Persistent elevated serum levels of intact parathyroid hormone after operation for sporadic parathyroid adenoma: evidence of detrimental effects of severe parathyroid disease

Management of surgical diseases of Primary Hyperparathyroidism: indications of the United Italian Society of Endocrine Surgery (SIUEC)

A task force of the United Italian society of Endocrine Surgery (SIUEC) was commissioned to review the position statement on diagnostic, therapeutic and health‑care management protocol in parathyroid surgery published in 2014, at the light of new technologies, recent oncological concepts, and tailored approaches. The objective of this publication was to support surgeons with modern rational protocols of treatment that can be shared by health-care professionals, taking into account important clinical, healthcare and therapeutic aspects, as well as potential sequelae and complications. The task force consists of 12 members of the SIUEC highly trained and experienced in thyroid and parathyroid surgery. The main topics concern diagnostic test and localization studies, mode of admission and waiting time, therapeutic pathway (patient preparation for surgery, surgical treatment, postoperative management, management of major complications), hospital discharge and patient information, outpatient care and follow-up, outpatient initial management of patients with pHPT.

Normocalcemic hyperparathyroidism after successful parathyroidectomy for single parathyroid adenoma: Prevalence, etiological factors, predictive markers, treatment and evolution

BACKGROUND AND OBJECTIVE

Postparathyroidectomy normocalcemic hyperparathyroidism (PPNCHPPT) is a frequent situation for which we have no information in our country. The objective is to know our prevalence of PPNCHPPT, the associated etiological factors, the predictive markers, the treatment administered and the evolution.

PATIENTS AND METHOD

Retrospective observational cross-sectional study on 42 patients. Twelve patients with PPNCHPPT and 30 without PPNCHPPT are compared.

RESULTS

HPPTNCPP prevalence: 28.6%. Etiological factors: vitamin D deficiency: 75%; bone remineralization: 16.7%; renal failure: 16.7%; hypercalciruria: 8.3%. No change in the set point of calcium-mediated parathormone (PTH) secretion was observed, but an increase in the preoperative PTH/albumin-corrected calcium (ACC) ratio was observed. Predictive markers: PTH/ACC ratio (AUC 0.947; sensitivity 100%, specificity 78.9%) and PTH (AUC 0.914; sensitivity 100%, specificity 73.7%) one week postparathyroidectomy.

EVOLUTION

follow-up 30 ± 16.3 months: 50% normalized PTH and 8.3% had recurrence of hyperparathyroidism. Patients with PPNCHPPT less frequently received preoperative treatment with bisphosphonates and postoperative treatment with calcium salts.

CONCLUSIONS

This is the first study in our country that demonstrates a mean prevalence of PPNCHPPT, mainly related to a vitamin D deficiency and a probable resistance to the action of PTH, which can be predicted by the PTH/ACC ratio and PTH a week post-intervention and often evolves normalizing the PTH. We disagree with the etiological effect of hypercalciuria and the change in the PTH/calcemia regulation set point, and we acknowledge the scant treatment administered with calcium salts in the postoperative period.

Analysis of the cause and management of persistent laboratory abnormalities occurring after the surgical treatment of primary hyperparathyroidism

Purpose

The surgical success rate for primary hyperparathyroidism (PHPT) is currently 95%–98%. However, 3%–24% of patients show persistently elevated (Pe) parathyroid hormone (PTH) levels after parathyroidectomy (PTX). This single-center retrospective study aimed to compare the outcomes of patients with normal PTH and PePTH levels after successful PTX and to identify the factors associated with PePTH.

Methods

The normal group, defined as patients with normal serum calcium and PTH levels immediately after PTX, was compared with the PePTH group (patients with normal or low serum calcium and increased serum PTH levels up to 6 months postoperatively) to determine the causes of disease in the PePTH group.

Results

There were no significant differences in age, sex, or preoperative estimated glomerular filtration rate between the normal PTH group (333 of 364, 91.5%) and the PePTH group (31 of 364, 8.5%). However, there were significant differences in preoperative 25-hydroxyvitamin D (17.9 and 11.8 ng/mL, respectively; P = 0.003) and PTH levels (125.5 and 212.4 pg/mL, respectively; P < 0.001) between the 2 groups. Among the 31 cases of the PePTH group, 18 were attributed to vitamin D deficiency.

Conclusion

Preoperative vitamin D deficiency is a predictive factor for PePTH. Therefore, preoperative administration of vitamin D supplements may reduce the probability of postoperative disease persistence. Patients with temporary laboratory abnormalities within 6 months after successful PTX should be monitored, and appropriate vitamin D and calcium supplementation may reduce the effort and cost of various examinations or reoperations.

Persistent Elevation of Parathormone Levels after Surgery for Primary Hyperparathyroidism

BACKGROUND

Persistent elevation of serum parathyroid hormone (PTH) despite normocalcemia have been documented in 8- 40% of patients after parathyroidectomy. We hereby report our experience from different centers across India to determine clinical significance of postoperatively elevated PTH levels and review relevant literature.

METHODS

We conducted a retrospective case series study and reviewed all the patients who underwent surgery for primary hyperparathyroidism (PHPT) from April 2010 to January 2020.

RESULTS

Total of 201 patients was diagnosed as PHPT. Out of available follow-up data of 180 patients, a total of 54 patients (30%) had persistently elevated PTH (PePTH) at 1 month. Patients with PePTH were older with higher preoperative serum calcium, iPTH, alkaline phosphatase and lower serum phosphate and 25-hydroxy vitamin D3 levels. Creatinine clearance was found to be significantly lower in patients with PePTH. Multiple linear regression analysis revealed that preoperative 25-OH D3 concentration, creatinine clearance and iPTH are the factors influencing persistent elevation of PTH levels. Significantly lower serum calcium and higher alkaline phosphatase levels were observed in PePTH patients with preoperative 25-OH D3 levels <20 ng/mL. Thirty patients at 6 months, 24 patients at 1 year, 18 patients at 2 years and 9 patients at 3 years had eucalcemic PTH elevation. Nine out of 126 (7%) patients with normal initial postoperative calcium and iPTH levels developed PePTH, with none culminating into recurrent hyperparathyroidism.

CONCLUSION

Though the pathogenesis of such a phenomenon still remains to be elucidated, a multifactorial mechanism appears to play a role.

