Clinical and biochemical factors affecting postoperative hypocalcemia after near-total thyroidectomy

The most common complication which occurs after thyroidectomy is postoperative hypocalcemia due to parathyroid gland damage. It usually appears 24-48 hours postoperatively, but there are clinical and biochemical factors which may contribute to its earlier diagnosis.

The aim of this study was to assess clinical and biochemical factors which can influence postoperative hypocalcemia after near-total thyroidectomy.

The material consisted of 103 patients with benign nodular goiter. In all patients the blood samples were taken 4 times and levels of total calcium, magnesium, inorganic phosphorus, parathormone and thyroid-stimulating hormone were measured. One day before surgery and during the first three days postoperatively patients were asked about symptoms of hypocalcemia and the presence or absence of a Trousseau sign was observed.

There was no statistically significant connection between the symptoms of hypocalcemia and the age of patients and preoperative hyperthyroidism. Patients with symptomatic hypocalcemia had longer operating time, resected tissue weighed more and hospitalization time was longer than in patients without symptoms of hypocalcemia. Concomitant occurrence of hypocalcemia and hypomagnesemia postoperatively was found in 16% of patients. Changes in parathyroid hormone concentration measured 10 min after thyroid excision were more sensitive and specific for detecting patients with symptomatic hypocalcemia after surgery than total calcium concentration.

Measurement of intraoperative parathormone level 10 min after thyroidectomy is a highly sensitive and specific factor for detecting postoperative hypocalcemia. If we connect this parameter with some other clinical features, it will be possible to predict postoperative hypocalcemia more accurately and introduce supplementation as early as possible.