Clinical study on the status of transient thyrotoxicosis after surgery for secondary hyperparathyroidism patients with end-stage renal disease

Background: Secondary hyperparathyroidism (SHPT) is a common complication of end-stage renal disease (ESRD)，and part of SHPT patients need receive parathyroidectomy (PTX). However, as an important postoperative complication of SHPT, thyrotoxicosis has received little attention. Therefore, in this article, we aimed to study the status of transient thyrotoxicosis after PTX for SHPT patients with ESRD and normal thyroid function. Methods: A total of 36 SHPT patients with preoperative normal thyroid function, normal thyroglobulin(Tg) and normal thyroid antibodies receiving PTX were enrolled from the Department of Endocrine and Breast Surgery, the First Affiliated Hospital of Chongqing Medical University, from January 2017 to January 2019. Tg, high sensitivity thyrotropin stimulating hormone(sTSH), triiodothyronine(T3), free triiodothyronine(fT3)，thyroxine(T4) and free thyroxine(fT4) were evaluated the day before PTX and on day 1, 3 and 5 after PTX. Besides, all enrolled patients were evaluated whether there are symptoms associated with thyrotoxicosis. Results: Among the 36 SHPT patients, 3 case (8.3%), 14 cases (38.9%) and 24 cases (66.7%) had suffered thyrotoxicosis at the first, third and fifth day after surgery, respectively. Serum FT4 level increased significantly (＞1.5 times higher than the normal maximum) from pre-operation (0.66±0.14 ng/dl, normal range: 0.59-1.25ng/dl) to the third day after operation (2.13±2.16 ng/dl, p＜0.001) and then gradually decline, but still higher than the normal maximum on day 5 after surgery (1.40±0.59 ng/dl, p＜0.001). The frequencies of serum sTSH lower than the normal level gradually increased from the first day（11.1%） to fifth day （66.7%） after surgery. Serum Tg level increased significantly (＞4 times higher than the normal maximum) from pre-operation (8.43±6.26, normal range: 0.00-50.03ng/ml)to the first day after operation 213.07±157.69, p＜0.001) and then gradually decline, but still relatively higher than the normal maximum on day 5 after surgery (67.70±97.43ng/ml, p＜0.001). Conclusion: Transient thyrotoxicosis is a common postoperative complication of parathyroidectomy for SHPT patients with ESRD and normal thyroid function, and it is necessary for clinicians to evaluate the perioperative thyroid function to make early diagnosis and appropriate prevention and treatment of thyrotoxicosis.