Course of Ionized Calcium After Thyroidectomy

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.

Combined ionized calcium and PTH evaluation in the management of post-thyroidectomy hypocalcemia

BACKGROUND

The aim of our study was to investigate the postoperative course of calcium and parathyroid hormone (PTH) levels after total thyroidectomy to define a proper and low cost protocol.

METHODS

We studied 144 patients who underwent total thyroidectomy between 2007 and 2010. Ionized calcium was determined preoperatively and on day 1 (POD1), day 2 (POD2) and day 7 (POD7) postoperatively; PTH preoperatively and on POD7. Patients with ionized calcium ≤1.11 mmol/L were considered hypocalcemic and treated only if symptoms, ≤1 mmol/L were treated in all cases.

RESULTS

Ionized calcium and PTH declined postoperative in all patients compared to preoperative levels (P=0.000). Ionized calcium increased on POD7 compared to POD1 and POD2 (P=0.000). All hypocalcemic untreated 30 patients returned normocalcemic on POD7. Thirty-eight hypocalcemic patients were treated but 23 (61%) safely suspended therapy on POD7. We tested PTH and ionized calcium as independent factors of prolonged hypocalcemia (that required therapy beyond 7 days) with the following results (sensitivity, specificity, positive predictive value, negative predictive value and overall accuracy): PTH ≤11 pg/mL (80%, 100%, 100%, 96% and 97%, respectively), ionized calcium ≤1.11 mmol/L (80%, 88%, 59%, 95%, and 87%, respectively) and ionized calcium ≤1 mmol/L (28%, 100%, 100%, 87% and 88%, respectively).

CONCLUSIONS

Our data show that our protocol, including serum ionized calcium on 1^st, 2^nd, 7^th days and PTH on 7^th day after surgery, is safe and low cost and therefore may be useful in the post-surgical management of total thyroidectomy.

Early corrected serum calcium value can predict definitive calcium serum level after total thyroidectomy in asymptomatic patients

INTRODUCTION

Hypocalcemia is the most common complication of thyroidectomy, requiring supplementation as well as prolonged hospitalization. Our study's objective was to determine a corrected calcium (CCa) level on day 1 after thyroidectomy predictive of no calcium and vitamin supplementation.

MATERIALS AND METHODS

A single-center prospective study conducted between January 2012 and July 2015 in 396 patients, consisting of 331 cases of total thyroidectomy, with seven completion surgeries. The data collected were age, sex, type of thyroid surgery, etiology, anatomical pathological analysis, and the need for calcium and vitamin supplementation therapy as well as its duration. CCa levels were analyzed 20 and 30 h after surgery then on days 2 and 3. To determine a cut-off value for CCa, a ROC curve analysis was performed. The population was described in terms of numbers and associated percentages for categorical variables, and mean.

RESULTS

Mean CCa on 20 h after surgery was 2.09 mmol/L (p < 0.001) and 30 h was 2.06 mmol/L p = 0.02. CCa of less than 2.13 mmol/L was predictive of calcium and vitamin supplementation with 56% sensitivity and 97% specificity. On the evening of day 1, the cut-off value for CCa was 2.06 mmol/L with 67% sensitivity and 65% specificity.

CONCLUSION

This prospective study confirms that CCa on the first morning after surgery is reliable when it is more than 2.13 mmol/L. In total, analyzing CCa on day 1 after total thyroidectomy allows the discharge of 70% of patients on the first day after surgery, with no risk of hypocalcemia.

Parathyroid Hormone Assays following Total Thyroidectomy: Is There a Predictive Value?

OBJECTIVES

Parathyroid hormone (PTH) is a risk marker for hypoparathyroidism (hypoPTH). This study aimed to determine the predictive values of early PTH assays carried out at the moment of skin closure (PTH SC), to establish a treatment algorithm, identifying two threshold values. We assessed the reproducibility of this approach with two different immunoassay kits (hypoPTH) after total thyroidectomy, but its practical application is not consensual.

STUDY DESIGN

We conducted a prospective descriptive study, including all patients who underwent a total thyroidectomy between March 2012 and November 2013. Postoperative PTH SC levels, corrected calcium on postoperative days, and occurrence of hypoPTH symptoms were collected.

RESULTS

Of 257 patients, the rate of hypoPTH was 20%. Threshold values to obtain a 100% positive predictive value to identify patients for whom hypoPTH was absolutely certain were: PTH SC <7 ng/L for the Roche kit and PTH SC <4 ng/L for the Beckman-Coulter kit. Threshold values to obtain a 100% negative predictive value to identify patients for whom the absence of hypoPTH was absolutely certain were: PTH SC ≥19 ng/L for the Roche kit and PTH SC ≥9 ng/L the Beckman-Coulter kit.

