Risk of Hypocalcemia and the Need to Augment Calcium Supplementation After Total Thyroidectomy

A prospective cross-sectional study on hypocalcemia after total thyroidectomy in patients with Graves' disease: insights on secondary hyperparathyroidism

PURPOSE

To investigate the parathyroid function and calcium (Ca) levels in the secondary hyperparathyroidism (SHPT) state in patients with Graves' disease.

METHODS

We examined 31 consecutive patients with Graves' disease without chronic kidney disease, who were treated with total thyroidectomy. The patients were divided into a normal parathyroid hormone (PTH) group (NPTH group; n = 19) with a PTH level ≤ 65 pg/mL, and a secondary hyperparathyroidism group (SHPT group; n = 12), with a PTH level > 65 pg/mL. The PTH and Ca-related parameters were examined and the risk factors for postoperative hypocalcemia were analyzed.

RESULTS

The preoperative Ca level was significantly lower (2.24 ± 0.06 vs. 2.31 ± 0.07 mmol/L, p < 0.05) in the SHPT group than in the NPTH group. The reduction in PTH, 1,25-dihydroxyvitamin D (1,25(OH)2D), and Ca levels from the preoperative day to the next morning was significantly greater in the SHPT group than in the NPTH group (p < 0.05). When intraoperative factors were included, the decrease in the PTH level alone was significant. SHPT was a significant factor in determining the extent of PTH reduction.

CONCLUSIONS

Hyperfunctioning parathyroid glands in the SHPT state were more susceptible to postoperative PTH reduction, which, combined with low preoperative Ca levels, increased the risk of postoperative hypocalcemia in patients with Graves' disease.

Hungry bone syndrome following thyroid surgery

The diagnosis of hypocalcemia-induced tetany following a total thyroidectomy is not common. However, there is a higher risk in patients with a history of gastric bypass surgery due to their malabsorption condition. This case describes postoperative hungry bone syndrome resulting from chronic malabsorption in a patient with a history of bariatric surgery. It is important to consider alternative treatment options if the initial management proves ineffective. Typically, this is a temporary condition, but it's crucial to prioritize prevention in high-risk patients by providing perioperative calcium and vitamin D supplementation.

A Parathyroid Hormone-guided Calcium and Calcitriol Supplementation Protocol Reduces Hypocalcemia-related Readmissions Following Total Thyroidectomy

OBJECTIVE

To determine the effect of a 4 hour postoperative serum parathyroid hormone (PTH) guided calcium and calcitriol supplementation protocol on the incidence of hypocalcemia and hospital readmissions in patients undergoing total thyroidectomy.

METHODS

This was a single institution, retrospective chart review of patients who underwent total thyroidectomy, 148 had been operated on prior to the protocol implementation and 389 after. Hypocalcemia risk was stratified as low (PTH >30 pg/ml), medium (15-30 pg/ml), and high (<15 pg/ml), using serum PTH values obtained 4 hours postoperatively. Hypocalcemia was defined as a total serum calcium level <8 mg/dl. Baseline demographic and operative characteristics, and postoperative outcome were recorded for both groups. Fisher's exact test or Wilcoxon rank sum test were used to compare the characteristics of the two groups. A multivariable logistic regression model was applied to account for potentially confounding variables.

RESULTS

Postoperative hypocalcemia occurred significantly less frequently in the protocol group compared to the preprotocol group (10.3% vs. 20.9%, P=.002). The reduction in hypocalcemia in the protocol group was observed both in patients with (16.3% vs. 25.6%) and without (8.4% vs. 19.3%) cervical lymph node dissection. There was a significantly lower incidence of hospital readmission events in the protocol group compared to the preprotocol group (1.0% vs. 4.7%, P=.013).

CONCLUSIONS

Compared to a historical cohort, a PTH-guided protocol for calcium and calcitriol supplementation significantly reduces postoperative hypocalcemia and hospital readmission rates, in patients undergoing total thyroidectomy.