Kolahdouzan Mohsen, Shahabi Shahmiri Shahab, Hashemi Seyed Mozafar, Keleidari Behrouz, Nazem Masoud, Mohammadi Mofrad Rastin
Department of Surgery, Faculty of Medicine, Isfahan University of Medical Sciences, Isfahan, Iran.
Iran J Otorhinolaryngol. 2017 Sep;29(94):239-246.
Parathyroid dysfunction leading to symptomatic hypocalcemia is not uncommon following a total thyroidectomy and is often associated with significant patient morbidity and a prolonged hospital stay. The current study aimed at evaluating the comparative predictive role of serum calcium and intact parathyroid hormone (iPTH) for post-thyroidectomy hypocalcemia.
This prospective study was performed in 83 consecutive patients undergoing total thyroidectomy. Laboratory data such as serum calcium, vitamin D level, serum iPTH and serum phosphorus levels before surgery, postoperative calcium, and PTH levels measured after 1 and 6 hours and on the first postoperative day (1POD) were recorded.
Among the 83 patients, the mean (SD) age was 45.87 (12.57) years (range, 21-72 years); 70 (84.3%) patients were female. Final pathology was benign for 47 (56.6%) patients and malignant for 36 (43.4%) patients. In total, lymph node dissections were performed in 19 subjects (22.9%). On histological examination of the specimens, the parathyroid gland was found to have been removed inadvertently in 13 (15.7%) cases. In total, 35 (40.9%) patients developed hypocalcemia after thyroidectomy; receiver operating characteristic (ROC) analysis showed that a cut-off value of 15.39 pg/ml for iPTH, with a decline rate of 73% 1 hour after thyroidectomy is a significant predictor of hypocalcemia (area under the curve [AUC], 0.878; 95% confidence interval [CI], 0.79-0.96, P<0.0001) compared with calcium <8 mg/dl (2 mmol/L) with AUC=0.639; 95% CI, 0.51-0.76); P=0.067).
The current study showed that the decline rate in iPTH is a more reliable factor for hypocalcemia after total thyroidectomy than serum calcium. Patients with a decline rate <73% in iPTH could be discharged at 1POD without supplementation.
全甲状腺切除术后，甲状旁腺功能障碍导致症状性低钙血症并不少见，且常与患者显著的发病率和延长的住院时间相关。本研究旨在评估血清钙和完整甲状旁腺激素（iPTH）对甲状腺切除术后低钙血症的比较预测作用。
本前瞻性研究对83例连续接受全甲状腺切除术的患者进行。记录术前血清钙、维生素D水平、血清iPTH和血清磷水平等实验室数据，以及术后1小时、6小时和术后第1天（1POD）测量的钙和PTH水平。
83例患者中，平均（标准差）年龄为45.87（12.57）岁（范围21 - 72岁）；70例（84.3%）为女性。最终病理结果显示，47例（56.6%）患者为良性，36例（43.4%）患者为恶性。共有19例（22.9%）患者进行了淋巴结清扫。在标本的组织学检查中，发现13例（15.7%）病例甲状旁腺被意外切除。总共有35例（40.9%）患者在甲状腺切除术后发生低钙血症；受试者工作特征（ROC）分析显示，iPTH截断值为15.39 pg/ml，甲状腺切除术后1小时下降率为73%是低钙血症的显著预测指标（曲线下面积[AUC]，0.878；95%置信区间[CI]，0.79 - 0.96，P<0.0001），而血钙<8 mg/dl（2 mmol/L）的AUC = 0.639；95% CI，0.51 - 0.76）；P = 0.067）。
本研究表明，iPTH下降率比血清钙是全甲状腺切除术后低钙血症更可靠的因素。iPTH下降率<73%的患者在术后第1天可不补充钙剂出院。
