iPTH Measurement Research Articles

SAT198 Parathyroid Adenoma Masquerading As A Thyroid Nodule

Abstract Disclosure: A. Arida: None. M. Papaleontiou: None. N. Esfandiari: None. Background: The diagnosis of parathyroid adenomas using a neck ultrasound (US) can be challenging when not performed by an experienced radiologist. Additional methods of diagnosis have been implemented to distinguish the differential diagnosis of a nodule in the neck. Clinical Case: A 48-year-old woman with a history of type 2 diabetes, hypercalcemia, and kidney stones presented for evaluation of a lump in the neck of 5 years duration. Prior thyroid US showed a solid hypoechoic nodule superior to the left thyroid lobe measuring 2.2 x 1.2 x 1.1 cm with hypervascularity. Her first FNA biopsy of this nodule reported benign cytology 5 years ago. A parathyroid scintigraphy scan was negative. Repeat FNA biopsy of this nodule showed follicular lesion of undetermined significance (Bethesda category III). Surgical consultation was recommended but she decided to seek a second opinion. A repeat neck US identified a solid vascular 1.6 cm nodule along the anterior margin of the superior left thyroid lobe. Some vascularity was extending from the thyroid tissue into the nodule. It was noted that this may represent an extrathyroidal nodule or arise from the thyroid gland with a score of TIRADS 4. Laboratory tests confirmed primary hyperparathyroidism with an iPTH of 126 pg/mL (normal range, 10-65 pg/mL) and serum calcium of 10.9 mg/dL (normal range, 8.6-10.3 mg/dL). After normalizing vitamin D levels, these values remained elevated. A repeat FNA biopsy of this nodule showed evidence of intrathyroidal parathyroid tissue. Immunostains were performed on the cell block material from the FNA biopsy. Scattered groups of cells were positive for PTH while being negative for TTF-1. Further needle washout for iPTH measurement revealed an iPTH >2000 pg/mL confirming the diagnosis of a parathyroid adenoma. Parathyroid surgery was recommended as per guidelines. Discussion: Once primary hyperparathyroidism is confirmed, the localization of parathyroid adenoma is pursued by a neck US and/or parathyroid scintigraphy. Parathyroid glands are located in the superior poles and in the inferior poles of the thyroid gland but ectopic locations like retropharyngeal, intrathyroidal, and mediastinal are possible. Typical US appearance is oval, solid, well-circumscribed, homogenous, and hypoechoic compared to the thyroid tissue. The color Doppler shows that the blood supply enters at the center and distributes peripherally presenting a “vascular arch” pattern that helps differentiate them from other lesions such as tumors or lymph nodes where the distribution is more centralized. Further needle washout for PTH level can confirm the diagnosis of parathyroid adenoma. Once a parathyroid adenoma is confirmed, minimally invasive parathyroid surgery can be recommended if surgery is indicated. Conclusion: A needle washout for measuring PTH in an FNA biopsy sample should be recommended when it is unclear whether a nodule is a thyroid nodule or a parathyroid adenoma. Presentation: Saturday, June 17, 2023

Management of hypocalcemia following thyroid surgery in children.

Pediatric post-thyroidectomy hypocalcemia management varies significantly from hospital to hospital. The current study has two aims: first, we evaluate demographic data in all pediatric patients submitted to thyroid surgery in our Spanish tertiary hospital over 20 years; secondly, we describe the way that hypocalcemia was diagnosed and treated in that period and present a multidisciplinary protocol for perioperative management of this condition. This is a retrospective and observational study of all patients from 0 to 16 years old who underwent thyroid surgery from 2000 to 2020 at our institution. Demographic, surgical and electrolyte data were recorded from the electronic database. From 2000 to 2016, pediatric thyroid surgery at our institution was performed on 33 patients without a consistent approach or standard electrolyte management. A protocol for perioperative management of these patients was introduced in 2017, and applied to 13 patients. In 2019, the protocol was assessed and updated following a case of symptomatic hypocalcemia. From 2000 to 2016, 47 pediatric patients in all underwent thyroid surgery. We registered eight asymptomatic hypocalcemias. One child developed symptomatic hypocalcemia. Two patients have permanent hypoparathyroidism. Our incidence of general complications following thyroidectomy was low; hypocalcemia was the most prevalent. All the cases of hypocalcemia submitted to the protocol were identified early by iPTH measurements. Intraoperative iPTH levels and percentage drop from baseline could help stratify patients according to their risk of hypocalcemia. High risk patients require immediate postoperative supplementation, including calcitriol and calcium carbonate.

