Metabolic effects of parathyroidectomy in asymptomatic primary hyperparathyroidism.

Effects of parathyroidectomy on parathyroid function and calcium (Ca) metabolism were carefully evaluated in 6 patients with primary hyperparathyroidism without symptoms normally attributed to the disease and in 7 with bone disease or nephrolithiasis. Before parathyroidectomy, both groups of patients demonstrated evidence of the sequelae of parathyroid hormone (PTH) excess, since they presented one or more of the following features: low bone density by 125I-photon absorption, hypercalciuria (urinary Ca greater than 200 mg/day on an intake of 400 mg/day), negative Ca balance (absorbed Ca less than urinary Ca), elevated fasting urinary Ca greater than 0.2 mg/mg creatinine for a night-time sample after a 6-hour fast), and decreased renal function (creatinine clearance of less than 65 ml/min). Following parathyroidectomy, most of these deleterious effects were reversed commensurate with the return of immunoreactive serum PTH, serum Ca, and urinary cyclic AMP toward normal. These quantitative non-invasive techniques may be useful for the initial evaluation and follow-up of patients with asymptomatic primary hyperparathyroidism.     

Urinary cAMP excretion during surgery: an index of successful parathyroidectomy in patients with primary hyperparathyroidism.

Urinary phosphate (Up) and urinary cAMP (UcAMP) excretion were determine in patients undergoing neck exploration for primary hyperparathyroidism in order to evaluate these parameters as indices of successful surgery. UcAMP fell below 1.5 micro mol/g creatinine in all 12 patients in whom single gland removal corrected hypercalcemia and in 0 of 3 patients in whom no parathyroid tissue was found. The mean time to drop below 1.5 was 2.0 +/- 0.8 h (mean /+- SD) from the time of parathyroidectomy. UcAMP fell below 1.5 in only 1 of 6 patients who had multiple enlarged parathyroid glands removed, irrespective of the outcome of surgery. Changes in Up excretion lagged behind UcAMP changes, so that within the time period studied Up fell to varying degrees in only 10 of 15 patients in whom hypercalcemia was corrected. A spurt in UcAMP excretion, possibly reflecting parathyroid hormone release due to manipulation of a parathyroid gland, occurred in 3 patients. The results suggest that an intraoperative fall in UcAMP below 1.5 predicts successful parathyroidectomy and that an intraoperative spurt in UcAMP may provide a clue to the location of abnormal parathyroid tissue.     

Prevalence of glucose intolerance in primary hyperparathyroidism and the benefit of parathyroidectomy

BACKGROUND: Increased prevalence of diabetes mellitus (DM) in primary hyperparathyroidism (PHPT) is established, but not glucose intolerance (GI), nor benefit from parathyroidectomy on GI. We determined these during management of a continuous series of patients with PHPT routinely followed after surgery. PATIENTS AND METHODS: WHO criteria classified 75 g oral glucose tolerance tests (OGTT) in 51/54 consecutively proven PHPT patients, into normal glucose tolerance (NGT), DM, impaired glucose tolerance (IGT) or impaired fasting glucose (IFG); GI was derived by adding those with DM and IGT/IFG. OGTT were repeated after parathyroidectomy (mean follow up 2.4 +/- SD 1.6 years). Paired student t tests were used to compare fasting and 2-h plasma glucose (PG). RESULTS: At presentation 32/54 patients (59%) had NGT, 10 IGT/IFG (19%) and 12 type 2 DM (22%), nine newly diagnosed. Before parathyroidectomy 17/35 patients had NGT (49%), 18 GI (51%), 12 DM (34%) and 6 IGT/IFG (17%). Five out of six patients with IGT/IFG had NGT, one with NGT developed IGT. At completion 23 patients (66%) had NGT, 12 GI (34%), 4 IGT/IFG (11%) and 8 DM (23%). After parathyroidectomy fasting and 2-h. PG fell in 30/34 normocalcaemic patients not on hypoglycaemic agents, 5.6 +/- 1.0 to 5.4 +/- 0.8 mmol/l, 7.2 +/- 3.0 to 6.3 +/- 3.1 mmol/l (p < 0.05, p < 0.01). CONCLUSIONS: 1.At presentation with PHPT, OGTT commonly identifies Type 2 DM and GI.2.After successful parathyroidectomy fasting and 2-h. PG fall significantly (p < 0.05, p < 0.01). DM and IGT/IFG often ameliorates to IGT or NGT, persistently.     

