Parathyroid hormone and serum calcium levels measurements as predictors of postoperative hypocalcemia in total thyroidectomy

Development of a tool to calculate the probability of hypocalcemia after total thyroidectomy: a prospective study

PURPOSE

This study aimed to evaluate the ability of the percentage of decrease in serum PTH level in the first 8 h after total thyroidectomy (TT) to predict hypocalcemia requiring Ca supplementation and develop a tool to predict it.

METHODS

97 patients who underwent TT with measurement of preoperative parathyroid hormone (PTH) levels were prospectively evaluated 1 and 8 h after TT; postoperative magnesium (Mg2PO) and phosphorus levels were evaluated on the 2nd day after surgery. The percentage of decrease in PTH level 1 h (%dPTH1h) and 8 h (%dPTH8h) postoperatively and predictors of hypocalcemia requiring Ca supplementation were evaluated and an equation was developed to predict this outcome.

RESULTS

%dPTH1h (p = 0.002), %dPTH8h (p = 0.001) and (Mg2PO) (p < 0.01) were isolated predictors of postoperative hypocalcemia requiring Ca supplementation. The data obtained led to the development of two tools to predict this complication.

CONCLUSIONS

The percentage of decrease in PTH level 1 h and 8 h postoperatively and the magnesium level on the 2nd day after surgery were predictors of more severe hypocalcemia, and an auxiliary tool for predicting this complication was developed.

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.

Early Postoperative Parathormone and Calcium as Prognostic Factors for Postoperative Hypocalcemia

BACKGROUND

Postoperative hypocalcemia is one of the most common complications after total thyroidectomy. Parathormone (PTH) and calcium levels, measured several hours after surgery, have been suggested as valuable markers for detecting patients at risk for post-thyroidectomy hypocalcemia. We aimed to determine if early post-surgery PTH and calcium levels can be used for the early identification of patients at risk for symptomatic hypocalcemia.

METHODS

PTH and calcium were measured before surgery and at 10 min and 4 h post-thyroidectomy, in 77 patients. Performance characteristics of PTH and calcium levels and their post/pre-surgery ratios were calculated.

RESULTS

Four-hour calcium was a sensitive (93.75%) but not specific (67.61%) indicator of patients at risk for symptomatic hypocalcemia. The 4-h/pre-surgery PTH ratio was the most accurate (90.81%) and the most specific (94.37%) test to identify patients at risk. Serum calcium at 4-h, 4-h/pre-surgery PTH ratio, and PTH at 10 min post-surgery had the higher diagnostic odds ratios (50.86, 32.85, and 29.04, respectively). The 4-h/pre-surgery PTH ratio also had the highest (0.694) Youden's J statistic.

CONCLUSIONS

Low serum calcium levels 4 h after thyroidectomy and the 4-h/pre-surgery PTH ratio could be valuable additions to everyday clinical practice in post-thyroidectomy patients.

Risk Factors for Low Levels of Parathyroid Hormone after Surgery for Thyroid Cancer: A Single Center Study

Background: Thyroidectomy is the definitive treatment for most patients with thyroid cancer. Hypoparathyroidism is the most frequent complication of thyroidectomy, and its pathogenesis is multifactorial. The aim of this study is to evaluate the patient- and surgical-related risk factors for hypoparathyroidism after surgery for thyroid cancer. Methods: In this retrospective study, patients referred to surgery for thyroid cancer from 2016 to 2019 were enrolled. Preoperative serum calcium and parathyroid hormone (PTH) and postoperative 24 h PTH and calcium levels were evaluated. Demographic data, type of surgery, incidence of hypoparathyroidism and hypocalcemia were recorded for all the patients. Patients were divided into two groups based on post-operative PTH levels (≤12 and >12 pg/mL). Results: A total of 189 patients were enrolled in this study. There were 146 women (87.3%) and 43 men (22.7%), with a mean age of 51.3 years. A total of 79 patients (41.7%) underwent a neck dissection. A total of 59 patients (31.1%) had a postoperative PTH level < 12 pg/mL. Female sex, neck dissection, the yield of lymph node dissection and incidental parathyroidectomy were significantly associated with postoperative hypoparathyroidism. Incidental parathyroidectomy was reported in 44 (23.2%) patients and was correlated with younger age (<40 years) and neck dissection. There was no difference in the rate of post-operative hypocalcemia between patients with incidental parathyroidectomy and those without. Conclusions: Young patients undergoing neck dissection and with incidental parathyroidectomy have the highest risk of postoperative hypoparathyroidism after surgery for thyroid cancer. However, a large proportion of patients without incidental parathyroidectomy may have temporary hypocalcemia, suggesting that impaired blood supply of parathyroid glands during their identification and dissection may play a relevant role.

