Elsevier

Surgery

Volume 131, Issue 5, May 2002, Pages 515-520
Surgery

Original Communications
Low parathyroid hormone levels after thyroid surgery: A feasible predictor of hypocalcemia*

https://doi.org/10.1067/msy.2002.123005Get rights and content

Abstract

Background. Selecting patients with a low risk of hypocalcemia is mandatory if patients are to be discharged on the first day after bilateral thyroidectomy. This study investigated the predictive value of intraoperative parathyroid hormone (PTH). Methods. Thirty-eight patients underwent total or near-total thyroidectomy. Patients with or without biochemical and symptomatic hypocalcemia were compared regarding intraoperative PTH levels and previously suggested risk factors. The accuracy of intraoperative PTH to predict patients at risk for postoperative hypocalcemia was compared with a calcium concentration of less than 2.00 mmol/L (8.0 mg/dL) on the first postoperative day. Results. PTH levels after resection of the second lobe, age, and number of parathyroid glands identified intraoperatively were independently associated with the reduction in serum calcium concentration measured at nadir on the first or second postoperative day. PTH levels after resection of the second lobe were lower among patients who developed biochemical (P <.001) and symptomatic hypocalcemia (P <.01) compared with those who did not. Low levels of intraoperative PTH identified the 3 patients who required intravenous calcium during the first 24 postoperative hours. An intraoperative PTH level below reference range and a calcium concentration of less than 2.00 mmol/L measured 1 day postoperatively both predicted biochemical hypocalcemia with a similar sensitivity (90% vs 90%) and specificity (75% vs 82%). Intraoperative PTH was slightly better than a serum calcium concentration of less than 2.00 mmol/L on postoperative day 1 to predict symptomatic hypocalcemia, with a sensitivity of 71% vs 52% and a specificity of 81% vs 76%, respectively. Conclusions. Parathyroid gland insufficiency is the main determinant of transient hypocalcemia after bilateral thyroid surgery. Low intraoperative PTH levels during thyroid surgery are therefore a feasible predictor of postoperative hypocalcemia. (Surgery 2002;131:515-20.)

Section snippets

Patients

A total of 38 consecutive patients, 6 men and 32 women, with a median age of 35 years (range, 15 to 80 years) were included in the study. The indication for surgery was Graves disease in 26 patients, goiter with symptoms of compression in 10 patients, and Plummer disease and suspected papillary thyroid cancer in 1 patient each. All patients except 1 had a normally functioning thyroid gland preoperatively. Twenty-three patients were treated with antithyroid drugs; 3 of these patients were also

Results

Postoperative serum concentrations of calcium were significantly reduced compared with preoperative concentrations (Table I).

. Total serum calcium and PTH values during and after bilateral thyroid surgery

VariablePreoperativelyAfter induction of anesthesiaAfter resection of first lobeAfter resection of second lobeFirst postoperative daySecond postoperative dayThird postoperative dayFollow-up 4 weeks after surgery
Calcium (mmol/L)2.37 ± 0.092.05 ± 0.14***2.09 ± 0.20***2.17 ± 0.23***2.31 ± 0.11**
PTH

Discussion

Data from the present study confirm that transient hypoparathyroidism is a major contributing factor for hypocalcemia after bilateral thyroid surgery.14, 15, 17 The accuracy of a low intraoperative PTH level to predict biochemical and symptomatic postoperative hypocalcemia was not significantly different from that of the commonly used serum calcium concentration of less than 2.00 mmol/L obtained on the morning after surgery. Most important, however, intraoperative PTH level predicted all

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  • Determination of risk factors causing hypocalcaemia after thyroid surgery

    2019, Asian Journal of Surgery
    Citation Excerpt :

    It should be kept in mind that the more risk of female gender in our study may be based on the heterogeneous distribution of patients between the groups and the high number of female patients. In studies conducted by Kamer E. et al,11 Lindblom P. et al12 and Weiss A. et al,13 the elderly patients were more risky in the development of hypocalcaemia. In contrast to these studies, in studies conducted by Duclos A. et al,6 Cho JN et al7 and Hallgrimsson P et al,14 the development of hypocalcaemia after thyroidectomy was observed more common in young patients.

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*

Reprint requests: Pia Lindblom, Department of Surgery, Lund University Hospital, S-221 85 Lund, Sweden.

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