Minimally invasive parathyroidectomy: 101 consecutive cases from a single surgeon

BACKGROUND: Intraoperative rapid parathyroid hormone (iPTH) assay is changing parathyroid surgery. One surgeon's experience at a tertiary care hospital was followed as minimally invasive parathyroidectomy (MIP) was adopted. STUDY DESIGN: In this prospective case study, patients underwent technitium 99m sestamibi scanning, iPTH monitoring, and MIP. A sestamibi-directed incision was made, and iPTH was measured preincision, preexcision of abnormal gland(s), and at 5- and 10-minute intervals. MIP was complete after gland(s) was excised and iPTH fell to less than 50% of preoperative levels. Routine discharge was on the day of surgery with daily calcium and calcitriol to minimize outpatient hypocalcemia. Secondary and tertiary hyperparathyroidism patients were excluded. RESULTS: From December 1999 to June 2002, 101 patients underwent MIP. Patients were 27% men and 73% women, with two reoperations. Preoperation laboratory results averaged serum calcium 11.08 (normal 8.5 to 10.5 mg/dL) and parathyroid hormone (PTH) 169 pg/mL (normal 10 to 55 pg/mL). Average iPTH values at operative intervals were 152, 151, 68, and 50 pg/mL, respectively. Operation demonstrated 12% of patients had four-gland hyperplasia, 3% had double adenomas, 2% had parathyroid carcinomas, and 83% had single adenomas. Discharge on the day of surgery occurred in 83% of single-adenoma patients. Postoperative laboratory results averaged calcium 9.4 mg/dL (p < 0.001 versus preoperation) and PTH 48 pg/mL (p < 0.001). Fifteen patients (16%) had elevated PTH after operation, but without elevated calcium levels. One patient had persistant hyperparathyroidism. CONCLUSIONS: MIP with iPTH monitoring is a safe and effective means of treating hyperparathyroidism. This approach allows for limited dissection and early discharge for the majority of patients.     

Normalization of intraoperative parathyroid hormone does not predict normal postoperative parathyroid hormone levels

BACKGROUND: Intraoperative intact parathyroid hormone (iPTH) is being used to confirm complete excision of hyperfunctioning parathyroid tissue. It is uncertain whether normalization of intraoperative iPTH levels accurately predicts long-term postoperative iPTH values. METHODS: Fifty-two consecutive patients with primary or secondary hyperparathyroidism underwent parathyroidectomy with measurement of intraoperative iPTH. Ten patients were excluded due to incomplete laboratory follow-up. Follow-up serum calcium and iPTH levels were measured at 1- and 3-month intervals. RESULTS: Before operation, the mean serum iPTH level was 249 pg/mL (SD=208) and mean serum calcium level was 11.4 +/- 0.9 mg/dL (+/- SD). In all but 4 patients, final intraoperative iPTH levels normalized to less than 67 +/- 41 pg/mL (mean, 35 pg/mL). One week after operation, serum calcium levels had returned to normal (mean, 9.4 +/- 1.1 pg/mL), which directly correlated with the final intraoperative serum iPTH values (Pearson correlation, r = -.434; P <.01). By 1 month, all but 2 patients were normocalcemic (mean, 9.4 +/- 0.9 pg/mL) with a mean iPTH level of 74.8 +/- 82 pg/mL. There was no correlation between final intraoperative and postoperative serum iPTH values (r =.099; P <.533). Both patients with persistent hypercalcemia at 1 month had appropriate intraoperative decreases in iPTH values. CONCLUSIONS: Intraoperative serum iPTH levels significantly correlate with postoperative serum calcium levels but not with postoperative serum iPTH levels. There was a 4.8% failure rate in the correction of postoperative serum calcium levels and a 29% failure rate in the normalization of postoperative serum iPTH levels.     

A patient undergoing chronic dialysis whose renal anemia was successfully corrected by treatment with cinacalcet

A 62-year-old female dialysis patient with chronic glomerulonephritis had been receiving hemodialysis therapy for 32 years. In 1985 she underwent a parathyroidectomy for secondary hyperparathyroidism (HPT); however, her parathyroid hormone (PTH) levels gradually increased. Her serum calcium level ranged from 9.0 to 10.0 mg/dL, which caused difficulties in performing vitamin D injection therapy. No parathyroid glands were seen by echography or scintigraphy. On 31 March 2008 her intact PTH (iPTH) level was 895 pg/mL so treatment with cinacalcet 25 mg/day was started. After 3 months her iPTH level decreased to 269 pg/mL and her hemoglobin level increased from 9.3 to 12.9 g/dL. In some cases of severe HPT, anemia improves after parathyroidectomy; however, in this case, cinacalcet improved not only secondary HPT but also anemia.     

