Preoperative PTH as a marker of risk for post-thyroidectomy hypocalcemia

There are no common guidelines to identify the population at risk to develop hypocalcemia preoperatively or early in the postoperative course in thyroidectomized patients, therefore the authors suggest to examine the PTH value preoperatively.

We divided 391 patients in two groups according to the preoperative PTH level (normal, ≤ 72 pg/mL vs. increased >73 pg/mL).

In 92/391 cases (23.52%) preoperative PTH was increased (mean PTH level 112.4+/-24.8 pg/mL; normal range 12-72 pg/mL). Out of these, 43 (46.7%) had hypocalcaemia postoperatively. In 18 out of the 43 patients clinical hypocalcemia also developed. The mean follow-up was of 148+/-13 days. Of the 299 patients with normal preoperative PTH, 127 (42.47%) developed postoperative hypocalcemia (mean calcium level 7.4+/-0.33 mg/dL). In 30 patients it was also clinically evident. The difference in terms of incidence of symptomatic hypocalcemia was statistically significant (increased preoperative PTH 19.5% vs. normal preoperative PTH 10.03% , P=0.036).

All candidates to thyroidectomy should be investigated for preoperative PTH abnormalities.