Persistently Elevated PTH After Parathyroidectomy at One Year: Experience in a Tertiary Referral Center

CONTEXT/OBJECTIVE

Increased PTH after successful parathyroid surgery represents a clinical conundrum. We aimed to determine the prevalence of persistently elevated PTH (PePTH) postsurgery, along with predisposing factors.

DESIGN

and Setting: Patients ≥ age 18 with parathyroidectomy performed at University of North Carolina Hospitals for primary hyperparathyroidism (PHPT) over a 12-year period were identified from the Carolina Data Warehouse. Clinical and demographic characteristics were collected, transformed, and analyzed.

RESULTS

Five hundred seventy patients met initial criteria for PHPT, and of those 407 had postoperative values. One hundred forty-four had laboratory results within 3 to 18 months post operatively. There was no clinical difference between those with and without long-term laboratory follow-up. Presurgery, patients had average calcium of 11 mg/dL and PTH 125.4 pg/mL. Ninety-seven percent of patients had normalized calcium after surgery, but 30% had PePTH, which can be predicted at 3 months. Patients with PePTH (persistent elevation of PTH) after surgery did not differ from those with normalized PTH in terms of sex, age, body mass index, or excised gland weight; presurgery 25-vitamin D was slightly lower, but not abnormal (26 ± 15 vs 36 ± 11). The presurgical PTH was significantly higher (P < 0.001) in those with PePTH (156.5 pg/mL compared with presurgical level of 102.5 in those whose PTH normalized).

CONCLUSIONS

Nearly one-third of PHPT patients have elevated PTH levels postsurgery in a tertiary hospital setting. At presentation, patients with PePTH tend to have higher PTH relative to calcium levels. Whether PePTH after surgical treatment of PHPT has pathological consequences is unknown.

A retrospective study of elevated post-operative parathormone in primary hyperparathyroid patients

We retrospectively analyzed the relationship between normocalcemic parathormone elevation (NPE) and recurrence of primary hyperparathyroidism (pHPT) after surgery, as well as the risk factors of NPE. Out of 309 patients with pHPT that underwent parathyroidectomy. Six months after surgery, 75 patients exhibited NPE with high preoperative serum levels of alkaline phosphatase, calcium and intact parathyroid hormone (iPTH), postoperative day 1 iPTH, and large parathyroid volume. 15 exhibited NPE at 2 years after surgery with low serum vitamin D levels. Postoperative serum iPTH levels gradually normalized in most patients. Multivariate analysis showed that male patients were at greater risk for postoperative NPE (p<0.05). Only 3 of 309 patients showed recurrence during the follow-up period. NPE may not predict recurrent hyperparathyroidism or incomplete parathyroidectomy for benign parathyroid lesions. Postoperative NPE thus appears to be a response to severe hyperparathyroidism and vitamin D deficiency.

Predictors of recurrence in primary hyperparathyroidism: an analysis of 1386 cases

OBJECTIVE

The purpose of this study was to determine whether the operative approach independently influenced recurrence and to identify perioperative predictors of recurrence.

BACKGROUND

Intraoperative parathyroid hormone (IoPTH) monitoring has enabled surgeons to perform minimally invasive parathyroidectomy (MIP). Yet, the long-term durability of this approach has recently been questioned.

STUDY DESIGN

A retrospective review was performed, and cases of initial neck surgery for nonfamilial primary hyperparathyroidism were selected for analysis. Cases were classified as either open parathyroidectomy (OP) when both sides of the neck were explored or MIP when only one side was explored. Kaplan-Meier estimates were plotted for disease-free survival, and a Cox proportional hazards model was developed to evaluate factors associated with recurrence for both the entire cohort and the MIP subset. Further comparisons were made between those who recurred and those who did not recur.

RESULTS

In the past 10-year period, 1368 parathyroid operations for primary hyperparathyroidism were performed at our institution. A total of 1006 were MIP whereas 380 were OP. There were no differences in recurrence between the MIP and OP groups (2.5% vs 2.1%; P = 0.68), and the operative approach (MIP vs OP) did not independently predict recurrent disease in our multivariate analysis. The percentage decrease in IoPTH was protective against recurrence for both the entire cohort (hazard ratio = 0.96; 95% confidence interval = 0.93-0.99; P = 0.03) and the MIP subset. A higher postoperative PTH also independently predicted disease recurrence.

CONCLUSIONS

Operative approach does not independently predict recurrent hyperparathyroidism. The percentage decrease in IoPTH is one of many adjuncts the surgeon can use to determine which patients are best served by bilateral exploration whereas the postoperative PTH can guide follow-up after parathyroidectomy.

Multifactorial risk profile for bone fractures in primary hyperparathyroidism

Primary hyperparathyroidism (pHPT) is associated with an increased fracture risk, and decreased bone density thus has been considered an indication for surgery. However, many pHPT patients have a multifactorial risk profile for osteoporosis and bone fractures. The aim of the present study was to evaluate variables associated with fracture risk within the group of pHPT patients. A series of 203 consecutive patients operated for pHPT were investigated with bone mineral content and biochemical and clinical risk factors for bone fracture. Seventeen patients (8%) had a history of at least one bone fracture up to 5 years before pHPT surgery. Twenty-six patients (13%) had a history of at least one fracture during the 10-year period prior to surgery. In the univariate analyses corticosteroid treatment, serum levels of alkaline phosphatase, 25-hydroxyvitamin D3, type I collagen telopeptide, and bone mineral content were found to be associated with a history of bone fractures up to 10 years before surgery. Additionally, age and menopausal status were of importance for fractures during the 10-year-period, whereas a history of cardiovascular disease was important for fractures during the 5-year-period prior to surgery. Multivariate analyses showed that serum level of PTH was independently associated with bone fractures during the 5-year period prior to pHPT surgery and further that serum level of 25-hydroxyvitamin D3 was associated with fractures up to 10 years before surgery. In conclusion, serum levels of 25-hydroxyvitamin D3 and PTH were independently associated with a history of bone fractures in pHPT. These variables should be considered when evaluating patients for parathyroid surgery.

