Background: Hashimoto thyroiditis (HT) is characterized by autoimmune-mediated destruction of the thyroid gland. Ca metabolism disturbance due to hypoparathyroidism among HT patients remains to be clarified.
Objective: To clarify the relationship between HT and primary hypoparathyroidism.
Patients and Methods: Serum levels of Ca, albumin, and whole PTH (wPTH, ECLIA) were measured in 21 patients with HT (mean age 13.4 years) and 18 thyroid autoantibody negative patients with type 1 diabetes as a control group (mean 15.0 years). Pearson's correlation coefficient was calculated for wPTH and albumin-corrected Ca value.
Results: In HT patients, the mean wPTH and corrected Ca were 28.39 pg/mL and 8.68 mg/dL, respectively. In the control group, the averages of wPTH and corrected Ca were 27.85 pg/mL and 9.03 mg/dL, respectively. There was a correlation between the wPTH and Ca levels in the control group with a correlation coefficient of r = 0.497 (P <0.05), whereas no significant correlation was observed in patients with HT (P = 0.190). Even when excluding a patient with apparent hypocalcemia on treatment from the analysis, wPTH levels did not correlate with corrected Ca (P = 0.079).
Discussion: Serum PTH is strictly controlled by ionized Ca levels, though in this study, no correlation was found between PTH and serum Ca in patients with HT, which would indicate that PTH secretion is abnormal in patients with HT. Indeed, serum PTH was inappropriately low in one patient requiring treatment for hypocalcemia. In some cases of primary hypoparathyroidism, an autoimmunity to Ca-sensing receptor have been reported, so any autoimmune mechanisms to parathyroid may be suggested in HT patients.
Conclusion: We showed that some patients with HT might be suffered from low PTH secretion. It would be worth noting that hypocalcemia might be seen during the course of chronic thyroiditis.
19 - 21 Sep 2019
European Society for Paediatric Endocrinology