The Timing of Parathyroid Hormone Measurement as an Early Predictor of Postoperative Hypocalcemia Post Total Thyroidectomy: A Prospective Study

Abstract Background: Serum intact parathyroid hormone (iPTH) level is an early marker of post-thyroidectomy hypocalcemia. However, lack of methodological standardization to define timing and cut-off points of iPTH measurement limit its clinical applicability. Here, we evaluated the relationship between two distinct postoperative time sampling and iPTH accuracy on predicting hypocalcemia. Aim of Study: This study was aimed to evaluate the accuracy of iPTH measured after total thyroidectomy to predict postoperative hypocalcemia and to identify patients at risk of postoperative hypocalcaemia who require supplementation treatment, and those not at risk who can be safely discharged without any supplementation treatment. Moreover, combining postoperative PTH and serum calcium levels could result in an accurate prediction of the risk of postoperative hypocal-caemia. Patients and Methods: iPTH was measured within 24h after surgery (iPTH 24h) and on the morning of the 3rd postoperative day (iPTH 3rd PO). Hypocalcemia was defined by levels of total calcium corrected by serum albumin £8.0mg/dL and/or by the presence of symptoms or signs. The most accurate iPTH cut-off point for hypocalcemia prediction was established from a ROC curve comparing both time-points. Results: The study included 40 patients. The mean age was 46.23±9.03 years, 34 were women (85%) and all patients underwent total thyroidectomy. Hypocalcemia occurred in 8 patients (20%), of whom 5 were symptomatic. Lower levels of iPTH 24h and iPTH 3rd PO were associated with postop-erative hypocalcaemia (p < 0.05). Using the ROC curve, the optimal cut-off points were 14.8pg/mL and 14pg/mL for iPTH 24h and iPTH 3rd PO, respectively. The comparison of the AUC showed no significant difference between these two points of evaluation with 98% accuracy for both time points. Conclusions: Serum iPTH levels measured within 24h or on the 3rd morning after surgery are predictors of postoperative hypocalcemia. Notably, both time-points have the same accuracy to predict postoperative hypocalcemia (with different cutoff points).

Etiology and Diagnosis of Permanent Hypoparathyroidism after Total Thyroidectomy.

Postoperative parathyroid failure is the commonest adverse effect of total thyroidectomy, which is a widely used surgical procedure to treat both benign and malignant thyroid disorders. The present review focuses on the scientific gap and lack of data regarding the time period elapsed between the immediate postoperative period, when hypocalcemia is usually detected by the surgeon, and permanent hypoparathyroidism often seen by an endocrinologist months or years later. Parathyroid failure after thyroidectomy results from a combination of trauma, devascularization, inadvertent resection, and/or autotransplantation, all resulting in an early drop of iPTH (intact parathyroid hormone) requiring replacement therapy with calcium and calcitriol. There is very little or no role for other factors such as vitamin D deficiency, calcitonin, or magnesium. Recovery of the parathyroid function is a dynamic process evolving over months and cannot be predicted on the basis of early serum calcium and iPTH measurements; it depends on the number of parathyroid glands remaining in situ (PGRIS)—not autotransplanted nor inadvertently excised—and on early administration of full-dose replacement therapy to avoid hypocalcemia during the first days/weeks after thyroidectomy.