Significance of rebounding parathyroid hormone levels during parathyroidectomy

BACKGROUND

Using minimally invasive parathyroidectomy (MIP), most surgeons require a 50% decline in intraoperative parathyroid hormone (IoPTH) to determine cure, but the significance of IoPTH kinetics occurring after this drop remains unknown. The aim of this study was to determine the impact of IoPTH levels that first meet criteria for cure, but then increase again, or rebound, between 10 and 15 min postexcision.

METHODS

We conducted a retrospective review of patients undergoing initial parathyroidectomy for primary hyperparathyroidism at our institution from 2001 to 2011. Rebound IoPTH was defined as an increase in parathyroid hormone ≥5 pg/mL after achieving the 50% drop required for cure. Comparisons were evaluated with the Student t-test, chi-square test, or Fisher exact test where appropriate.

RESULTS

Of the 1386 patients who met selection criteria, 86 (6.2%) patients exhibited rebound IoPTH. The mean magnitude of rebound was 13.8 ± 3.6 pg/mL. Compared with those not displaying rebound, more patients with rebound IoPTH were treated with open parathyroidectomy rather than MIP (10.8% versus 4.5%, P < 0.01). The recurrence rate among those with rebound IoPTH was more than double that of the patients without rebound IoPTH (5.8% versus 2.2%, P = 0.03). Magnitude of rebound, however, did not correlate with recurrence. The rate of persistent disease was not different between those with and without rebound IoPTH. Rebound was a much better indicator of recurrence than patients whose final IoPTH levels were not within the normal range.

CONCLUSIONS

Rebound IoPTH is more common in patients who develop recurrent hyperparathyroidism. Therefore, surgeons should closely monitor patients with rebound IoPTH for disease recurrence.

The impact of vitamin D status and tumor size on the intraoperative parathyroid hormone dynamics in patients with symptomatic primary hyperparathyroidism

PURPOSE

The intraoperative parathyroid hormone (IOPTH) monitoring is a useful adjunct for predicting whether a cure has been obtained during parathyroidectomy. We studied the influence of vitamin D status and parathyroid tumor weight on the IOPTH dynamics for predicting a cure in patients with symptomatic primary hyperparathyroidism.

METHODS

Fifty-nine primary hyperparathyroidism patients with a single adenoma underwent curative surgery. Patients were grouped according to their serum 25-hydroxy vitamin D levels (deficient, insufficient and sufficient) and tumor weights (small, large and giant). The IOPTH results in patient groups were compared, and the percentage of the IOPTH decrease was examined for a correlation with the serum 25-hydroxy vitamin D level and tumor weight.

RESULTS

The sensitivity, specificity and overall accuracy of IOPTH in predicting a cure of hyperparathyroidism were 94.8, 100 and 93.2%, respectively. The percentage decrease in the IOTPH was significantly higher in the vitamin D deficient, compared to the vitamin D sufficient patients (p = 0.012); and in the patients with larger tumors, compared to those with smaller parathyroid tumors (p = 0.02). A statistically significant correlation was found between the percentage decrease in the IOPTH at 10 min post-tumor excision and the serum 25-hydroxy vitamin D level (p = 0.037), but not with the tumor weight (p = 0.208).

CONCLUSIONS

The IOPTH can accurately predict a cure in patients with severe primary hyperparathyroidism. The percentage of decrease in the IOPTH is steeper in patients with lower serum 25-hydroxy vitamin D levels and larger parathyroid tumors.

[Primary hyperparathyroidism. Postoperative normocalcemic hyperparathyrinemia after curative parathyroidectomy]

INTRODUCTION

Normocalcemic hyperparathyrinemia, i.e. elevated parathyroid hormone (PTH) levels after parathyroidectomy in patients with primary hyperparathyroidism (pHPT) may occur in the course of postoperative recovery without the development of persistence or relapse.

MATERIALS, METHODS AND RESULTS

Intraoperative and long-term (7 year) postoperative PTH and calcium levels after curative parathyroidectomy are demonstrated on the basis of a case report of a 62-year-old female patient with severe pHPT and pronounced osseous and renal manifestations. The intraoperative PTH gradient displayed a decrease from 1072 pg/ml to 13 pg/ml (normal range 11-67 pg/ml) followed by an increase of up to 287 pg/ml. The hyperparathyoid values decline to subnormal levels on administration of calcium and vitamin D and increase again after tapering these medications. The inverse calcium/PTH correlation in the course of the 7-year observation period suggests an intact feed-back mechanism. Preoperative PTH screening was performed in 316 consecutive normocalcemic thyroid patients to evaluate the rate of incidental hyperparathyroidism in patients with normal serum calcium levels. Of these patients 31 (9.8%) with normocalcemia (average 2.28 mmol/l, normal range 2.1-2.7 mmol/l) exhibited increased PTH levels averaging 84.2 pg/ml. A parathyroid adenoma was found intraoperatively as the cause for normocalcemic pHPT in only 1 of these 31 patients.

DISCUSSION AND CONCLUSIONS

A review of the literature revealed that late postoperative elevated parathyroid hormone levels after successful pHPT surgery occur in 21.5%. Multiple causes are discussed, e.g. reactive hyperparathyroidism in cases of relative hypocalcemia, hungry bone syndrome, vitamin D deficiency, renal dysfunction and ethnic or lifestyle differences. In mild cases of postoperative hyperparathyrinemia observation of the patient may be sufficient. In cases of reactive hyperparathyroidism due to hypocalcemia, administration of calcium is indicated, in symptomatic patients, additional administration of vitamin D or calcitriol is necessary. Vitamin D deficiency per se needs adequate substitution. In cases of ongoing hyperparathyrinemia an interdisciplinary diagnostic and therapeutic approach is required.

Association of parathyroid adenoma and pregnancy with preeclampsia

OBJECTIVE

Case reports have described associations between calcium metabolism disturbances and primary hyperparathyroidism with preeclampsia, suggesting parathyroid involvement in preeclampsia etiology. This study examines whether parathyroid adenoma, the main cause of hyperparathyroidism, diagnosed and treated before pregnancy is associated with preeclampsia.

DESIGN

We conducted a register-based study to assess the association between parathyroid adenoma and subsequent preeclampsia.

SETTING

Births among Sweden's general population were studied.

POPULATION

The study population included 52 women with a diagnosis of parathyroid adenoma and 519 without, all of whom had a subsequent singleton pregnancy between 1973 and 1997.