CONCLUSIONS

A single serum PTH sampled at skin closure is a reliable test to predict hypoPTH after a total thyroidectomy. The use of a threshold based on a 100% negative predictive value enables patients with no risk of hypoPTH to be safely discharged within the first 24 h postoperatively without unnecessary calcium and vitamin treatment. This medication can be given promptly to patients at risk of hypoPTH to limit the occurrence of hypocalcaemia.

WHAT SHOULD BE THE APPROACH TO MODERATE HYPOCALCAEMIA IN THE EARLY PERIOD FOLLOWING TOTAL THYROIDECTOMY?

Context

It is unclear whether treatment is necessary for transient moderate hypocalcaemia occurring after total thyroidectomy; if it is present, it is unclear which treatment modality should be preferred.

Objective

To investigate both the necessity and effectiveness of different treatment approaches of oral and/or intravenous calcium treatment in patients with transient, postoperative, moderate hypocalcaemia.

Design

This is a case control study made between June 2014 and June 2015.

Subjects and Methods

Forty-five patients who had serum calcium levels 6 hours after total thyroidectomy between 7.5-8 mg/dL were divided into three equal groups: an oral calcium administration group, an intravenous calcium administration group and a no-treatment group. Serum calcium and parathyroid hormone levels were measured preoperatively and on postoperative days 1, 2, 5 and 10.

Results

For post-thyroidectomy patients with serum calcium 7.5-8 mg/dL in the early postoperative period, no significant difference in serum calcium or parathyroid hormone was detected between groups.

Conclusions

Follow-up without treatment seems to be the most effective approach for moderate hypocalcaemia occurring in the early period following total thyroidectomy; this suggests that intravenous treatment should be avoided.

Stratifying the Risk of Developing Clinical Hypocalcemia after Thyroidectomy with Parathyroid Hormone

Objective

To identify the risk of clinical hypocalcemia in the first hours after thyroidectomy.

Study Design

Prospective observational study.

Setting

Single-institution tertiary hospital in Madrid, Spain.

Subjects and Methods

A total of 123 patients who underwent total or completion thyroidectomy between June 2010 and March 2012 were included. Pre- and postoperative intact parathyroid hormone (iPTH) levels were obtained. Patients remain hospitalized a minimum of 48 hours until blood calcium stabilized. Calcium and/or vitamin D supplements were prescribed only when signs or symptoms of hypocalcemia developed. Receiver operating characteristic curve analysis was employed to evaluate the postoperative iPTH level and the pre- to postoperative decrease in iPTH levels. Two cutoff values were determined to stratify the risk of developing clinical hypocalcemia into 3 groups.

Results

The areas under the receiver operating characteristic curve were 0.991 for the postoperative iPTH and 0.998 for the decrease in iPTH. An iPTH decrease of 80% had 100% sensitivity to detect patients who developed clinical hypocalcemia, while a postoperative iPTH <3 pg/mL had 100% specificity. Thus, patients with an iPTH decrease ≤80% are at a very low risk of clinical hypocalcemia, and patients with a postoperative iPTH <3 pg/mL are at a very high risk. Patients with an iPTH decrease >80% and a postoperative iPTH ≥3 pg/mL are at intermediate risk. No significant correlation was found between the time when the sample was obtained and iPTH values.

Conclusion

This study stablishes a very accurate test to stratify the risk of clinical postthyroidectomy hypocalcemia based on pre- and postoperative iPTH levels.

Is it possible to limit the risks of thyroid surgery?

OBJECTIVE

Inferior laryngeal nerve (ILN) palsy and hypocalcemia remain the two most frequent major complications after thyroid surgery. Their occurrences may be explained by the influence of factors related to the patient, the surgical procedure, thyroid pathology, or the surgeon's technique. This study aims To assess whether systematically following a rigorous surgical technique during thyroidectomy affects postoperative complications and long-term patient recovery.

METHODS

We conducted a multicenter, cross-sectional study of prospectively collected data in five high-volume referral centers enrolling all patients who underwent thyroid surgery between April 2008 and December 2009. Inferior laryngeal nerve (ILN) palsy and hypocalcemia were systematically assessed during hospitalization based on objective criteria. A six-month follow-up was conducted in cases of early complications. Multivariate regression models were computed to quantify their relationship with potential risk factors.

RESULTS

A total of 3574 thyroid procedures were completed. Non-visualization of the ILN during dissection and a large thyroid mass were major risk factors for permanent ILN palsy (OR, 4.17 and 2.61, p<0.01) and persistent complications after initial injury (OR, 4.17 and 2.42, p<0.05). The presence of thyroiditis on the surgical specimen was an independent risk factor for permanent hypoparathyroidism and poor recovery after initial dysfunction (OR, 1.76 and 1.88, p<0.05).

CONCLUSIONS

Thorough meticulous technique in thyroid surgery is a determinant of ILN function but fails to prevent persistent hypoparathyroidism.

