A “safe and effective” protocol for management of post-thyroidectomy hypocalcemia

Definition and diagnosis of postsurgical hypoparathyroidism after thyroid surgery: meta-analysis

Background

Postsurgical hypoparathyroidism (PH) is the most frequent complication after thyroid surgery. The aim of this systematic review and meta-analysis is to summarize a unifying definition of PH and to elucidate the best possible approach for early detection of PH.

Methods

A systematic review of the literature according to the PICO framework using Embase, PUBMED and the Cochrane library was carried out on 1 December 2021 followed by analysis for risk of bias, data extraction and meta-analysis. All studies addressing the definition of postoperative hypoparathyroidism and/or diagnostic approaches for early detection and diagnosis were included. Case reports, commentaries, non-English articles, book chapters and pilot studies and reviews were excluded.

Results

From 13 704 articles, 188 articles were eligible for inclusion and further analysis. These articles provided heterogeneous definitions of PH. Meta-analysis revealed that postoperative measurements of parathormone (PTH) levels have a higher sensitivity and specificity than intraoperative PTH measurements to predict PH after thyroid surgery. None of the timeframes analysed after surgery within the first postoperative day (POD1) was superior to predict the onset of PH. PTH levels of less than 15 pg/ml and less than 10 pg/ml are both reliable threshold levels to predict the postoperative onset of PH. A relative reduction of mean(s.d.) PTH levels from pre- to postoperative values of 73 (standard deviation 11) per cent may also be predictive for the development of PH. The estimation of calcium levels on POD1 are recommended.

Conclusion

PH is best defined as an undetectable or inappropriately low postoperative PTH level in the context of hypocalcaemia with or without hypocalcaemic symptoms. PTH levels should be measured after surgery within 24 h. Both threshold levels below 10 and 15 pg/ml or relative loss of PTH before/after thyroid surgery are reliable to predict the onset of PH.

Thyroidectomy with and without laryngectomy: Differences in post-operative hypocalcemia and management

BACKGROUND

Total laryngectomy (TL) with thyroidectomy can pose significant risks to parathyroid function, and variance in rates of post-operative hypocalcemia (POH) based on extent of thyroidectomy have not been previously reported. Our objective is to identify the rates of hypocalcemia and hypoparathyroidism in TL+/-thyroidectomy and compare this to matched thyroidectomy alone cohorts.

METHODS

Multi-institutional retrospective chart review of patients treated surgically for laryngeal cancer with TL or benign/malignant thyroid disease with thyroidectomy at regional tertiary care centers in New Orleans and Baton Rouge, Louisiana from 2016 to 2019. Cases were evaluated for post-operative and post-discharge calcium and parathyroid hormone levels, post-operative and long-term calcium supplementation, and intraoperative parathyroid identification and management.

RESULTS

101 TL and 319 thyroidectomy patients' charts were reviewed. Regression analysis revealed increased odds of hypocalcemia and hypoparathyroidism in TL + TT versus TT alone (OR 10.7, OR 16.5, p < 0.001, respectively). TL + HT versus HT alone had increased odds of hypoparathyroidism (OR 1.6, p < 0.001). TL with any thyroidectomy compared to TL alone demonstrated both increased odds of hypocalcemia and hypoparathyroidism (OR 4.4 p = 0.009, and OR 4.5 p = 0.05). Odds of requiring long-term calcium supplementation were significantly increased with the addition of thyroidectomy across all groups. TL + TT was 8 times as likely (p = 0.002) and TL + HT was 5.3 times as likely (p = 0.001) to require long-term calcium supplementation compared to TL alone.

CONCLUSIONS

Thyroidectomy combined with TL demonstrates marked increased risk of parathyroid dysfunction and resultant POH. Despite improved visualization of soft tissue anatomy with TL, risk of parathyroid injury in these settings requires special attention to extent of parathyroid dissection and potential devascularization to reduce long-term sequelae of hyperparathyroidism. Therefore, post-operative calcium monitoring after TL is necessary and should resemble the long-standing stringent protocols that already exist for monitoring in thyroidectomy populations.

Outcome of parathyroid function after total thyroidectomy when calcium supplementation is administered routinely versus exclusively to symptomatic patients: A prospective randomized clinical trial

PURPOSE

Current guidelines for calcium supplementation for parathyroid function recovery after thyroidectomy are based on low-quality evidence. The present trial compared the effects of oral calcium and vitamin D supplementation on the recovery of parathyroid function when administered routinely or exclusively to symptomatic patients.

METHODS

This prospective, randomized, open-label clinical trial analyzed 203 patients who underwent total thyroidectomy and developed hypoparathyroidism on postoperative day 1 (POD1) with median age of 41 years and proportion of women of 77.8%. Participants were randomized to group A (calcium and vitamin D supplementation administered only to symptomatic patients) and group B (routine supplementation). The primary outcome was the incidence of protracted hypoparathyroidism in the two groups. Secondary outcomes included risk factors for postoperative protracted hypoparathyroidism and the incidence of symptomatic hypocalcemia.

