甲状旁腺素检测对甲状腺全切除后低钙症状的诊断价值

Role of parathyroid hormone measurement in prediction for symptomatic hypocalcaemia after total thyroidectomy

目的评价甲状腺全切除术后患者甲状旁腺素（parathyroid hormone，PTH）、血钙及其变化对低钙症状的诊断价值。方法回顾性分析2005年1月至2009年5月165例因甲状腺双侧癌、未分化癌、有明显外侵、远处转移或巨大良性病变而行甲状腺全切除或补充全切除术患者的临床资料，对比分析术前、术后PTH，血钙变化，利用受试者工作特征曲线检测PTH及PTH变化对低钙症状的诊断价值。结果165例患者中正常血钙（80例）、低钙血症无症状（49例）和低钙血症伴有症状（36例）的3组患者术后PTH平均值分别为31．0ng／L、19．6ng／L和11．9ng／L，平均降低幅度分别为28．6％、52．6％和78．0％，差异均有统计学意义（P值均〈0．001）。PTH、血钙及其变化对出现低钙临床症状的准确率及阳性预测价值较低，而血钙大于2．0mmol/L、PTH大于15ng／L、PTH降低小于50％对出现临床症状的阴性预测值分别为97．6％、90．3％和96．5％。结论手术前后PTH、血钙及其变化对诊断术后出现低钙症状的准确率及阳性预测值较低，利用血钙大于2．00mmoL／L、PTH大于15ng／L、PTH降低小于50％预测不出现低钙症状的价值较高。对甲状腺全切除术的患者至少应在24h内补充钙剂以减少低钙血症的发生率和低钙症状的严重程度。

Objective To evaluate the role of parathyroid hormone （PTH）and serum calcium in prediction for hypocalcaemia after total thyroidectomy. Methods One hundred and sixty-five patients undergoing total or complete total thyroidectomy were reviewed retrospectively. The indications included bilateral carcinoma, undifferential carcinoma, surroundings invasion, distant metastasis and huge benign lesions. Preoperative and postoperative PTH, calcium concentrations and their decline levels were compared between Jan. 2005 and May 2009. The role of PTH value and decline level predicting for symptomatic hypocalcaemia were analyzed by receiver operator characteristics （ROC） curve. Results After total thyroidectomy, 85 patients （51.5%） developed hypoealcemia. Symptoms were reported by 36 patients （21.8%）. The mean concentration of PTH for normocalcaemia（ 80 cases）, asymptomatic hypocalcaemia （49 cases）and symptomatic patients （36 cases ）were 31.0 ng/L,19. 6 ng/L and 11.9 ng/L,respectively. The mean decline level for the three groups were 28. 6% ,52. 6% and 78. 0% , respectively. PTH value and its decline level had a poor predicting value for symptomatic hypocalcaemia and high negative predicting value for asymptomatic patients. The serum calcium concentration more than 2. 0 mmol/L, PTH level higher than 15 ng/L and PTH decline less than 50% had the good negative predicting value of 97.6% ,90. 3% and 96. 5% ,respectively. Conclusions Postoperative PTH and its decline level were significantly correlated with postoperative serum calcium concentration but had a low accuracy for predicting symptomatic hypocaleaemia. The serum calcium concentration more than 2. 0 mmol/L,PTH level higher than 15 ng/L and PTH decline less than 50% had the good predicting value for asymptomatic patients. Calcium should be routinely supplemented in the first 24 h after total thyroidectomy to reduce the rate of hypocalcemia and the severity of hypocalcemia symptoms.