Fatores preditores para hipocalcemia pós-tireoidectomia

OBJETIVO: Avaliar a incidência e os fatores preditores da hipocalcemia e hipoparatireodismo definitivo pós-tireoidectomia. MÉTODOS: Foi dosado cálcio iônico no pré e no pós-operatório (primeiro, segundo e 30ºdia) em 333 pacientes submetidos à tireoidectomia. Naqueles que apresentaram hipocalcemia, as dosagens foram feitas também aos 90 e 180 dias de pós-operatório, quando se dosou também o paratormônio. Os pacientes foram agrupados segundo a presença ou ausência de hipocalcemia e avaliados segundo idade, sexo, função tireoidiana, volume tireoidiano, número de paratireoides identificadas e necessidade de reimplante de paratireoides, tipo de operação, tempo operatório e diagnóstico histopatológico. RESULTADOS: A incidência de hipocalcemia temporária foi de 40,8% (136 pacientes), e hipoparatireoidismo definitivo de 4,2% (14 pacientes). Tireoidectomia total ou reoperação, esvaziamento cervical, hipertireoidismo, tempo operatório e idade acima de 50 anos foram fatores determinantes de incidência significativamente maior de hipocalcemia e hipoparatireodismo definitivo (p<0,05). CONCLUSÃO: os fatores preditores da hipocalcemia pós-operatória incluem idade (>50 anos), tireoidectomia total, reoperação, esvaziamento cervical e tempo operatório. Os fatores preditores do hipoparatireoidismo definitivo pós-tireoidectomia incluíram tipo de operação, diagnóstico histológico e hipertireoidismo.

Calcium management after thyroidectomy: a simple and cost-effective method

OBJECTIVE

Hypocalcemia is one of the principal complications of total or completion thyroidectomy. A number of different protocols for managing this potential complication have been published. Our simple postoperative regimen is described and the safety and cost-effectiveness assessed.

STUDY DESIGN

Case series with planned data collection.

SETTING

Academic medical center.

SUBJECTS AND METHODS

All patients undergoing total or completion thyroidectomy from January 2008 through June 2010 were evaluated. Data collected included age; gender; procedure performed; levels of ionized calcium, parathyroid hormone, and vitamin D; complications; and need for readmission. Standard descriptive statistics were used to summarize these data.

RESULTS

In total, 526 patients had thyroid surgery during the 30-month study period. Of these, 307 underwent completion or total thyroidectomy and were prescribed a 3-week tapering course of calcium carbonate postoperatively. Twenty-three patients (7.5%) experienced symptoms of hypocalcemia that were managed on an outpatient basis with additional doses of oral calcium. Two patients (0.7%) required readmission. The cost of a 3-week regimen of calcium carbonate is approximately $15. This is considerably less expensive than either the cost of overnight admission or published laboratory protocols that are designed to predict the risk of hypocalcemia.

CONCLUSIONS

Prophylactic calcium supplementation without routine laboratory assessment proved to be a safe and cost-effective method of preventing and managing postoperative hypocalcemia following total or completion thyroidectomy.

Influence of chromosome 22q11.2 microdeletion on postoperative calcium level after cardiac-correction surgery

One of the most common constitutional chromosomal abnormalities, 22q11.2 microdeletion (del22q11.2) syndrome has diverse medical complications, such as congenital heart defect, hypocalcaemia, and immune deficiency, which require coordinated multidisciplinary care. Until now, the natural history of hypocalcaemia in chromosome del22q11.2 syndrome had been only partly documented, but there has been limited recognition of the importance of calcium status during the postoperative period when altered calcium status may be associated with serious complications. The goals of our study were (1) to delineate the clinical characteristics of serum calcium in patients with del22q11.2 during the postoperative period and (2) to make recommendations for the investigation and management of del22q11.2 patients after cardiac correction. This study included 22 children diagnosed with del22q11.2 syndrome and 110 children without del22q11.2 syndrome from Nanjing Children's Hospital. Clinical examinations and blood ionized calcium testing were reviewed retrospectively. A comparative study of postoperative calcium levels and complications of del22q11.2 patients with nondeletion patients was performed. Association between postoperative hypocalcaemia and adverse incidents after cardiac correction was also examined. Postoperative hypocalcaemia was observed among 86.4% of del22q11.2 patients and among only 47.3% of nondeletion subjects. The difference was statistically significant (P = 0.0017). Patients with del22q11.2 syndrome also had a much sharper decrease in serum calcium levels during the first 6 h after surgery than nondeletion patients. Postoperative clinical analysis showed that del22q11.2 patients with hypocalcaemia experience more postoperative complications (18 of 19) and greater mortality (5 of 19) after cardiac correction than del22q11.2 patients without normal calcium levels and nondeletion patients. Del22q11.2 children have high susceptibility of hypocalcaemia during the postoperative period, and this low calcium status after cardiac correction may be associated with significant risk of postoperative complications and mortality in patients with del22q11.2.