Parathyroid graft function after presternal subcutaneous autotransplantation for renal hyperparathyroidism

HYPOTHESIS: Presternal subcutaneous autotransplantation of parathyroid tissue after total parathyroidectomy for renal hyperparathyroidism could be at least as effective as intramuscular grafting, without its complications. DESIGN: Prospective study of a postoperative diagnostic method of monitoring intact parathyroid hormone (iPTH) levels among a cohort of surgical patients, without loss to follow-up. SETTING: Hemodialysis unit in a university hospital. PATIENTS: Twenty-five patients (17 women and 8 men) underwent total parathyroidectomy and presternal subcutaneous autotransplantation for renal hyperparathyroidism at Donostia Hospital, San Sebastián, Spain, between January 1, 2002, and June 30, 2004. MAIN OUTCOME MEASURES: Evaluation of parathyroid graft function by measurement of serum iPTH levels at admission and 24 hours and 1, 3, 5, 15, 30, and 60 weeks after surgery. RESULTS: The mean +/- SD preoperative serum iPTH level was 1302 +/- 425 pg/mL; the iPTH level was undetectable in all patients 24 hours after surgery. Subsequent mean +/- SD iPTH levels obtained were 14 +/- 10 pg/mL after 1 week, 54 +/- 1 pg/mL after 5 weeks, 64 +/- 9 pg/mL after 15 weeks, 77 +/- 8 pg/mL after 30 weeks, and 106 +/- 21 pg/mL after 60 weeks. Autotransplanted parathyroid tissue appears to be adequately functional at week 5 (criterion level of adequate functioning, 50 pg/mL). CONCLUSIONS: Presternal subcutaneous autotransplantation after total parathyroidectomy for renal hyperparathyroidism may be an alternative to avoid musculus brachialis grafting and its complications. Our functional results compare favorably with the published data on other surgical techniques for the treatment of renal hyperparathyroidism. Long-term follow-up of this series is planned.     

Intact PTH assay overestimates true 1-84 PTH levels after maxacalcitol therapy in dialysis patients with secondary hyperparathyroidism.

BACKGROUND: Although the so-called intact parathyroid hormone (iPTH) assay detects not only true 1-84 PTH (1-84PTH) but also large C-terminal PTH fragments, it remains inconclusive whether the 1-84PTH assay is more useful in clinical practice. Previous studies have shown that the results of these two PTH assays in dialysis patients are closely correlated. METHODS: Chronic dialysis patients whose plasma iPTH levels were >400 pg/ml were selected for inclusion in the present study. Following a 4 week wash-out time during which all vitamin D administration was halted, maxacalcitol was intravenously injected at the end of dialysis sessions three times per week for 24 weeks, at an initial dosage of 10 micro g. RESULTS: Ninety-seven patients with secondary hyperparathyroidism were included in our analysis. Their serum calcium levels were elevated from the start levels while phosphate levels remained unchanged. The plasma 1-84PTH levels constantly declined throughout the 24 weeks. Although the patients' plasma 1-84PTH and iPTH levels were closely correlated with each other both at the beginning of the study and after 24 weeks of maxacalcitol therapy, the ratio of 1-84PTH/iPTH consistently decreased throughout the study period (P<0.01). The changes in the ratio were significantly correlated with changes in serum calcium levels. CONCLUSIONS: Twenty-four weeks of intravenous maxacalcitol injection therapy significantly reduced the 1-84PTH/iPTH ratio. Estimated 1-84PTH levels from iPTH levels using a conversion formula obtained before the treatment were 21.0+/-20.4% higher than measured 1-84PTH levels after the therapy. Thus, iPTH measurement has a potential risk to overestimate 1-84PTH levels when evaluating the efficacy of maxacalcitol therapy in dialysis patients with secondary hyperparathyroidism.     