P0898VITAMIN C STATUS MODIFIES PARATHYROID HORMONE SECRETION IN NON-DIALYZED CHRONIC KIDNEY DISEASE PATIENTS

Abstract Background and Aims Among patients with chronic kidney disease (CKD) at predialysis stage, there is a high incidence of secondary hyperparathyroidism. Metabolic changes associated with secondary hyperparathyroidism lead to renal osteodystrophy, including osteitis fibrosa, ectopic calcification, cardiovascular disease, and the risk of death, and serum parathyroid hormone levels are influenced by nutritional variables. Non-dialyzed CKD patients are especially prone to vitamin C deficiency because of dietary restrictions and malnutrition. Vitamin C is an important antioxidant and relates to the development and maintenance of bone tissues. However, the contribution of vitamin C deficiency to parathyroid hormone secretion is unknown. Here, we performed a single-center cross-sectional study in order to assess association of serum vitamin C and parathyroid hormone in non-dialyzed CKD patients. Method We had 280 consecutive patients who underwent serum vitamin C and serum intact parathyroid hormone (iPTH) measurement for screening purposes from January 1st, 2013 to November 30th, 2017. We analysed a total of 128 patients (71.3±11.6 year-old, 80 males) who had an estimated glomerular filtration rate (eGFR) that remained less than 60 mL/min/1.73m2 after 152 patients were excluded because of vitamin C or vitamin D supplementation, age &amp;lt;20 years, dialysis, positive serostatus for HIV, hepatitis B or hepatitis C, chronic infection, or cancer. Results Twenty-three percent of the patients (n=29) had vitamin C levels&amp;lt; 2.0 μg/mL (a range seen in very deficient subjects), 53% (n=68) had levels between 2.0 and 5.5 μg/mL, and 31 patients (24%) had vitamin C levels &amp;gt;5.5 μg/mL, which is considered the upper limit of normal for the healthy population. Log(iPTH) significantly correlated with age (r=-0.238, p=0.00672), log(eGFR) (r=-0.625, p&amp;lt;0.0001), serum calcium (r=-0.609, p&amp;lt;0.0001), and serum phosphate (r=0.41, p&amp;lt;0.0001), and had a tendency to correlate with serum albumin (r=-0.146, p=0.101). Low serum vitamin C was associated with higher serum iPTH (P=0.0005, one-way analysis of variance). In a multiple linear regression model with log(iPTH) as the dependent variable, and age, gender, log(eGFR), serum levels of calcium, phosphate, albumin, and vitamin C as independent variables, the inverse relationship of log(iPTH) and serum vitamin C was confirmed (R2 = 0.568, adjusted R2 = 0.543, P&amp;lt;0.0001), along with other parameters influencing iPTH levels, including age, log(eGFR), serum calcium, and serum phosphate. Low vitamin C levels were also associated with increased serum alkaline phosphatase (r=-0.209, p=0.0179), a further indicator of the impact of vitamin C status on bone metabolism. Conclusion Vitamin C deficiency is prevalent in a significant proportion of non-dialyzed CKD patients. Low vitamin C levels contribute to secondary hyperparathyroidism, leading to increased bone turnover. This novel observation may result from effects of vitamin C on vitamin D metabolism, vitamin D binding in target tissues, and cAMP-linked signalling pathways in bone and parathyroid gland. Therapeutic intervention with supplemental vitamin C for secondary hyperparathyroidism might be a good strategy.

Non-oxidized PTH (n-oxPTH) is associated with graft loss in kidney transplant recipients

Elevated parathyroid hormone (PTH) concentrations were reported to be associated with chronic renal allograft failure. However, measurements of PTH are challenging, because PTH can occur either as non-oxidized (n-ox) or oxidized (ox) PTH. Only n-ox PTH is a PTH receptor agonist. The intact PTH (iPTH) concentrations measured routinely in clinical practice, however, equals non-oxidized PTH (n-oxPTH) plus oxidized PTH (oxPTH). In CKD patients, the majority of the circulating PTH is oxidized. We measured iPTH, oxPTH and n-oxPTH at study entry in 600 kidney transplant recipients (KTRs). They were followed for graft loss for 3 years. Graft loss was defined as need for initiation of renal replacement therapy. Thirty-eight patients had graft loss during the 3 years follow-up. OxPTH correlated very well with iPTH (R2 = 0.997, p < 0.0001), whereas the correlation between n-oxPTH and iPTH was much weaker (R2 = 0.762, p < 0.0001). Compared to KTRs without graft loss, KTRs with graft loss had significantly higher levels of iPTH, oxPTH, and n-oxPTH (p < 0.0001 in all cases). After adjusting for confounding factors in cox proportional hazards analysis, only n-oxPTH, but not oxPTH neither iPTH, was significantly associated with graft loss (Hazard ratio (HR): 1.02, 95% CI: 1.01–1.03, p = 1.84 × 10−3). The very close correlation between oxPTH and iPTH measurements suggests that conventional iPTH measurements most likely describe oxidative stress rather than PTH bioactivity. Only non-oxidized PTH but not oxidized PTH nor intact PTH is associated with graft loss in stable kidney transplant recipients.

A nomogram to predict the likelihood of permanent hypoparathyroidism after total thyroidectomy based on delayed serum calcium and iPTH measurements.