METHODS

We performed a conditional logistic regression investigating the association of parathyroid adenoma with subsequent preeclampsia in the first singleton pregnancy with adjustment for potential confounding factors.

MAIN OUTCOME MEASURE

The main outcome was a diagnosis of preeclampsia that does not include women with prior chronic hypertension. To ensure that treatment of parathyroid adenoma was completed before pregnancy, those with a diagnosis of parathyroid adenoma made less than 2 yr before delivery (and the matched comparison women) were excluded.

RESULTS

Statistically, parathyroid adenoma prior to delivery is significantly (P < 0.001) associated with preeclampsia, producing an adjusted odds ratio of 6.89 (95% confidence interval, 2.30, 20.58).

CONCLUSION

A history of parathyroid adenoma should be viewed as a risk for preeclampsia.

Long-term outcome of patients with intraoperative parathyroid level remaining above the normal range during parathyroidectomy

BACKGROUND

Criterion requiring intraoperative parathyroid hormone (IOPTH) drops >50% from the highest, preincision or preexcision level, 10 minutes after the abnormal gland's excision predicts operative success with 98% accuracy. The purpose of this study is to correlate IOPTH dynamics with recurrent hyperparathyroidism (RecHPT) and eucalcemia with high PTH (HPTH).

METHODS

We followed 383 consecutive patients with parathyroidectomy guided by IOPTH monitoring using the above criterion for >6 months. Calcium and PTH levels were measured for 50 months (range, 6-173). Patients were divided in 2 groups: group 1 comprised 302 participants with IOPTH levels that decrease to the normal range (NR), and group 2, with 81 participants who had >50% IOPTH decrease but remained above the normal range. The incidence of RecHPT and eucalcemia with HPTH was evaluated.

RESULTS

RecHPT was found in 2% (8/383) of patients and eucalcemia with HPTH was present in 19% (74/383). In group 1, 17% (52/302) had eucalcemia with HPTH, whereas in group 2, this incidence was 27% (22/81; P = .04). However, only 2% of those (6/302) in group 1 and 2.5% (2/81) in group 2 developed RecHPT (P = .76). Conversely, 70.5% of those (57/81) in group 2 were eucalcemic with normal PTH.

CONCLUSION

Although postoperative eucalcemia with HPTH was significantly higher among patients with IOPTH above the normal range than in patients in group 1, the incidence of RecHPT was not increased. The majority of patients in whom IOPTH did not drop to the normal range continue to be biochemically normal after the operation.

Vitamin D deficiency and primary hyperparathyroidism

Temporally associated with the improvement in vitamin D nutrition in many Western countries in the mid-20th century, there was a change in many characteristics of primary hyperparathyroidism. Osteitis fibrosa cystica became a rare manifestation of what is now frequently an asymptomatic disease. At the same time, in patients with the disease, levels of PTH and parathyroid adenoma weights have fallen dramatically. In view of these observations and others, an association between vitamin D deficiency and severity of primary hyperparathyroidism has been proposed. Data support an association on two distinct levels. First, regardless of the clinical severity of primary hyperparathyroidism, the disease seems to be more severe in those with concomitant vitamin D deficiency. Second, vitamin D deficiency and insufficiency seem to be more prevalent in patients with primary hyperparathyroidism than in geographically matched populations. The association between vitamin D deficiency and primary hyperparathyroidism has clear implications. Co-existing vitamin D deficiency may cause the serum calcium level to fall into the normal range, which can lead to diagnostic uncertainty. With regard to management, preliminary data on vitamin D repletion in patients with mild primary hyperparathyroidism suggest that, in some cases, correction of vitamin D deficiency may be accomplished without worsening the underlying hypercalcemia. Vitamin D-deficient patients undergoing parathyroidectomy are also at increased risk of postoperative hypocalcemia and "hungry bone syndrome," which underscores the importance of preoperative assessment of vitamin D status in all patients with primary hyperparathyroidism.

Oral vitamin D supplementation reduces the incidence of eucalcemic PTH elevation after surgery for primary hyperparathyroidism

BACKGROUND

As many as 43% of patients will have normocalcemic intact parathyroid hormone (PTH) elevation after undergoing curative parathyroidectomy for primary hyperparathyroidism. This phenomenon may be due in part to an absolute or relative deficiency of vitamin D, which is under-recognized in patients with primary hyperparathyroidism.

METHODS

From September 1, 2004, to September 30, 2005, 86 consecutive patients underwent parathyroidectomy for primary sporadic hyperparathyroidism (psHPT). The patients were segregated into 2 groups based on postoperative management. Group 1 was composed of 26 patients who received routine oral calcitriol and calcium carbonate postoperatively. The 60 patients in the second group (group 2) received calcium carbonate postoperatively at the discretion of the primary surgeon.

RESULTS

A total of 85 patients (99%) achieved postoperative cure with sustained reduction in serum calcium. Within 30 days postoperatively, mean serum PTH levels normalized in both groups (41 +/- 31 vs 39 +/- 31 pg/ml; P = .91). However, at 1 to 3 months postoperatively, mean serum calcium levels remained similar (9.5 +/- 0.7 vs 9.3 +/- 0.5 mg/dl; P = .39) whereas mean serum PTH levels in groups 1 and 2 were 43 +/- 25 pg/ml and 67 +/- 45 pg/ml (P = .02), respectively. At 4 to 6 months postoperatively, mean PTH was again higher in group 2 (36 +/- 22 vs 67 +/- 35; P = .03), whereas mean serum calcium levels were normal (9.2 +/- 0.8 vs 9.6 +/- 0.4 mg/dl; P = .18). The incidence of postoperative normocalcemic PTH elevation was significantly higher in group 2 at 1 to 3 months (14% vs 39%; P = .04) and at 7 to 12 months (22% vs 83%; P = .04).

CONCLUSIONS

Vitamin D supplementation following parathyroidectomy for primary hyperparathyroidism reduces the incidence of postoperative eucalcemic PTH elevation.

