose (1.32 μg/kg per day). In the remaining 14 patients, noncompliant with GFD, target TSH has been achieved but at higher T4 dose (median=1.96 μg/kg per day;+49%; P=0.0002) than in hypothyroid patients without CD. Our data shows that absorption of thyroxine is impaired even in occult celiac disease and this effect is reversed by GFD or overcome by increasing T4 dose. Malabsorption of T4 may be a tool to unveil the presence of occult forms of celiac disease in T4 treated patients.
Declaration of interest: The authors declare that there is no conflict of interest that could be perceived as prejudicing the impartiality of the research project.
Funding: This work was supported, however funding details unavailable.
05 - 09 May 2012
European Society of Endocrinology