Retrospective studies have shown that delayed high-normal serum calcium and detectable iPTH are independent variables positively influencing outcome of prolonged parathyroid failure after total thyroidectomy (TT). The aim of the present study was to examine prospectively the ability of these two variables to predict permanent hypoparathyroidism in patients under replacement therapy for postoperative hypocalcemia. Prospective observational multicenter study of patients undergoing TT followed by postoperative parathyroid failure (serum calcium <8 mg/dL within 24 h and PTH <15 pg/mL 4 h after surgery). Serum calcium, vitamin D and iPTH were determined before thyroidectomy, 24 h after surgery, at 1 month and then periodically until recovery of the parathyroid function or permanent hypoparathyroidism was diagnosed after at least 1 year follow-up. Some 145 patients with postoperative hypocalcemia were investigated [s-Ca24h 7.5 (0.5) mg/dL]. Hypocalcemia recovered within 30 days in 91 (63%) patients and 54 (37%) developed protracted hypoparathyroidism {iPTH 5.8 [4] pg/mL at 1 month}, of whom 32 recovered within 1 year and 22 developed permanent hypoparathyroidism. Protracted hypoparathyroidism was related to few parathyroid glands remaining in situ (PGRIS). Serum calcium concentration (mg/dL) at 1 postoperative month correlated positively with the rate of recovery (percent) from protracted hypoparathyroidism: <8.5 (20%); 8.5-9 (29%); 9.1-9.5 (70%); 9.6-10 (89%); >10 (83%) (P=0.013). Serum iPTH at 1 month was also higher (7.3 vs. 3.7 pg/mL; P=0.002) in recovered protracted hypoparathyroidism. The combination of both variables predicts the likelihood of recovery of the parathyroid function with >90% accuracy. High-normal serum calcium and low but detectable iPTH concentrations at 1 month after TT were associated with better outcome of protracted hypoparathyroidism. A nomogram combining both variables may guide medical treatment and monitoring of post-thyroidectomy prolonged hypoparathyroidism.

Comparing the values of intact parathormone and 1- 84 PTH to predict hyperparathyroidism in hemodialysis patients.

Background: Secondary hyperparathyroidism (SHPT) is a common complication of chronic kidney disease (CKD) leading high mortality and even long-term morbidity. SHPT is manifested by elevation of parathyroid hormone (PTH) and accurate determining the level of serum PTH is very essential for early diagnosis of SHPT secondary to CKD. It is very important to match the values obtained for intact parathormone (iPTH) and 1– 84 PTH with the minimized measurement bias. Objectives: The present study aimed to first determine the agreement value between the iPTH and 1– 84 PTH measures in patients with hyperparathyroidism secondary to endstage renal disease under chronic hemodialysis. Then, we attempted to determine the best cutoff values for these two measurements for detecting SHPT in such patients. Patients and Methods: This cross-sectional study was conducted on hemodialysis patients. The value of study biomarkers including iPTH and 1– 84 PTH was assessed. Results: A strong positive association was revealed between the two indicators of iPTH and 1-84 PTH (r = 0.800, P < 0.001). The linear association between these two parameters is independent to baseline characteristics including gender, age, body mass index, and medical history. Among all biochemical elements, the value of 1-84 PTH was only associated with serum calcium level negatively (r = -0.267, P = 0.027) and alkaline phosphatase positively (r = 0.359, P = 0.003). Considering iPTH as the reference and according to the area under the ROC curve (AUC), 1-84 PTH had high value to predict hyperparathyroidism (AUC = 0.926, P < 0.001). The best cutoff point for 1-84 PTH to discriminate hyperparathyroidism from normal condition was 60 yielding a sensitivity of 92.3% and a specificity of 79.1%. Among other baseline laboratory parameters, only alkaline phosphatase had an acceptable value for diagnosing hyperparathyroidism (AUC = 0.731, P = 0.001). Conclusions: The measurement of both iPTH and 1-84 PTH is valuable for predicting hyperparathyroidism secondary to CKD, but according to lower cost and comparableeffectiveness of iPTH measurement, this assay may be comparable to 1-84 PTH to predict this consequence.

Parathyroid reimplantation with PR-FaST technique in unselected patients during thyroidectomy. A case series with long term follow up confirming graft vitality and parathormone production