The role of parathyroid hormone measurements after surgery for primary hyperparathyroidism

BACKGROUND

During parathyroidectomy for primary hyperparathyroidism (pHPT), intraoperative parathyroid hormone (IOPTH) levels are used to confirm removal of all hyperfunctioning parathyroid tissue. The phenomenon of elevated parathyroid hormone (PTH) levels with normocalcemia after curative parathyroidectomy, seen in up to 40% of patients, continues to be an unexpected and unexplained finding. We therefore investigated whether postoperative PTH levels are as reliable as IOPTH levels in predicting cure after surgery for pHPT.

METHODS

We reviewed our prospective database of consecutive patients undergoing surgery for pHPT between December 1999 and November 2004. Curative parathyroidectomy was defined as normocalcemia 6 months or longer postoperatively.

RESULTS

A total of 328 patients who underwent 330 operations for pHPT had IOPTH measurements and serum follow-up calcium levels at 6 months or longer. Surgery was curative in 315 (95.5%) operations. IOPTH levels correctly predicted operative success in 98.2% (positive predictive value [PPV]. Postoperatively, the PPV of a normal PTH level at 1 week, 3 months, and 6 months was 97.1%, 97.3%, and 96.5%, respectively. Of all patients with an elevated postoperative PTH level at 1 week, 3 months, or 6 months, only 13.7%, 14.3%, and 14%, respectively, were not cured.

CONCLUSIONS

Normal postoperative PTH levels reliably predict operative success. However, they do not improve upon results predicted by IOPTH levels. Elevated postoperative PTH levels do not predict operative failure in most patients. We propose that PTH measurements after surgery for pHPT may be misleading, costly, and not indicated in normocalcemic patients.

25-hydroxyvitamin D deficiency is a risk factor for symptoms of postoperative hypocalcemia and secondary hyperparathyroidism after minimally invasive parathyroidectomy

BACKGROUND

Patients with primary hyperparathyroidism who undergo minimally invasive parathyroidectomy (MIP) may have postoperative symptoms of hypocalcemia or secondary hyperparathyroidism. This study sought to identify factors predictive of these events.

METHODS

Between 1998 and 2004, 190 patients with primary hyperparathyroidism underwent MIP with excision of a single adenoma. Age, gender, race, prior head and neck surgery, use of preoperative thyroid hormone or calcium-channel blockers, preoperative levels of calcium, 25-hydroxyvitamin D (25[OH]D) and intact parathyroid hormone (iPTH), the presence of osteopenia or osteoporosis, intraoperative iPTH levels, and adenoma weight were evaluated by univariate analysis as predictors of postoperative symptoms of hypocalcemia and secondary hyperparathyroidism.

RESULTS

None of the following were predictors of postoperative symptoms of hypocalcemia: age, gender, race, prior head and neck surgery, preoperative medications, preoperative calcium and iPTH levels, osteopenia or osteoporosis, intraoperative iPTH levels, or adenoma weight. However, patients with postoperative symptoms of hypocalcemia had significantly lower preoperative 25[OH]D levels (P = .01). Further, higher preoperative iPTH levels (P < .01) and lower preoperative 25[OH]D levels (P = .05) were associated with secondary hyperparathyroidism postoperatively.

CONCLUSIONS

A low preoperative 25[OH]D level is associated with postoperative symptoms of hypocalcemia and secondary hyperparathyroidism in patients undergoing MIP. One might consider instituting empiric calcium supplementation postoperatively in patients with low 25[OH]D levels.

Persistently elevated parathyroid hormone levels after parathyroid surgery

BACKGROUND

Persistent elevation of serum parathyroid hormone (PTH), despite normocalcemia, occurs in 8% to 40% of patients after parathyroidectomy. Explanations have included hypocalcemia owing to vitamin D deficiency or bone remineralization, and persistent hyperparathyroidism.

METHODS

A retrospective chart review of 816 consecutive patients who underwent surgery for primary hyperparathyroidism was conducted.

RESULTS

One hundred fourteen patients (15%) had persistently elevated PTH levels (PPTH). Patients with PPTH had higher preoperative PTH levels than those with normal PTH levels postoperatively. They also had lower postoperative Ca(++) and vitamin D levels. Multiple gland enlargement was identified in fewer patients with PPTH than in those with normal postoperative PTH levels. In patients with PPTH and a postoperative Ca(++) less than 9.6 mg/dL (group I), there was a greater decrease in IOPTH, a higher initial postoperative PTH level, and a lower postoperative vitamin D level than in PPTH patients whose postoperative Ca(++) was > or =9.6 mg/dL (group II). Postoperative Ca(++) and vitamin D levels were also lower in patients whose PPTH did not ultimately resolve. Three patients in group II had recurrent disease.

CONCLUSIONS

Persistent elevation of postoperative serum PTH levels in normocalcemic patients is associated with mild hypocalcemia, probably owing to vitamin D deficiency. In some patients it may also be indicative of mild persistent hyperparathyroidism.

Reelevation of parathyroid hormone level after parathyroidectomy in patients with primary hyperparathyroidism: importance of decreased renal parathyroid hormone sensitivity

BACKGROUND

We hypothesized that impaired peripheral sensitivity to parathyroid hormone (PTH) may play a role in reelevation of PTH after successful operation for primary hyperparathyroidism (pHPT).

METHODS

Factors affecting reelevation of PTH were determined in 90 patients who underwent parathyroidectomy for pHPT. PTH/nephrogenous cyclic adenosine monophosphate ratio, as an index of renal resistance to PTH, was examined in relation to factors shown to influence reelevation of PTH.

RESULTS

Serum PTH levels were elevated above the upper limit of normal in 23 patients (26%) at 1 week and in 39 patients (43%) at 1 month after parathyroidectomy. These 39 normocalcemic patients with elevated serum PTH at 1 month after parathyroidectomy had a higher preoperative serum level of PTH and lower serum phosphate and 25-hydroxyvitamin D (25OHD) concentrations than those with normal PTH (n = 59). Elevated PTH and low 25OHD were shown by multivariate analysis to be significant predictors of reelevation of PTH. Renal resistance to PTH was higher in patients with vitamin D deficiency or renal insufficiency than in patients with normal serum vitamin D concentrations or normal renal function, and it increased according to increases in levels of PTH.

CONCLUSIONS

The mechanism of PTH reelevation in patients with pHPT after successful parathyroidectomy appears to be renal resistance to PTH.