Risk Factors of Severe Hypocalcemia After US-Guided Percutaneous Microwave Ablation of the Parathyroid Gland in Patients with Secondary Hyperparathyroidism

Our aim was to identify potential risk factors associated with severe hypocalcemia (SH) after microwave ablation (MWA) in patients with secondary hyperparathyroidism (SHPT). This retrospective cross-sectional study enrolled 204 consecutive patients (with 387 parathyroid glands) who underwent MWA between July 2015 and May 2018. Clinical parameters, laboratory indices, and parathyroid gland characteristics were analyzed to assess risk factors associated with SH after MWA. SH was defined as serum calcium level lower than 1.875 mmol/L (7.5 mg/dL) after MWA. Two models (I and II) for pre-MWA and post-MWA prediction were established, respectively. In accordance with the KDIGO guidelines, the target value for intact parathyroid hormone (iPTH) less than 300 pg/mL within 7 days after MWA was considered as a successful procedure. The success rate of MWA was 71.6% (146/204). The incidence of hypocalcemia and SH after MWA was 35.8% and 22.06%, respectively. The pre-MWA prediction models I and II showed that high pre-MWA iPTH, a dramatic reduction in iPTH, low pre-MWA serum calcium, multiple ablated gland, and lack of pruritus symptoms were risk factors for developing SH. The accuracy (82.23% versus 83.25% in models I and II, respectively), sensitivity (34.88% versus 44.19%), specificity (95.45% versus 94.59%), positive predictive value (PPV) (68.18% versus 70.37%), and negative predictive value (NPV) (84% versus 85.37%) of both models were promising. The logistic regression fitting of the nomograms showed high prediction efficiency (0.845 and 0.863). High pre-MWA iPTH, dramatic reductions in iPTH, low pre-MWA serum calcium, multiple gland ablation, and no pruritus symptoms were predictors of SH. © 2019 American Society for Bone and Mineral Research.     

Intraoperative monitoring of kinetic total serum calcium levels in primary hyperparathyroidism surgery

BACKGROUND: In the setting of minimal approach Sestamibi-guided parathyroid surgery for primary hyperparathyroidism we evaluated if total serum calcium level monitoring is as valuable as intraoperative parathyroid hormone (iPTH) monitoring. STUDY DESIGN: Prospective open single-blinded efficacy trial of two intraoperative diagnostic monitoring methods (iPTH and total serum calcium level) on a cohort of surgical patients. All patients (n = 35) were undergoing parathyroid surgery at the Department of General Surgery at B Cruces' Hospital, Vizcaya, Spain, between October 1999 and March 2001. Kinetics of serum levels of Ca and iPTH during surgery and time of prediction of cure for each method (measured in the clinic, admission, and intraoperatively, such as induction of anesthesia, and every 5 minutes after removal of adenoma) were analyzed. RESULTS: Hypercalcemia and iPTH levels became corrected in 34 patients. Average serum calcium levels dropped from pathologic 11.07 +/- 0.41 mg/dL (mean +/- standard deviation) to normal values 9.7 +/- 0.82 mg/dL during the first intraoperative determination (minute 5), but mean iPTH decreased from pathologic (192 +/- 98 pg/mL) to normal values (39.93 +/- 25.12 pg/mL) during the third intraoperative determination (minute 15). Serum calcium level at 5 minutes after removal decreased by 100% in 34 patients, but iPTH only showed a similar drop during the third determination at 15 minutes. Frozen sections were conclusive for parathyroid tissue (20.56 +/- 10.3 minutes after removal). CONCLUSIONS: Intraoperative measurement of total calcium level might be an easier and less expensive method than iPTH measurement in the prediction of cure during surgery for primary hyperparathyroidism resulting from adenoma.     

Early prediction of postthyroidectomy hypocalcemia by one single iPTH measurement

BACKGROUND: We prospectively evaluated the possibility to make an early prediction of postthyroidectomy hypocalcemia by postoperative intact parathyroid hormone (iPTH) measurements. METHODS: Fifty-three consecutive patients who underwent bilateral thyroid resection were included; iPTH was measured preoperatively, at the end of the surgical procedure, and at 2, 4, 6, 24, and 48 hours after the operation. Patients who had hypocalcemia (serum total calcium, <8.0 mg/dL) were compared with normocalcemic patients. RESULTS: Sixteen patients experienced hypocalcemia. Six patients experienced symptoms. No significant difference was found between hypocalcemic and normocalcemic patients concerning demographic, pathologic, and preoperative laboratory data, surgical procedure, and intraoperative findings. Postoperative iPTH levels were reduced in hypocalcemic patients at the end of the procedure and at 2, 4, 6, 24, and 48 hours after the operation ( P < .001). IPTH levels below the normal range (<10 pg/mL) at 4 and 6 hours after the operation correctly predicted postoperative hypocalcemia and symptoms in all but 1 patient with a self-limiting, asymptomatic hypocalcemia (serum calcium concentration, 7.8 mg/dL) (specificity, 100%; sensitivity, 94%; overall accuracy, 98%). CONCLUSIONS: One single iPTH measurement reliably can predict, early after thyroidectomy, which patients are prone to clinically relevant postoperative hypocalcemia and necessitate supplementation treatment and which patients are eligible for a safe early discharge.     