IntroductionParathyroid damage or unintentional excision still affect thyroid surgery and may cause permanent hypoparathyroidism. The only way to recover the excised or ischemic gland functionality is still reimplantation. Many sites of reimplantation have been described, each of one showing both advantages and drawbacks. The aim of this study is to verify results of a new procedure called PR-FaST: Parathyroid Reimplantation in Forearm Subcutaneous Tissue, in a series of unselected patients after long-term follow-up. Materials and methodsFrom January 2013 to October 2015, 296 consecutive total thyroidectomies have been performed) to treat both benign and malignant thyroid diseases. in 42 cases (14.1%), due to an insufficient blood supply or accidental removal, one parathyroid gland was reimplanted with the PR-FaST technique. Post-operative evaluation was carried out by: total serum calcium (Ca), magnesium (Mg) and phosphorus (P) analysis in the 1st and 2nd postoperative days; Ca, Mg, P and serum iPTH from both arms analysis one week after surgery; Ca and iPTH measurement from both arms 1 months, 3, 6 and 12 months after surgery. ResultsWe observed transient hypocalcemia requiring calcium replacement therapy in 5 on 42 (11.9%) patients submitted to PR-FaST. No case of permanent hypoparathyroidism was reported. At 1 week after surgery, only 20 patients (47.6%) showed graft vitality, while the number of patients showing graft vitality arised to 33 (79%) after 1 month and to 39 (92.8%) after three and six months. At 1 year 38 (90.5%) patients showed good graft functionality. Considering levels of serum iPTH from both arms, we observed that in case of graft functionality, samples from reimplanted arm revealed in almost all cases values at least 2–3 folds higher than in non reimplanted arm. ConclusionsResults from this prospective evaluation suggest that PR-FaST is a safe and effective procedure, with potential advantages when compared to other techniques of parathyroid reimplantation, that are mainly the possibility to evaluate graft functionality in the follow-up and the easy and well reproducible technique. Furthermore, it can be applied, when needed, to potentially all patients undergoing thyroidectomy.

Contribution of early SPECT/CT to 99mTc-MIBI double phase scintigraphy in primary hyperparathyroidism: Diagnostic value and correlation between uptake and biological parameters

AimTo evaluate the value of 99mTc-MIBI double-phase scintigraphy (DPS) and early SPECT/CT in the pre-surgical assessment of patients with primary hyperparathyroidism (PHPT). Also, to calculate the correlation between uptake and some biological parameters. Material and methodsForty patients with PHPT were included: 37 solitary adenomas, 1 hyperplasia, and 2 double adenomas. Fifteen patients had ectopic glands.DPS and early SPECT/CT were acquired in all patients. Ultrasound was performed in 31/40. All patients underwent surgery, intra-operative iPTH measurements, and histopathological examinations.Qualitative DPS uptake was assessed and correlated to pre-surgical calcium, iPTH levels, gland weight, and maximum diameter. ResultsIn the planar study, there were 23 positive cases, 8 doubtful, and 9 negatives. With the SPECT/CT, 8/9 negatives cases were located. All doubtful cases were confirmed as positives. Gland location improved in 16 cases (12 ectopic).DPS+SPECT/CT failed to detect a solitary adenoma and at least one gland in three cases of multiglandular disease (MGD). The sensitivity by patient was: DPS 72.5%, DPS+SPECT/CT 90%, and ultrasound 42%.Ultrasound and scintigraphy (DPS+SPECT/CT) were concordant in 16/31 patients. For the rest of them, scintigraphy proved correct in 14/15, and both techniques failed in one case.There was a significant correlation between level of uptake and iPTH level, gland weight, and maximum diameter. ConclusionEarly SPECT/CT improves sensitivity and the locating of parathyroid pathological glands and increases diagnostic confidence. iPTH level, glandular size, and weight are related to the qualitative assessment of 99mTc-MIBI uptake in early DPS.

Contribution of early SPECT/CT to 99mTc-MIBI double phase scintigraphy in primary hyperparathyroidism: Diagnostic value and correlation between uptake and biological parameters.

To evaluate the value of 99mTc-MIBI double-phase scintigraphy (DPS) and early SPECT/CT in the pre-surgical assessment of patients with primary hyperparathyroidism (PHPT). Also, to calculate the correlation between uptake and some biological parameters. Forty patients with PHPT were included: 37 solitary adenomas, 1 hyperplasia, and 2 double adenomas. Fifteen patients had ectopic glands. DPS and early SPECT/CT were acquired in all patients. Ultrasound was performed in 31/40. All patients underwent surgery, intra-operative iPTH measurements, and histopathological examinations. Qualitative DPS uptake was assessed and correlated to pre-surgical calcium, iPTH levels, gland weight, and maximum diameter. In the planar study, there were 23 positive cases, 8 doubtful, and 9 negatives. With the SPECT/CT, 8/9 negatives cases were located. All doubtful cases were confirmed as positives. Gland location improved in 16 cases (12 ectopic). DPS+SPECT/CT failed to detect a solitary adenoma and at least one gland in three cases of multiglandular disease (MGD). The sensitivity by patient was: DPS 72.5%, DPS+SPECT/CT 90%, and ultrasound 42%. Ultrasound and scintigraphy (DPS+SPECT/CT) were concordant in 16/31 patients. For the rest of them, scintigraphy proved correct in 14/15, and both techniques failed in one case. There was a significant correlation between level of uptake and iPTH level, gland weight, and maximum diameter. Early SPECT/CT improves sensitivity and the locating of parathyroid pathological glands and increases diagnostic confidence. iPTH level, glandular size, and weight are related to the qualitative assessment of 99mTc-MIBI uptake in early DPS.