A systematic review of the diagnosis and treatment of primary hyperparathyroidism from 1995 to 2003

OBJECTIVE

To systematically review the current preoperative diagnostic modalities, surgical treatments, and glandular pathologies associated with primary hyperparathyroidism.

STUDY DESIGN

A systematic literature review.

RESULTS

Of the 20,225 cases of primary hyperparathyroidism reported, solitary adenomas (SA), multiple gland hyperplasia disease (MGHD), double adenomas (DA), and parathyroid carcinomas (CAR) occurred in 88.90%, 5.74%, 4.14%, and 0.74% of cases respectively. Tc 99m -sestamibi and ultrasound were 88.44% and 78.55% sensitive, respectively, for SA, 44.46% and 34.86% for MGHD, and 29.95% and 16.20% for DA, respectively. Postoperative normocalcemia was achieved in 96.66%, 95.25%, and 97.69% of patients offered minimally invasive radio-guided parathyroidectomy (MIRP), unilateral, and bilateral neck exploration (BNE). Intraoperative PTH assays (IOPTH) were helpful in approximately 60% of bilateral neck exploration conversion (BNEC) surgeries.

CONCLUSION

The overall prevalence of multiple gland disease (MGD and DA) was lower than often suggested by conventional wisdom. Furthermore, preoperative imaging was less accurate than it is often perceived for accurately imaging MGD. MIRP and UNE were more successful in achieving normocalcemia than is typically quoted. IOPTH was a helpful but not "fool-proof" adjunct in parathyroid exploration surgery.

SIGNIFICANCE

These results support a greater role for the treatment of primary hyperparathyroidism using less invasive approaches. EMB rating: B-3.

Surgical management of primary hyperparathyroidism: the case for giving up quick intraoperative PTH assay in favor of routine PTH measurement the morning after

OBJECTIVE

To analyze the utility of quick intraoperative parathyroid hormone (PTH) measurement in the surgical management of primary hyperparathyroidism.

BACKGROUND DATA

The use of intraoperative PTH monitoring is well established in the surgery of primary hyperparathyroidism. However, some false-negative predictions lead to unnecessary explorations; furthermore, surgeons are becoming increasingly dependent on hormone measurement for intraoperative decisions, which raises concerns about the cost-effectiveness of the method.

METHODS

A retrospective analysis of 268 neck explorations performed for primary hyperparathyroidism using intraoperative PTH monitoring from April 2001 to February 2003 was done. We used the criterion of "biologic recovery" of hyperfunctioning tissue, defined as a more than 50% decrease in PTH level from baseline value at 5 minutes after excision to predict the outcome of successful parathyroidectomy documented by normal postoperative serum calcium level. Additionally, we also sampled PTH at 10 minutes, 30 minutes, and the morning after surgery to compare the predictive value of delayed sampling. Patients were classified according to the prediction being concordant or discordant with the outcome. The data were analyzed using a 2 x 2 table construct for each of the sampling times, therefore providing sequential sensitivity, specificity, positive and negative predictive values, and overall accuracy of the predictions.

RESULTS

Concordance or overall accuracy of prediction (true positives and negatives) was obtained in 229 cases (85.4%), and discordance or failure of prediction (false positives and negatives) was obtained in 34 cases (12.7%) at T5. On analyzing the iPTH prediction at T10, T30, and D1 among the group of 33 false negatives, we found that 28 (10.4%) patients reached the concordance at 30 minutes, while by the first day 32 patients (12.3%) had achieved concordance. Thus, there was a progressive increase in sensitivity and overall accuracy, but more importantly, in the negative predictive value reaching 88.9% on the day after surgery.

CONCLUSIONS

The method of sampling PTH intraoperatively at 5 minutes has a high positive predictive value (99.5%) but a low negative predictive value (19.5%), which can lead to unnecessary explorations and a delay in the operative procedure. The negative predictive value increases substantially at 30 minutes and is best on the day after surgery. We suggest giving up the intraoperative measurement of PTH to adopt the first day postoperative measurement of PTH as a predictor of successful parathyroidectomy.

Recurrent disease after limited parathyroidectomy for sporadic primary hyperparathyroidism

BACKGROUND

Limited parathyroidectomy guided by intraoperative parathyroid hormone (PTH) assay (QPTH) is highly successful (97% to 99%) in predicting postoperative eucalcemia, usually with less extensive dissection when compared with bilateral neck exploration. Because fewer glands are excised when resection is guided by QPTH as opposed to resection guided by gland size, a higher recurrence rate may occur. Recurrence rate after bilateral neck exploration is 0.4% to 5%, but frequency of recurrence after limited parathyroidectomy is unknown. This study reports outcomes of this operative approach in sporadic primary hyperparathyroidism.

STUDY DESIGN

Four-hundred twenty-three patients with sporadic primary hyperparathyroidism undergoing limited parathyroidectomy, followed 6 months or more or considered operative failures, were studied. In most patients, calcium and PTH levels were measured immediately after operation, and then at 2 and 6 months and yearly intervals. Operative failure is defined as hypercalcemia and high PTH within 6 months after operation, and recurrent hyperparathyroidism is hypercalcemia and elevated PTH occurring after a successful parathyroidectomy. Recurrence distributions were estimated using Kaplan-Meier analysis.

RESULTS

The success rate of limited parathyroidectomy is 97% (412/423). Four-hundred six patients were eucalcemic over an average of 34 months (median 27, range 6 to 118 months) of followup and recurrent hyperparathyroidism developed in 6 of 412 (1.5%). Estimated 5 years recurrence-free rate was 97% (95% confidence interval, 91% to 99%). Earliest and latest recurrences were diagnosed at 24 and 83 months, respectively. QPTH results did not predict any recurrence. Overall success rate was achieved, with multiple gland resections performed in only 3% of patients.

CONCLUSIONS

Recurrence rate after limited parathyroidectomy is similar to rates reported after bilateral neck exploration. Parathyroidectomy guided by QPTH is successful not only in resolving hypercalcemia in the short term, but also in providing longterm eucalcemia.