RESULTS

The incidence of protracted hypoparathyroidism was not significantly different between group A and group B (11 of 99 vs. 17 of 104, P = 0.280). Parathyroid hormone (PTH) in group B exhibited a better recovery tendency. The incidence of postoperative symptomatic hypocalcemia in group B was significantly lower than group A (26.92% vs. 42.42%, P = 0.020). Independent factors predicting protracted hypoparathyroidism included sex, preoperative serum calcium, and POD1 PTH.

CONCLUSION

Calcium and vitamin D supplementation administered exclusively to symptomatic patients achieved the same effect on protracted hypoparathyroidism as routine supplementation. However, routine supplementation significantly reduced postoperative hypocalcemia. Extra attention is necessary in female patients with high preoperative serum calcium and patients with low POD1 PTH.

TRIAL REGISTRATION

Chinese Clinical Trial Registry (ChiCTR), ChiCTR1900022194. Registered March 30, 2019.

Endocrine Surgery: Management of Postoperative Complications Following Endocrine Surgery of the Neck

Cervical endocrine operations include parathyroidectomy, thyroid lobectomy, thyroidectomy, central neck dissection, and lateral neck dissection. The vital structures at risk include the recurrent laryngeal nerves to the intrinsic muscles of the larynx, additional cranial nerves, parathyroid glands essential for calcium homeostasis, aerodigestive structures, and great vessels. Here, the authors discuss complications of endocrine neck surgery, including cervical hematoma and other fluid collections, hypocalcemia from hypoparathyroidism, and nerve injuries, along with their prevention, mitigation, and management. Significant and permanent morbidity can result, but fortunately the overall rate of complications remains low, especially when surgery is performed by high-volume surgeons.

The Optimal Parathyroid Hormone Cut-Off Threshold for Early and Safe Management of Hypocalcemia After Total Thyroidectomy

OBJECTIVE

To define optimal intact parathyroid hormone (iPTH) cut-off threshold predictive of hypocalcemia after total thyroidectomy for safe and effective postoperative management.

METHODS

This prospective single center study was done in 2 phases. In phase I, predictors of symptomatic hypocalcemia were analyzed and the receiver operating characteristic curve was used to define the optimal iPTH cut-off threshold predictive of hypocalcemia. Phase II studied giving prompt prophylactic supplemental calcium and vitamin D to all patients who had iPTH levels below the calculated threshold, while phase I patients were given prompt selective supplementation if they had postoperative hypocalcemia or symptoms.

RESULTS

Univariate analysis of patients in phase I showed that postoperative iPTH was the only significant variable that can predict symptomatic hypocalcemia. Using receiver operating characteristic curve and Youden index, the confirmed optimal cut-off threshold predictive of hypocalcemia was iPTH 19.95 pg/mL, with area under the curve of 0.903, 100% sensitivity, negative predictive value, and highest Youden index, while iPTH 15 pg/mL and iPTH 10 pg/mL were less optimal. Symptomatic hypocalcemia occurred in 30% of the phase I cohort who received selective supplementation versus 3% of those in the phase II cohort who received prophylactic supplementation. Return to emergency department and need for intravenous calcium were also significantly better in phase II.

CONCLUSION

iPTH cut-off for post-thyroidectomy hypocalcemia was 19.95 pg/mL. Low-risk patients were discharged with no supplementation while all high-risk patients received prompt calcium and vitamin D supplementation, which led to effective hypocalcemia management and safe 24-hour discharge.

Prediction of post-idroidectomy hypocalcemia through rapid PTH determination

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.

Modification, validation and implementation of a protocol for post-thyroidectomy hypocalcaemia

Introduction The management of post-thyroidectomy hypocalcaemia should facilitate early discharge, and reduce risks of hypocalcaemia, readmission and treatment related hypercalcaemia. This paper describes the implementation, evaluation and revision a protocol for the optimal management of this condition. Methods Day 1 parathyroid hormone (PTH) measurements in addition to calcium measurements were commenced following review of the unit's outcomes and literature on post-thyroidectomy hypocalcaemia. Outcomes from a three-year cohort of patients undergoing thyroid surgery helped amend this protocol (revision 1) to reduce biochemical tests, stipulate the need, nature and dose of vitamin D/calcium supplements, and encourage early discharge. This was further validated over seven months to assess compliance, episodes of hyper and/or hypocalcaemia after discharge, readmissions and need for treatment changes. Further revisions were made (revision 2) and implemented. Results The temporary and long-term postoperative hypocalcaemia rates were 29.1% and 3.2% respectively. Repeat calcium measurements on the first day altered management in only 1.4% of cases. The revised protocol was adhered to in 90% of cases. One patient had hypocalcaemia (due to non-compliance) and one had hypercalcaemia. Revision 2 involved reducing the dose of calcium. Conclusions This is a good example of a unit protocol for post-thyroidectomy hypocalcaemia being developed and modified on the basis of the literature and local experience. Day 1 PTH and calcium levels determine the need for treatment and frequency of follow-up visits, facilitate early discharge, reduce risk of over and/or undertreatment, and are good indicators of permanent hypocalcaemia.