帕立骨化醇治疗维持性血液透析患者继发性甲状旁腺功能亢进的疗效观察

目的观察帕立骨化醇对维持性血液透析患者继发性甲状旁腺功能亢进症的治疗效果。方法选择2018年7月至2019年7月对非选择性维生素D受体激动剂(VDRA)疗效不佳或不能耐受拟钙剂或不愿手术治疗的继发性甲状旁腺功能亢进(SHPT)的维持性血液透析患者56例,根据血液全段甲状旁腺素(iPTH)水平将所有患者分为三个组别:A组(300 pg/mL≤iPTH<600 pg/mL)、B组(600 pg/mL≤iPTH<800 pg/mL)、C组(iPTH≥800 pg/mL)。根据体重给予不同剂量的静脉帕立骨化醇注射液,分别检测患者治疗前、初始使用1个月以及达到帕立骨化醇维持剂量时,iPTH、血钙、血磷、钙磷乘积的变化情况。结果患者骨痛、瘙痒、疲乏等症状明显改善。所有患者初始治疗1个月,iPTH达标率为51.8%(29/56),达到帕立骨化醇注射液维持治疗剂量百分比为57.1%(32/56)。患者初始治疗1个月与治疗前相比,iPTH水平显著下降[(718.76±457.56)pg/mL vs.(956.68±375.61)pg/mL,P<0.001],血钙、血磷以及钙磷乘积无明显改变[(2.28±0.23)mmol/L vs.(2.23±0.27)mmol/L,(2.15±0.49)mmol/L vs.(2.29±0.48)mmol/L,(58.49±17.71)mg^2/dl2 vs.(62.90±13.93)mg^2/dl2,P>0.05]。进入维持治疗阶段的患者,维持治疗与初始治疗相比,iPTH水平仍有下降趋势,但差异无统计学意义[(424.82±221.23)pg/mL vs.(517.55±325.77)pg/mL,P>0.05],血钙、血磷以及钙磷乘积比较差异无统计学意义[(2.33±0.20)mmol/L vs.(2.31±0.24)mmol/L,(2.13±0.44)mmol/L vs.(2.00±0.42)mmol/L,(61.24±12.25)mg^2/dl2 vs.(55.76±15.66)mg^2/dl2,P>0.05]。结论帕立骨化醇对非选择性VDRA疗效不佳或不能耐受拟钙剂或不愿手术治疗的维持性血液透析患者SHPT有较好的疗效,明显缓解患者骨痛、瘙痒、疲乏等症状,显著降低iPTH水平,且不增加高钙血症的发生风险。     

Intact parathyroid hormone measurement at 24 hours after thyroid surgery as predictor of parathyroid function at long term

Background

There is no consensus about the usefulness of postoperative intact parathyroid hormone (iPTH) determination to predict permanent hypoparathyroidism (pHPP). We evaluated the value of calcium (Ca²⁺) and iPTH concentration at 24 hours after total thyroidectomy (TT) for predicting pHPP.

Methods

Ca²⁺ and iPTH levels from 70 consecutive patients who underwent TT were measured at 24 hours and 6 months after TT.

Results

Five patients (7.1%) developed pHPP. An iPTH concentration ≤5.8 pg/mL at 24 hours after TT identified patients at risk for pHPP (sensitivity, 100%; specificity, 81.5%), but it was not accurate enough to predict its development (positive predictive value, 30%). Conversely, an iPTH level >5.8 pg/mL predicted normal parathyroid function at 6 months (negative predictive value, 100%). Compared with iPTH, a postoperative Ca²⁺ level ≤1.95 mmol/L was 60% sensitive and 78.5% specific to predict pHPP.

Conclusions

An iPTH concentration >5.8 pg/mL on the first postoperative day rules out pHPP with much better diagnostic accuracy than Ca²⁺. Postoperative iPTH could be helpful in identifying patients at risk for developing pHPP.     