Elevated serum parathyroid hormone concentration in eucalcemic patients after parathyroidectomy for primary hyperparathyroidism and its relationship to vitamin D profile

Elevation of serum parathyroid hormone (PTH) level in eucalcemic patients after parathyroidectomy for primary hyperparathyroidism has been described in up to 40% of patients, but little is known about its etiology or clinical significance. To better understand the cause of this phenomenon, we studied 49 patients without renal dysfunction or osteomalacia who underwent parathyroidectomy for primary hyperparathyroidism. Patients were categorized into 2 groups based on their serum PTH and calcium levels after parathyroidectomy: (1) elevated PTH with eucalcemia (n = 21), (2) normal PTH with eucalcemia (n = 28). Elevation of serum PTH with eucalcemia after parathyroidectomy occurred in 43% of patients. Patients in group 1 had significantly higher preoperative and postoperative mean serum PTH levels and significantly lower postoperative serum levels of 1,25(OH)(2)D(3), 1,25(OH)(2)D(3)/25(OH)D(3) ratio, and 1,25(OH)(2)D(3)/PTH ratio compared with patients in group 2. Serum PTH in group 1 patients normalized as early as 3 months, but remained elevated in some patients for more than 4 years, and was not associated with development of recurrent hypercalcemia. Normalization of serum PTH in group 1 patients was associated with significant increase in 1,25(OH)(2)D(3) and 1,25(OH)(2)D(3)/PTH ratio. Our data suggest that elevation of serum PTH in eucalcemic patients after parathyroidectomy is a frequently reversible state of resistance of the kidneys to PTH-mediated 1-alpha hydroxylation of 25(OH)D(3) and does not signify subsequent recurrence of hyperparathyroidism.

Progress in the operative management of sporadic primary hyperparathyroidism over 34 years

BACKGROUND

Progress in the diagnosis, localization of abnormal parathyroids, and intraoperative management of primary hyperparathyroidism has been observed over the past 34 years. The goal of this study is to report the outcome of patients undergoing 2 different operative approaches in a single institution, showing the evolution of surgical management of sporadic primary hyperparathyroidism (SPHPT).

METHODS

Parathyroidectomy was performed in 890 (827 initial, 63 reoperative) patients with SPHPT using 2 different approaches: traditional bilateral neck exploration (BNE, n = 396) or limited parathyroidectomy guided by parathormone dynamics (LPX, n = 494). Seven hundred eighteen patients (335 BNE, 383 LPX) followed > or = 6 months or identified as operative failures were studied. Operative failure is defined as hypercalcemia and high intact (1-84) parathyroid hormone molecule (iPTH) within 6 months after operation. Successful parathyroidectomy is normocalcemia for 6 months; hypercalcemia and elevated iPTH after this time is recurrent hyperparathyroidism.

RESULTS

There were 20 (6%) of 335 operative failures in the BNE group and 11 (3%) of 383 failures in the LPX group (P = 0.04). The incidence of multiglandular disease (MGD) determined by gland size (10%) versus hormone hypersecretion (3%) was statistically different (P < 0.001). Since most of the recurrences occurred later than 30 months, the incidence of recurrent hyperparathyroidism in patients followed for longer than 2.5 years was 4% (11/287) in the BNE group (average, 11.5 years) and 3% (5/183) in the LPX group (average, 4.2 years).

CONCLUSION

LPX, with its reported advantages of minimal dissection, shorter operative time, and use in ambulatory settings, compares favorably with the traditional BNE. Parathyroidectomy guided by parathormone dynamics has an improved success rate and should be considered as a standard operative approach in SPHPT.

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.

Elevated serum parathormone level after "concise parathyroidectomy" for primary sporadic hyperparathyroidism

BACKGROUND

Cure after parathyroid exploration is traditionally assessed by serum calcium concentration 6 months postoperatively. Postoperative normocalcemic elevation of serum parathormone (PTH) level has been described but is of unclear significance.

METHODS

In a 6-year prospective study of outcomes in 380 patients undergoing initial parathyroidectomy for primary sporadic hyperparathyroidism, we measured intact serum PTH and calcium levels at more than 5 months. Those with normocalcemic high PTH levels were begun on oral calcium + vitamin supplements and monitored.

RESULTS

At more than 5 months postoperatively, normocalcemic elevation in serum PTH level occurred in 28% of patients, was more common after resection of double adenomas (P =.01), and predated the onset of recurrent hypercalcemia in 3 of 3 patients with unrecognized multiglandular disease. Although delayed treatment with calcium and vitamin supplements produced no clear benefit, patients who took such supplements from the date of surgery were much less likely to have an elevated serum PTH level more than 5 months later (P =.0005).

CONCLUSIONS

After successful parathyroid surgery, compensatory normocalcemic elevation in serum PTH level is frequent and may arise from dietary deficiency. Monitored supplemental intake of calcium and vitamin D appears to prevent or to normalize the condition in most patients. Patients with normocalcemic elevation in serum PTH level should receive evaluation for dietary deficiencies as well as follow-up for possible residual disease.

Normocalcemia and persistent elevated serum concentrations of 1-84 parathyroid hormone after operation for sporadic parathyroid adenoma: evidence of increased morbidity from cardiovascular disease

Elevated serum concentrations of 1-84 parathyroid hormone (PTH) after operation for sporadic parathyroid adenoma have been reported in previous studies, years after operation for primary hyperparathyroidism (pHPT). The cause and significance of this finding have not been elucidated. Primary hyperparathyroidism was diagnosed in 195 patients from January 1987 to December 1998. Operation for pHPT was performed in 124 patients. To evaluate long-term effects of elevated serum 1-84 PTH, biochemical variables and pre- and postoperative diseases were investigated from hospital case records. Of the 124 patients operated on, 103 had a solitary adenoma. Among these patients, 60 had normal serum concentrations of 1-84 PTH and calcium postoperatively, 38 patients had follow-up for more than 12 months (range 12-207 months-group A). Persistent elevated serum concentrations of 1-84 PTH and normocalcemia were found in 23 patients. Fourteen patients had follow-up for more than 12 months (range 15-76 months-group B). Two patients had persistent pHPT, and 18 were normocalcemic, but in this retrospective study data on serum 1-84 PTH were not available. No significant differences were found between groups A and B at the time of diagnosis concerning clinical characteristics. More that 12 months after operation for pHPT, the patients in group B, with persistent elevated serum concentrations of 1-84 PTH, had a significantly (c2 = 11, p = 0.005, and power of test 0.66) higher frequency of cardiovascular diseases from ischemic heart disease and hypertension. Persistent elevated serum concentrations of 1-84 PTH after operation for sporadic parathyroid adenoma may be associated with development of cardiovascular disease. This group of patients therefore needs lifelong control and, possibly, medical intervention.