Surgical treatment for patients with hyperparathyroidism

Although parathyroid surgery is not a complicated surgical procedure, enough knowledge of the surgical anatomy and accurate information for localization of involved gland are required from the fact of the variation in the number and the location of the parathyroid gland. Surgical treatment for patients with hyperparathyroidism has been in the transition state from the era of both sides exploration to minimally invasive surgery. In addition, intraoperative radio guide method, intraoperative iPTH measurement, and intraoperative neuromonitoring have been introduced for the safe and reliable operation.

Changes in the Pattern of Primary Hyperparathyroidism in Czech Republic.

Primary hyperparathyroidism (PHPT) is currently the most common endocrine disorder in Czech Republic after diabetes and thyroid diseases particularly in postmenopausal women. Over the past 40 years PHPT has changed from a rare severe disease of the bones and kidneys to common disease with hypertension, peptic ulcer, pancreatitis, easy fatigue and proximal muscle weakness. During 43 years we have examined one of the greatest groups of patients with PHPT. In the early 1970 the estimated incidence of PHPT in former Czechoslovakia was approximately 8 cases per 100 000 persons per year. Our data showed that the incidence of PHPT increased sharply to 24 cases per 100 000 persons per year in same community with the introduction of automated serum calcium and iPTH measurement. The disease is four times more frequent in women as in man. The ratio women to men did not changed since 1981. However the incidence of PHPT changed in Czech Republic from previous years, it develops around the fifth decade of life and is increasingly discovered with advancing age. The incidence of hypertension, diabetes mellitus, cholelithiasis, pancreatitis and peptic ulcer among patients with PHPT is higher as compared with the incidence of these diseases in the general population. However there are still patients suffering from bone and renal complication of PHPT. Removing the adenoma by an experienced surgeon is the first choice of treatment of patients with PHPT. The study offers valuable data on the actual state of hyperparathyroid patients in the Czech Republic.

Postoperative hypoparathyroidism after thyroidectomy: Efficient and cost-effective diagnosis and treatment

To describe a standardized, efficient, and cost-effective protocol for the diagnosis of temporary/persisting postoperative hypoparathyroidism after (total) thyroidectomy. We included 237 consecutive patients who underwent (total) thyroidectomy without central neck dissection for various indications. Serum calcium (sCa) and intact parathyroid hormone (iPTH) levels were measured prospectively on the morning of postoperative day 1 to predict the long-term parathyroid metabolism. On the morning of postoperative day 2, measurements were repeated. Follow-up was performed at 1 and 6 months postoperatively. On the morning of postoperative day 1, patients with iPTH ≥ 15 pg/mL (178/237; 75%) and sCa > 2.0 mmol/L were normocalcemic, and "normal" parathyroid metabolism was predicted. iPTH levels of <10 pg/mL and sCa levels of ≤2.0 mmol/L were present in 33 of the 237 patients ("disturbed" parathyroid metabolism; 14%). A "gray zone" included patients with "uncertain" parathyroid metabolism demonstrating iPTH levels between 10 and 15 pg/mL (26/237; 11%). Patients with "disturbed" and "uncertain" parathyroid metabolism were given oral calcium and vitamin D. On the morning of the second postoperative day, iPTH turned to "normal" in 10 of those 26 (38%) patients, and no further calcium or vitamin D was given. During follow-up, supplemental calcium and vitamin D was able to be stopped in all but 2 patients ("permanent" hypoparathyroidism; 2/237; 0.8%). Measurement of iPTH on the morning after operation allows accurate prediction of postoperative parathyroid function in ≥99% of cases. This simple recommendation is practicable in all surgical units, and is an efficient and cost-effective way to recognize patients who require calcium and vitamin D supplementation.