Percutaneous ethanol injection therapy in post-transplant patients with secondary hyperparathyroidism

Persistent hyperparathyroidism is frequent in postrenal transplant patients. Percutaneous ethanol injection therapy (PEIT) is an alternative for treatment of patients with secondary hyperparathyroidism but it was not described in postrenal transplant patients. We report our experience with PEIT to control hyperparathyroidism in the post-transplant period. We performed PEIT under ultrasonographic guidance and local anesthesia in eight patients because of persistent secondary hyperparathyroidism after renal transplantation. Indications for PEIT were: high intact parathyroid hormone (iPTH) levels with hypercalcemia, hypophosphatemia, osteopenia and/or bone pain. All patients had at least one visible parathyroid nodule by ultrasonography. Biochemical assays were performed immediately before PEIT, between 1 and 7 days after last PEIT, and a mean of 8.0 +/- 2.8 months after PEIT. Serum iPTH and calcium levels decreased significantly after treatment and remained unchanged until final control. Serum iPTH decreased from 286.9 +/- 107.2 to 154.6 +/- 42.2 pg/ml (P < 0.01) after PEIT (percentual reduction 36.5 +/- 9.5%). This response was significantly correlated to total ethanol volume used (r: 0.94, P < 0.0001). Hypercalcemia disappeared in six of eight patients treated. Only minor complications were registered. There were no changes in renal function related to the treatment. Our findings show that PEIT is a useful and safe alternative for patients with persistent post-transplant secondary hyperparathyroidism.     

Hypercalcemia due to resistant hyperparathyroidism in renal transplant patients treated with the calcimimetic agent cinacalcet

INTRODUCTION AND AIMS: Calcimimetic agents increase the sensitivity of calcium-sensing receptors of parathyroid glands and suppress both serum calcium levels and parathyroid hormone (PTH). The use of these drugs in patients with a functioning graft suffering from resistant hyperparathyroidism and hypercalcemia is still under investigation. We report seven patients who were treated with the calcimimetic agent cinacalcet. METHODS: The four male and three female patients of 38 to 72 years of age received a renal transplant from 4 to 35 months before cinacalcet treatment. Serum creatinine was 1.2 to 1.8 mg/dL (estimated glomerular filtration rate between 40 and 75 mL/min). Immunosuppressive treatment consisted of interleukin-2 antibody induction therapy, calcineurin inhibitors (cyclosporine or tacrolimus), prednisolone, and mycophenolate mofetil. Mild to severe hyperparathyroidism resistant to vitamin D analog treatment (intact parathyroid hormone molecule [iPTH] 174 to 519 pg/mL) was accompanied by severe hypercalcemia (Ca >11 mg%). To date the patients have completed 3 to 18 months of therapy. Cinacalcet 30 mg/d was initially administered. RESULTS: This treatment resulted in a rapid decrease in total serum calcium (8.6 to 9.2 mg/dL) while PTH showed a milder, progressive decrease. Having controlled calcium levels, 1alpha OH vitamin D (0.25 microg/d per os) was added to the treatment, which resulted in a further decline of iPTH without producing an increase in serum calcium concentrations (median initial iPTH value 401 pg/mL, median value after treatment 176 pg/mL). Therapy was well tolerated without hypocalcemic events. CONCLUSION: Cinacalcet offered a better holistic treatment approach to such patients.     

Significance of monitoring Bio-Intact PTH (1-84) during parathyroidectomy for secondary hyperparathyroidism

BACKGROUND: The Bio-Intact PTH (1-84) assay has recently been developed to specifically measure the intact PTH (1-84) molecule, and in this study we used it to investigate sequential changes in serum Bio-Intact PTH (1-84) levels during parathyroidectomy for secondary HPT. MATERIAL AND METHODS: The subjects of this study were 70 patients (41 women, 29 men) who underwent parathyroidectomy between April 2002 and March 2005. Ethylene diamine tetraacetic acid serum samples were drawn via a peripheral venous catheter after induction of anesthesia (basal), and at 5, 10, and 30 min after diseased glands excision. Serum active PTH (1-84) was measured by the Bio-Intact PTH (1-84) assay, which is a two-site chemiluminometric assay. RESULTS: When 4 or more diseased parathyroid glands were removed, the basal of Bio-Intact PTH (1-84) level in patients without persistent HPT (52 cases) was 539 +/- 355 pg/mL. The level of the Bio-Intact PTH (1-84) at 30 min after sufficient parathyroidectomy had decreased to less than 45 pg/mL, whereas the Bio-Intact PTH (1-84) level in patients with persistent HPT at 30 min was greater than 45 pg/mL (3 cases). After removal of three or fewer diseased parathyroid glands (15 cases), the Bio-Intact PTH (1-84) at 30 min in patients without persistent HPT (13 cases) was less than 45 pg/mL. The 2 patients whose the Bio-Intact PTH (1-84) at 30 min was greater than 45 pg/mL underwent reoperation, and residual enlarged parathyroid gland in the neck was removed. CONCLUSIONS: The Bio-Intact PTH (1-84) level at 30 min after parathyroidectomy seems to be useful for judging whether the parathyroidectomy is complete irrespective of the number of glands removed from patients with secondary HPT. When only three diseased parathyroid glands are removed, the surgeon can decide whether to continue or stop neck exploration according to the level of Bio-Intact PTH (1-84) at 30 min.     

