Prediction of post-idroidectomy hypocalcemia through rapid PTH determination

Gonzalo Gutiérrez Fernández; Antonio López Useros; Pedro Muñoz Cacho; Daniel Casanova Rituerto

doi:10.1016/j.ciresp.2020.05.009

Prediction of post-idroidectomy hypocalcemia through rapid PTH determination

Cir Esp (Engl Ed). 2021 Feb;99(2):115-123. doi: 10.1016/j.ciresp.2020.05.009. Epub 2020 Jun 7.

[Article in English, Spanish]

Authors

Gonzalo Gutiérrez Fernández¹, Antonio López Useros², Pedro Muñoz Cacho³, Daniel Casanova Rituerto²

Affiliations

¹ Servicio Cirugía General. Unidad Cirugía Endocrino-Metabólica. Hospital Universitario Marques de Valdecilla, Santander, España. Electronic address: gonzalo.gutierrez@scsalud.es.
² Servicio Cirugía General. Unidad Cirugía Endocrino-Metabólica. Hospital Universitario Marques de Valdecilla, Santander, España.
³ Unidad Docente de Medicina Familiar y Comunitaria, Servicio Cántabro de Salud, Santander, España.

PMID: 32522336
DOI: 10.1016/j.ciresp.2020.05.009

Abstract

Introduction: Hypocalcemia is the most frequent complication after thyroidectomy. The aim of this work is to identify biochemical risk factors of hypocalcemia using quick perioperative (pre and post-thyroidectomy) intact parathyroid hormone (PTHi) and postoperative calcemias.

Methods: In a consecutive series of 310 total thyroidectomies, samples of quick PTHi at the anaesthetic induction and 10 minutes after surgery, together with serum calcemias every 12 hours were obtained. The sensitivity, specificity, positive and negative predictive value are analyzed and related to hypocalcemia. A control group of hemithyroidectomies is also analyzed to compare the effects of surgery on PTH secretion.

Results: Of the 310 patients, 202 (65.1%) remained normocalcemic and asymptomatic (group A), 108 (34.9%) presented hypocalcemia (Group B), requiring oral calcium (79 symptomatic). After analysis of several cut-off points, combining a PTHr drop gradient of 60% or calcemia inferior to 7.4 mg/dl at 24 hours, a sensitivity of 100% is achieved without leaving false negatives. Compared to the control group, there is a significant difference with respect to the post-operative calcemias and PTHr, p < 0.001.

Conclusions: Total thyroidectomy affects parathyroid function with evident decrease in rPTH and risk of hypocalcemia. The combination of PTHr decrease of 60% or less than 7.4 mg/dl calcemia at 24 hours gives a 100% sensitivity for predicting patients at risk of hypocalcemia.

Keywords: Hipocalcemia; Hypocalcemia; PTH thyroidectomy; PTH tiroidectomía; Parathyroid hormone; Paratohormona.