Avoidance and management of hypoparathyroidism after thyroid gland surgery

Postoperative hypoparathyroidism after bilateral thyroid gland surgery or after interventions for recurrence is defined as intact parathyroid hormone levels (iPTH) < 15pg/ml with simultaneous normal, below normal and markedly decreased serum calcium levels. After bilateral thyroid surgery and after reoperations a single iPTH measurement performed 12-24h postoperatively can be used to predict parathyroid metabolism. Patients with an iPTH level ≥ 15pg/ml may be discharged safely, patients with an iPTH < 10pg/ml must be substituted with calcium and vitamin D and patients with an iPTH between 10 and 15pg/ml (grey zone) may be discharged if a second measurement 48h after surgery documents an iPTH ≥ 15pg/ml. This procedure increases the length of hospital stay. Patients in the (grey zone) must be substituted. The iPTH level and its course determine the necessity, dose and length of calcium and vitamin D substitution.

Effectiveness of an i-PTH Measurement in Predicting Post Thyroidectomy Hypocalcemia: Prospective Controlled Study

PurposeHypocalcemia is the most common complication after total thyroidectomy. The purpose of this study was to determine whether measurement of intact parathyroid hormone (i-PTH) level in thyroidectomy patients could predict hypocalcemia.Materials and MethodsWe performed a prospective study of patients undergoing total thyroidectomy. Serum concentration of i-PTH, total calcium (Ca), ionized calcium (Ca2+), phosphate (P), magnesium (Mg), and albumin were measured preoperatively and at 0 hour, 6 hours, 12 hours, 24 hours, 48 hours, and 72 hours postoperatively.Results108 patients were recruited to the study. A total of 50 patients (46%) experienced hypocalcemia. The serum i-PTH concentration was linearly related to the time of measurement, while concentrations of P, Mg, albumin, Ca, and Ca2+ were not. We compared odds ratios, and found that the concentration of i-PTH at 6 hours post operation was the most closely related to the occurrence of hypocalcemic symptom. On ROC analysis using i-PTH level at 6 hours, an i-PTH level of 10.6 mg/dL was found to maximize both sensitivity and specificity at the same time point.ConclusionWe found that i-PTH was a predictor of hypocalcemia, and that the earliest predictor of hypocalcemic symptoms was an i-PTH concentration lower than 10.6 mg/dL obtained 6 hours after total thyroidectomy.

Could the eZ-SCOPE AN Gamma Camera Replace Intraoperative Measurement of iPTH for PHPT?

Intraoperative intact parathyroid hormone (iPTH) measurements have been proposed as an effective assay in surgery for primary hyperparathyroidism (PHPT). We have demonstrated the efficiency of the use of a hand-held gamma camera, eZ-SCOPE AN, with technetium-99m sestamibi (Tc-MIBI) scintigraphy for navigation surgery for PHPT. The aim of this preliminary study was to assess the possibility that the eZ-SCOPE AN can replace the measurement of intraoperative iPTH in surgery for PHPT. Sixteen consecutive patients with documented primary hyperparathyroidism underwent surgery using this compact camera. iPTH was routinely measured preoperatively and 10 minutes after the complete removal of adenoma. All patients had a well-defined parathyroid lesion identified on preoperative Tc-MIBI. The eZ-SCOPE revealed hyperfunctioning parathyroid glands in all cases. iPTH levels were decreased in all cases after the removal of adenomas. Our results suggest that this gamma camera is useful for confirming complete resection of endocrinologically active tissue in surgery for PHPT. In selective patients with scan-positive cases identified by preoperative Tc-MIBI, the eZ-SCOPE may replace the intraoperative iPTH assay in surgery for PHPT.

Applicability of imediate, late or serial intact parathyroid hormone measurement following total thyroidectomy

Hypocalcemia is the most common complication after total thyroidectomy. Intact parathyroid hormone (i-PTH) testing is a proven effective method to detect patients at risk for postoperative symptomatic hypocalcemia. However, there is still uncertainty as to the timing of i-PTH testing in a clinical setting. ObjectiveThis study looked into the correlation between serum i-PTH levels measured at different times after total thyroidectomy and the risk of symptomatic hypocalcemia. MethodsThis retrospective case series studied a group of 110 consecutive for hypocalcemia and intact parathyroid hormone (PTHi) levels four and twelve hours following total thyroidectomy. Statistical analysis was used to evaluate the performance of isolated and serial i-PTH measurements to determine the likelihood of symptomatic hypocalcemia. ResultsI-PTH is highly sensitive (90.3%-96.8%) and specific (77.2%-87.3%) for symptomatic hypocalcemia. There was no significant difference in the sensitivity levels of the tests done four and twelve hours after surgery or in a serial fashion. However, the 12-hour i-PTH level was more specific (p < 0.0007). ConclusionSingle i-PTH testing done 12 hours after total thyroidectomy may be used as a screening test to detect patients at risk for symptomatic hypocalcemia.