Parathyroidectomy: new criteria for evaluating outcome

Following successful parathyroidectomy, subjective improvement in recognized symptoms and in the overall "well being" of asymptomatic primary hyperparathyroid patients has been well documented. Because quantitative methods for measuring parathyroid hormone (PTH) and normal reference ranges of serum calcium have changed in recent years, a revised biochemical criteria for evaluating postoperative outcome has become necessary. Two hundred seventy-one selected patients were followed for an average of 6.3 years after parathyroidectomy. Although 257 patients had serum calcium levels <10.6 mg/dL during the entire follow-up period, 15 per cent of them had elevated intact PTH (iPTH) levels. Fourteen patients had calcium levels > or =10.6 mg/dL at some point during follow-up, with nine patients (64%) showing high iPTH levels and eight (57%) of them developing recurrent hyperparathyroidism (calcium > or =11 mg/dL and iPTH > or =68 pg/mL). Of the 14 remaining patients, 5 had hypercalcemia with normal iPTH levels. In patients with successfully treated primary hyperparathyroidism, the recommended annual follow-up is: 1) monitor total serum calcium only if serum calcium level is <10.6 mg/dL, or if serum calcium level is > or =10.6 mg/dL; and 2) monitor serum calcium and PTH levels, because these patients have an increased incidence of hyperfunctioning parathyroid glands, which may point to late recurrence.     

Intraoperative parathyroid hormone measurement in patients with secondary hyperparathyroidism

HYPOTHESIS: Secondary hyperparathyroidism decreases renal clearance of parathyroid hormone (PTH). OBJECTIVE: To determine whether rapid PTH assays can be used to predict the success of a total parathyroidectomy to treat symptomatic secondary hyperparathyroidism. DESIGN: Case series from August 1 to December 31, 2000. SETTING: Tertiary referral center. PARTICIPANTS: Patients with symptomatic secondary hyperparathyroidism (n = 24) who underwent total parathyroidectomy and autotransplantation were included in the study. INTERVENTIONS: Blood samples for rapid PTH analyses were drawn from an indwelling catheter at the induction of anesthesia (baseline) and before (0 minutes), 10 minutes, and 30 minutes after the removal of the last parathyroid gland. Regular intact PTH (iPTH) assays were conducted later. MAIN OUTCOME MEASURE: If a patient's regular iPTH levels were below 65 pg/mL at 1 week or 3 months postoperatively, the operation was considered successful. RESULTS: All 24 patients had successful operations. Rapid PTH and regular iPTH correlated significantly at 0, 10, and 30 minutes. Rapid PTH levels decreased significantly at each time period and were 176 +/- 40.9 pg/mL (mean +/- SE) at 10 minutes. The percentage decrease in rapid PTH levels was 39.5% +/- 12.7% at 0 minutes, 75.1% +/- 6.2% at 10 minutes, and 91.0% +/- 0.1% at 30 minutes (mean +/- SE). A decrease of 60% or more from baseline PTH levels at 10 minutes and/or a decrease of 85% or more at 30 minutes predicted the successful removal of all parathyroid glands. CONCLUSIONS: A drop in PTH levels is delayed until 30 minutes after total parathyroidectomy; however, a rapid PTH assay 10 minutes after the removal of the last parathyroid gland is as accurate as an assay performed at 30 minutes postoperatively. Intraoperative PTH monitoring demonstrates relevant decreases in rapid PTH levels after parathyroidectomy that are similar to those previously documented in patients with primary hyperparathyroidism.     