Role of postoperative intact serum PTH as an early predictor of severe post-thyroidectomy hypocalcemia: a prospective study

BACKGROUND

Post thyroidectomy hypocalcemia is a major sequel of thyroidectomy and continues to trouble the endocrinologists and the endocrine surgeons as there is no ideal predictive marker of hypocalcemia which has the potential to develop into a life-threatening complication. The role of early serum intact parathormone (iPTH) to predict post thyroidectomy hypocalcemia is becoming useful but the literature is still unclear regarding the optimal time of testing and the optimal cut-off value of serum iPTH.

PATIENTS AND METHODS

This is a prospective cohort study of 111 patients who underwent total thyroidectomy in a tertiary care endocrine surgery referral unit. Serum iPTH was measured after 20 min and 4 h of surgery. Receiver-Operator characteristic Curve (ROC) was used to find out of the best cut-off value of S. iPTH 20 min and 4 h after surgery in predicting hypocalcemia.

RESULTS

Hypocalcemia was noted in 60 (54%) out of 111 subjects who underwent total thyroidectomy. The best cut-off values of Serum iPTH to predict hypocalcemia was found to be 4.28 pmol/l at 20 min post total thyroidectomy with a sensitivity and specificity of 81.7% and 51%, respectively. In addition, patients with malignancy or central lymph nodal dissection were significantly over-represented in the hypocalcemia group with serum iPTH above the threshold level of 4.28 pmol/l. Below the cut off level, parenteral calcium supplementation was required in 23% (17/74) subjects while the rate was only 5.4% (2/37) patients when serum iPTH was above the cut-off level.

CONCLUSIONS

The decline of serum iPTH below a specific level after surgery has predictive value together with other factors strictly related to patient, the thyroid disease itself and surgery. The risk of development of hypocalcemia and consequent need for calcium supplementation should be evaluated by clinical assessment along with serum PTH measurement.

Improving the Management of Post-Operative Hypocalcaemia in Thyroid Surgery

Hypocalcaemia is a frequent, and potentially dangerous complication of total thyroidectomy occurring secondary to devascularisation of the parathyroid glands. This quality improvement (QI) project was undertaken in a large Ear, Nose and Throat (ENT) department in the East of England over a one year period. The project aimed to improve postoperative guideline compliance by optimising the recognition and management of patients at risk of hypocalcaemia. This process focussed on improving parathyroid hormone (PTH) and calcium blood testing, prophylactic calcium prescribing and the subsequent monitoring and management of hypocalcaemia.

A baseline audit was conducted to determine the initial guideline compliance. The QI process subsequently involved the introduction of a new intraoperative PTH pathway and the amendment of trust guidelines. In addition, there was a focus on improving clinician awareness of guidelines, junior doctor education, communication between operating surgeons and junior doctors and the optimisation of patient handover.

The project saw a significant improvement in the monitoring of hypocalcaemia (from 22.2% to 83.3% for patients with an intermediate risk of hypocalcaemia) and in the prescribing of prophylactic calcium supplements from 7.5% to 43.5%. The measurement of PTH at four hours improved from 42.5% to 52.2%. By optimising postoperative care, this QI project improved patient safety as well as impacting on the duration, and overall cost, of inpatient stay.

Incidence, Risk Factors, and Clinical Implications of Delayed Hypoparathyroidism on Postoperative Day two Following Total Thyroidectomy for Papillary Thyroid Carcinoma

OBJECTIVE

This study aimed to investigate the incidence rates, risk factors, and clinical implications of delayed hypoparathyroidism on postoperative day 2 (POD-2) after total thyroidectomy in patients with papillary thyroid carcinoma.

METHODS

This study included 410 patients with normal serum intact parathyroid hormone (iPTH) and calcium levels on postoperative day 1 (POD-1) who were classified into 2 groups according to the presence or absence of delayed hypoparathyroidism on POD-2.