Serum Intact Parathyroid Hormone Level After Total Thyroidectomy or Total Thyroidectomy Plus Lymph Node Dissection for Thyroid Nodules: Report From 296 Surgical Cases

BackgroundTransient hypocalcemia is one of the postoperative complications of thyroidectomy for thyroid nodules, and intraoperative and postoperative intact parathyroid hormone (iPTH) assays are used to predict postoperative hypocalcemia.ObjectivesThe current study was conducted to evaluate a single serum iPTH measurement on postoperative day 1 (POD 1) as a means to predict hypocalcemia occurrence after total thyroidectomy (TT).Patients and MethodsThe subjects consisted of 36 patients who underwent TT and 260 patients who underwent TT plus lymph node (LN) dissection for thyroid nodules treatment. The TT performance procedure to prevent postoperative hypoparathyroidism combines parathyroid gland preservation in situ with autotransplantation of resected or devascularized parathyroid glands. The patients’ serum iPTH level was measured on POD 1, and their serum calcium level was measured on POD 1 and on POD 3 while they were still inpatients. The serum iPTH level was subequently measured at each outpatient clinic visit until it recovered to the normal range.ResultsHypoparathyroidism after TT and TT plus LN dissection was ultimately diagnosed in a total of 229 patients, and in 69 of them hypocalcemia was diagnosed on POD 1. All of the 69 patients diagnosed with hypocalcemia received calcium and vitamin D supplementation therapy. The serum iPTH level of 67 of 229 patients was within normal range on POD 1, and four of them developed hypocalcemia on POD 1. Permanent hypoparathyroidism developed in 37 of 296 patients after undergoing TT or TT plus LN dissection for thyroid nodules in the hospital.ConclusionsA single serum iPTH measurement on POD 1 is useful to determine whether or not to start calcium and vitamin D supplementation in order to maintain normocalcemia after surgery.

Clinical analysis for 51 cases of primary hyperparathyroidism

Objective To study clinical characteristics,causes of misdignosis and diagnostic and therapeutic methods for primary hyperparathyroidism (PHPT).Methods Retrospective analysis was done for 51 patients of PHPT,47 confirmed by biopsy after surgical operation and 4 without operation diagnosed based on their serum levels of calcium,alkaline phosphatase ( ALP),intact parathyroid hormone ( iPTH ),and computed tomography (CT) or 99mtechnetium sestamibi (99mTcMIB1) imaging at the First Affiliated Hospital of Sun Yat-sen University,Guangzhou during June 1997 to November 2010.Results Bone-related complications were the most common clinical manifestation,accounting for 51％ (26/51 ) of the cases,and adenoma,a benign,enlarged and hyperactive parathyroid gland,in 34 of 47 cases ( 72％ ).In orthotopic lesions,the right inferior was affected in 19 of 46 cases (41％),followed by the left inferior in 13 cases (28％),while 5 of 51 cases (10％) with ectopic parathyroid gland.PHPT was easily misdiagnosed as urolithiasis,rheumatic disease,primary osteoporosis,etc,accounting for 92％ of the cases in our study.Preoperative serum levels of calcium,ALP and iPTH in the patients varied with their clinical type and pathological classification,the highest in patients with urolithiasis-bone-related complications [ (3.22 ±0.35) mmol/L,(1455 ± 1091 ) U/L and (1669 ± 515 ) ng/L,respectively ] and in patients with parathyroid carcinoma [ (3.46 ± 0.40) mmol/L,( 1410 ± 426) U/L and ( 1861 ± 768) ng/L,respectively ].Sensibility of preoperative localization diagnosis using ultrasonography,CT and 99mTcMIBI was 88％ (35/40),97％ (30/31) and 97％ (31/32),respectively.Conclusions PHPT is frequently misdiagnosed as other diseases.Measurement of serum calcium should be included in routine physical examinations,supplemented with measurement of serum ALP and iPTH,as well as medical imaging,which can help avoid misdiagnosis.CT combined with 99mTcMIBI imaging can improve accuracy of preoperative localization diagnosis. Key words: Hyperparathyroidism, primary ( PHPT ) ; Diagnostic technique; Endocrine disease; Diagnosis, differential; Treatment