Early prediction of hypocalcemia following total thyroidectomy using combined intact parathyroid hormone and serum calcium measurement

Backgrounds

Concomitant intact parathyroid hormone (iPTH) and serum calcium measurement is deemed to be useful in predicting hypocalcemia after total thyroidectomy. This study aimed to prospectively assess the diagnostic accuracy of combined iPTH and serum calcium measurement in predicting early postoperative hypocalcemia.

Methods

From January 2010 to January 2011, 112 patients underwent total thyroidectomy in our department. A prospective study was carried out to search for factors predicting postoperative hypocalcemia. Serum calcium, phosphorus, and iPTH levels have been measured before operation and at 6, 24, and 48 h postoperatively. Hypocalcemia was defined as a serum calcium level less than 8.0 mg/dL. Sensitivity and specificity of different serum measurements have been calculated using the receiver–operator characteristics curve.

Results

Thirty-three patients (29.5 %) had transient postoperative hypocalcemia. Serum iPTH level showed the highest sensitivity and specificity in predicting hypocalcemia after 6 h (84.8 % and 93.7 %, respectively) for a criterion value ≤12.1 pg/mL. Serum calcium level showed the highest sensitivity and specificity after 24 h (93.9 and 100.0 %, respectively) for a criterion value ≤7.97 mg/dL. Combined cutoffs of 6-h iPTH and 24-h serum calcium showed sensitivity and specificity of 100.0 %.

Conclusions

The combined measurement of 6-h iPTH and 24-h serum calcium are highly predictive of early postoperative hypocalcemia. Patients with serum iPTH and calcium level?≤?criterion value are at major risk for developing hypocalcemia. These results are important in selecting patients eligible for early discharge and those patients who need calcium and vitamin D supplementation.     

No difference in intestinal strontium absorption after oral or IV calcitriol in children with secondary hyperparathyroidism. The European Study Group on Vitamin D in Children with Renal Failure

BACKGROUND: Oral and intravenous calcitriol bolus therapy are both recommended for the treatment of secondary hyperparathyroidism, but it has been claimed that the latter is less likely to induce absorptive hypercalcemia. The present study was undertaken to verify whether intravenous calcitriol actually stimulates intestinal calcium absorption less than oral calcitriol and whether it is superior in suppressing parathyroid hormone (PTH) secretion. METHODS: Twenty children (16 males, age range of 5.1 to 16.9 years, mean creatinine clearance 21.9 +/- 11.5 mL/min/1.73 m2, range of 7.4 to 52.7) with chronic renal failure (CRF) and secondary hyperparathyroidism [median intact PTH (iPTH), 327 pg/mL; range 143 to 1323] received two single calcitriol boli (1.5 mg/m2 body surface area) orally and intravenously using a randomized crossover design. iPTH and 1,25(OH)2D3 levels were measured over 72 hours, and intestinal calcium absorption was measured 24 hours after the calcitriol bolus using stable strontium (Sr) as a surrogate marker. Baseline control values for Sr absorption were obtained in a separate group of children with CRF of similar severity. RESULTS: The peak serum level of 1,25(OH)2D3 and area under the curve baseline to 72 hours (AUC0-72h) were significantly higher after intravenous (IV) calcitriol (AUC0-72h oral, 1399 +/- 979 pg/mL. hour vs. IV 2793 +/- 1102 pg/mL. hour, P < 0.01), but the mean intestinal Sr absorption was not different [SrAUC0-240min during the 4 hours after Sr administration 2867 +/- 1101 FAD% (fraction of the absorbed dose) vs. 3117 +/- 1581 FAD% with oral and IV calcitriol, respectively]. The calcitriol-stimulated Sr absorption was more then 30% higher compared with control values (2165 +/- 176 FAD%). A significant decrease in plasma iPTH was noted 12 hours after the administration of the calcitriol bolus, which was maintained for up to 72 hours without any differences regarding the two routes of administration. CONCLUSIONS: These results demonstrate that under acute conditions, intravenous and oral calcitriol boli equally stimulate calcium absorption and had a similar efficacy in suppressing PTH secretion.     