RESULTS

Of the 410 patients, 98 experienced delayed hypoparathyroidism on POD-2 (23.9%). The significant risk factors for delayed hypoparathyroidism on POD-2 included female gender, age older than 45 years, central lymph node dissection, increased number of excised lymph nodes, and low POD-1 versus preoperative iPTH ratios. Additionally, delayed hypoparathyroidism on POD-2 was found to be a significant risk factor for hypocalcemia on POD-2 and permanent hypoparathyroidism.

CONCLUSION

Prophylactic calcium supplementation and long-term surveillance for permanent hypoparathyroidism should be considered in patients with risk factors for delayed hypoparathyroidism on POD-2.

ABBREVIATIONS

CI = confidence interval; iPTH = intact parathyroid hormone; OR = odds ratio; POD-1 = postoperative day 1; POD-2 = postoperative day 2; PTC = papillary thyroid carcinoma; ROC = receiver operating characteristic.

A rare case of spondyloarthropathy: Iatrogenic hypoparathyroidism

Hypoparathyroidism is an endocrinopathy that can develop idiopathically, as well as due to reasons associated with genetics, autoimmunity, surgery and radiotherapy. It usually presents with neuromuscular signs and symptoms, including enthesopathy caused by calcification of the ligament and enthesis sites, soft tissue calcification, hypertension, cataract and extrapyramidal findings due to basal ganglia calcification. Hypoparathyroidism-associated spondyloarthropathy (SpA) is a rarely seen clinical entity. Hypoparathyroidism-associated SpA differs from other inflammatory SpAs in that the results for human leukocyte antigen B27 and inflammatory markers are negative and bone density is normal. The symptoms are relieved by calcium and vitamin D, rather than anti-inflammatory drugs. Due to this difference in treatment modalities, the diagnosis of this type of SpA is important. This article presents the case report of a 52-year-old female patient with iatrogenic hypoparathyroidism accompanied by asymptomatic hypocalcemia and SpA clinic.

The prevalence of hypocalcemia following total thyroidectomy. A retrospective study based at King Abdulaziz University Hospital, Jeddah, Saudi Arabia

Objectives:

To estimate the prevalence of hypocalcemia following total thyroidectomy (TT) at a tertiary center.

Methods:

This retrospective study was conducted between 2014 and 2019 at King Abdulaziz University Hospital (KAUH), Jeddah, Saudi Arabia. The study was based at the Department of General Surgery and was approved by the Research Ethics Committee of KAUH. Medical records of 154 patients who had undergone TT were reviewed. Data such as age, gender, level of postoperative calcium at 24 and 48 hours after surgery, parathyroid hormone (PTH) levels, central neck dissection (CCND), histological diagnosis were entered into Microsoft Excel sheets.

Results:

Hypocalcemia occurred more on the second day after surgery in 67.4% of patients. Among them, 83.9% were female and 16.1% were male. The majority of patients were asymptomatic and benign thyroid disease was the most common. There was a significant association between hypocalcemia and the PTH level (p<0.001).

Conclusion:

There was a high prevalence of hypocalcemia on the second day after surgery. Presence of hypocalcemia association with the PTH level. Meticulous surgical technique and preservation of parathyroid vascularity are important in preventing postoperative hypocalcemia.

Frequency of Hypocalcaemia following Total Thyroidectomy

Background & Objective

Patients who undergo Total thyroidectomy are at higher risk for postoperative hypocalcaemia, which can lead to significant short and long term morbidity. The aim of this study was to determine the frequency of postoperative hypocalcaemia undergoing Total thyroidectomy.

Methods

A total of 854 patients who underwent Total thyroidectomy and completion thyroidectomy between January 2003 to December 2016 at Endocrine Surgical unit, Jinnah Postgraduate Medical Centre, Karachi, were included in this retrospective study. Data were obtained for demographics, preoperative diagnosis, postoperative calcium levels, extent of surgery and final surgical pathology.

Results

A total of 854 patients underwent Total thyroidectomy. Of these 87.58% (n=748) were malignant and 12.41% (n=106) were benign. Among the malignant and benign patients, 47.3% (n=404) underwent Total thyroidectomy and 52.69% (n=450) underwent completion thyroidectomy. Overall incidence of transient hypocalcaemia was 7% (n=60) and that of permanent hypocalcaemia was 0.11% (n= 1).

Conclusion

Hypocalcaemia is one of major concern following total- thyroidectomy. Meticulous surgical techniques, identification and preservation of vascularity of parathyroid glands are essential in preventing postoperative hypocalcaemia following total thyroidectomy.