Normocalcemia with elevated parathyroid hormone levels after surgical treatment of primary hyperparathyroidism

BACKGROUND

Thirty percent of patients who undergo successful parathyroidectomy for primary hyperparathyroidism show unexplained elevated postoperative serum parathyroid hormone (PTH) levels despite normocalcemia.

METHODS

PTH levels were measured monthly in 97 patients for 6 months after parathyroidectomy. Renal function, 25-OH-vitamin D levels, serum alkaline phosphatase levels, osteocalcin, and bone densitometry were evaluated before and 6 months after surgery. PTH reactivity to calcium loading was tested at the sixth month.

RESULTS

Thirty patients had elevated PTH levels despite normocalcemia after parathyroidectomy. Before surgery, these 30 patients had higher PTH and creatinine levels, lower vitamin D levels, and more extensive bone involvement than those with normal postoperative PTH levels. In patients with normal renal function and normal vitamin D levels, postoperative PTH values correlated with preoperative PTH levels but not with bone disease.

CONCLUSION

In most cases, elevated PTH levels after surgery is an adaptive reaction to renal dysfunction or vitamin D deficiency. If no adaptive cause can be found, persistent hyperparathyroidism must be suspected.

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.

Late parathyroid function after successful parathyroidectomy guided by intraoperative hormone assay (QPTH) compared with the standard bilateral neck exploration

BACKGROUND

Controversy continues between bilateral neck exploration and limited parathyroidectomy. One approach depends on gland size and histopathologic factors; the other approach limits excision to only hypersecreting glands. Both have excellent early operative success, but late recurrence rates with limited exploration are unknown.

METHODS

Three hundred twenty consecutive patients with primary hyperparathyroidism were followed 6 to 313 months after successful parathyroidectomy. One hundred seventy-six patients had bilateral neck exploration with excision of enlarged glands (group I); 144 patients had glands excised based on hyper-secretion (group II). Calcium and intact parathyroid hormone (iPTH) levels were measured yearly. Parathyroid gland hypersecretion was determined by elevated iPTH levels.

RESULTS

In group I, 1 gland was excised in 160 patients (91%); 19 of 176 patients (11%) had elevated iPTH levels. In group II, 139 patients (97%) had 1 gland excised; 19 of 144 patients (13%) had high iPTH levels. The number of patients with more than 1 gland excised in group I (9%) is 3 times higher than in group II (3%) (P <.05). There was no significant difference in the incidence of recurrent hyperfunctioning glands between the 2 different operative approaches (chi-squared test).

CONCLUSIONS

Late parathyroid gland function was comparable with both approaches. Multiple gland excision based on size alone may lead to excision of normal functioning glands.

Vasoactive and proliferative effects of parathyroid hormone and parathyroid hormone-related peptide on human vascular smooth muscle

BACKGROUND

Hyperparathyroidism is associated with an increased incidence of hypertension and cardiovascular disease. Experiments in rats suggest that this results from desensitization of the normally inhibitory effects of parathyroid hormone-related peptide (PTHrP) on vascular smooth muscle cells (VSMCs) by previous exposure to parathyroid hormone (PTH).

METHODS

Isometric tension in vitro was measured in segments of vessels obtained at neck surgery from six normotensive patients with hyperparathyroidism and 12 eucalcaemic controls undergoing thyroid surgery. Vessels were precontracted with noradrenaline to allow the vasodilatory effects of PTH and PTHrP to be observed. Human VSMCs were cultured in 0.5, 5 and 15 per cent serum with or without PTH (10(-11) to 10(-7) nmol l-(1)) and proliferation was assessed by cell counts after 14 days.

RESULTS

Vasodilatation of arterial segments produced by both PTH 20 nmol l(-1) and PTHrP 100 nmol l(-1) did not differ significantly between control and hyperparathyroidism groups (P > 0.08, Mann-Whitney U test). Vasodilatation by PTHrP was not reduced by preincubation of vessels in vitro with PTH 50 nmol l(-1) for 1 h (P > 0.36, Wilcoxon test). No effects of PTH on serum-induced proliferation of human VSMCs were observed.

CONCLUSION

These data imply that homologous desensitization to PTHrP is not implicated in the pathogenesis of vascular disease in patients with hyperparathyroidism.

Secondary hyperparathyroidism is an expected consequence of parathyroidectomy for primary hyperparathyroidism: a prospective study

BACKGROUND

Parathyroidectomy for primary hyperparathyroidism (PHPT) can cause secondary hyperparathyroidism, with increased serum parathyroid hormone (PTH) and normal or low serum calcium concentrations.

METHODS

A prospective study investigated 78 consecutive patients who underwent exploration for PHPT. Serum intact PTH and total calcium concentrations were measured the evening after operation and ionized Ca++ the following morning. These levels were reassayed 1 week later.

RESULTS

Before operation, the mean PTH level was 138 +/- 15 pg/mL, total calcium concentration was 11.6 +/- 0.1 mg/dL, and ionized Ca++ concentration was 1.44 +/- 0.02 mmol/L. On the night of the operation, the PTH level was 11 +/- 2 pg/mL, and the total calcium concentration was 8.9 +/- 0.1 mg/dL. Fifty-five patients had hypoparathyroidism, with a PTH level less than 10 pg/mL. The day after the operation, the ionized Ca++ level was 1.14 +/- 0.01 mmol/L. One week later, PTH, ionized Ca++, and total serum calcium concentrations returned to normal levels. In 9 patients (12%), PTH levels were increased (98 +/- 16 pg/mL), although ionized Ca++ concentrations were normal (1.18 +/- 0.02 mmol/L), demonstrating secondary hyperparathyroidism. Risk factors for postoperative secondary hyperparathyroidism included older age, symptomatic hyperparathyroidism, higher preoperative PTH and alakaline phosphatase levels, and lower serum phosphorous levels. In 70% of these patients, PTH levels returned to normal in 3 to 12 months.

CONCLUSIONS

Secondary hyperparathyroidism occurs in 12% of patients after surgical treatment of PHPT. It is transient, possibly compensating for relative hypocalcemia.