Intraoperative parathyroid hormone assay for management of patients undergoing total thyroidectomy

BACKGROUND: Rapid parathyroid hormone (PTH) assay has been applied to predict hypocalcemia after thyroidectomy compared with conventional close monitoring of serum calcium levels. We evaluated the reliability of intraoperative intact PTH (ioPTH) assay to predict hypocalcemia after total thyroidectomy and sought to develop an algorithm for the management of postthyroidectomy patients. METHODS: Rapid PTH assays were performed before and after thyroidectomy for 92 new patients receiving total thyroidectomy. Preoperative and postoperative serum calcium and standard PTH levels were serially obtained to 6 months after surgery RESULTS: Postoperative hypocalcemia developed in 34 of 92 patients (37%), who showed significantly lower ioPTH values compared with those of normocalcemic patients (mean 9.2 pg/mL vs 31.3 pg/mL). The ioPTH levels were significantly correlated with standard PTH levels (p < .001, r > 0.62), but not with early serum calcium levels within 8 hours after the operation. Sensitivity and specificity of ioPTH levels of <15.0 pg/mL for the prediction of postoperative hypocalcemia were 85% and 84%, respectively. A value of >15.0 pg/mL and <70% decline in ioPTH after thyroidectomy can reliably identify normocalcemic patients during thyroidectomy or patients requiring close monitoring and early calcium supplement CONCLUSIONS: Rapid ioPTH assay can reliably monitor parathyroid function after thyroidectomy and predict postoperative hypocalcemia. The proposed algorithm based on rapid PTH levels will lead to improved prediction of normocalcemic patients.     

Pretreatment serum FGF-23 levels predict the efficacy of calcitriol therapy in dialysis patients

BACKGROUND: The predictor for the result of calcitriol therapy would be useful in the clinical practice of secondary hyperparathyroidism. Fibroblast growth factor-23 (FGF-23) is a newly found circulating phosphaturic factor. Its circulating level is elevated in uremia. METHODS: Dialysis patients with plasma intact parathyroid hormone (iPTH) levels greater than 300 pg/mL were included in the study. Calcitriol was intravenously injected three times a week. The patients whose plasma iPTH levels dropped below 300 pg/mL within 24 weeks were defined as those who had been successfully treated. A sandwich enzyme-linked immunosorbent assay (ELISA) system that detects human FGF-23 was applied. RESULTS: Sixty-two patients were analyzed. The pretreatment FGF-23 levels were related to the iPTH levels, calcium x phosphate product levels, and history of active vitamin D therapy. The pretreatment FGF-23, iPTH, and calcium levels were lower in the patients who would be successfully treated with calcitriol. A logistic regression study revealed that the pretreatment iPTH and FGF-23 levels significantly affected the therapy results. Analyses using a receiver-operated curve revealed that FGF-23 was the best screening test for identifying patients with future refractory response to calcitriol therapy. The treatment would be successful in 88.2% of those with FGF-23 9860 ng/L and iPTH >591 pg/mL. CONCLUSION: Pretreatment serum FGF-23 levels were a good indicator in predicting the response to calcitriol therapy. The measurement of serum FGF-23 levels, especially in combination with iPTH levels, is a promising laboratory examination for the clinical practice of secondary hyperparathyroidism.     

Unusual cases of chronic intoxication by vitamin D

A 62-year-old man was hospitalized for recent renal colic and neurologic disorders. Routine biochemistry indicated the presence of hypercalcemia (serum total calcium = 15.3 mg/100 mL) and renal failure (serum creatinine = 3.72 mg/100 mL). The patient reported that he had been on treatment with a slow-release multivitamin preparation containing vitamin D and vitamin A, administered by i.m. injection. Plasma 25-OH vitamin D was > 150 ng/mL (normal range 16-74 ng/mL), plasma 1,25-(OH)2 vitamin D was 32.5 pg/mL (normal range 14-60 pg/mL), plasma parathyroid hormone 1.3 pg/mL (normal range 10-65 pg/mL). There were calcifications of left and right iliac artery at abdomen x-ray. Ultrasound and computed tomography of the glutei showed alterations of skeletal muscle and calcifications. Immediate treatment with infusion of isotonic saline, furosemide and prednisone induced rapid control of hypercalcemia and renal failure. Chronic treatment per os was discontinued after six months. The patient reported that the treatment with vitamin D had been prescribed by a physician also to his wife (55-year-old). For the woman, routine biochemistry indicated the presence of hypercalcemia (serum total calcium = 11.3 mg/100 mL) and renal failure (serum creatinine = 1.8 mg/ mL). Plasma 25-OH vitamin D was > 150 ng/mL, plasma 1,25-(OH)2 vitamin D 47.9 pg/mL, plasma parathyroid hormone was 2.5 pg/mL. Hypercalcemia was acutely treated by oral hydration, furosemide, and prednisone. Chronic treatment per os was discontinued after five months.