Left ventricular hypertrophy in primary hyperparathyroidism. Effects of successful parathyroidectomy

OBJECTIVE: The association between primary hyperparathyroidism (PHPT) and increased mortality mainly from cardiovascular disease is still debated. The increased mortality previously reported in PHPT was not confirmed in a recent population based study. A high prevalence of left ventricular (LV) hypertrophy was, however, reported in this disease. Although arterial hypertension is regarded as the principal factor, the pathogenesis of LV hypertrophy in PHPT is complex and not completely defined, moreover the effects of successful parathyroidectomy (PTX) are not fully elucidated. The aims of this study were: to ascertain the prevalence of LV hypertrophy in a series of patients with PHPT in comparison to a control population, to seek for relationship between biochemical markers of disease, blood pressure (BP) levels and LV measurements and to evaluate the effects of successful PTX on LV hypertrophy during short-term follow-up. SUBJECTS AND DESIGN: Forty-three patients affected by active PHPT (16 males and 27 females, mean age 60.2 +/- 12.7 years) and 43 controls age- and sex-matched with the same prevalence of arterial hypertension were studied in a case-control analysis. Each subject underwent a M- and 2D mode echocardiographic evaluation and repeated BP measurement. In 21 PHPT submitted to surgery the echocardiographic measurement was repeated 6 months after successful PTX. MEASUREMENTS: Serum concentrations of parathyroid hormone (PTH), total-(Ca) and ionized calcium (iCa), phosphate, creatinine, total alkaline phosphatase (TALP) were measured in patients with PHPT at diagnosis and six months after PTX in the subgroup operated on; BP values were measured in three different occasion; mono and 2D echocardiographic evaluation was performed in control subjects and patients with PHPT either before and after PTX. RESULTS: LV hypertrophy, measured by LV mass index (LVMI), was present in 28/43 PHPT patients (65.1%) and in 15/43 (34.8%) controls, P < 0.05; among hypertensive subjects, 21/21 (100%) PHPT patients and 13/21 (61.9%) controls P < 0.05 were hypertrophic while among normotensive subjects, these figures were 7/22 (31.8%) for PHPT patients and 2/22 (9%) for controls, P = 0.67. At multiple regression analysis in a model including biochemical parameters and BP values, serum PTH levels were associated with LVMI values as the strongest predicting variable (0.46, P < 0.02). Six months after PTX, LVMI decreased (137.8 +/- 37.3 vs 113.0 +/- 28.5, P < 0.05) without changes in mean BP values and ratio of hypertensive patients. CONCLUSION: The present data confirm the high prevalence of LV hypertrophy in primary hyperparathyroidism also in a group of patients with an asymptomatic clinical presentation. The correlation between PTH values and left ventricular mass index suggests an action of the hormone in the pathogenesis of LV hypertrophy confirmed also by the decrease of left ventricular mass index after the reduction of PTH levels. The reversal of left ventricular mass index after parathyroidectomy could affect mortality in primary hyperparathyroidism. An echocardiographic study could be suggested in the clinical work-up of primary hyperparathyroidism in order to evaluate heart involvement and the response to successful parathyroidectomy.     

Left ventricular structure and function in primary hyperparathyroidism before and after parathyroidectomy

OBJECTIVE: Our aim was to study the effect of primary hyperparathyroidism (PHPT) and parathyroidectomy (PTX) on left ventricular (LV) wall thicknesses and systolic and diastolic function. METHODS: Fifteen patients with untreated PHPT were evaluated by applying Doppler and digitized M-mode echocardiography before and 2-3 months after PTX. Fifteen age- and sex-matched healthy controls were also examined echocardiographically. RESULTS: Prior to PTX, interventricular septal thickness (IVST), LV mass (LVM), aortic root dimension and left atrium dimension were greater and LV fractional shortening was slightly decreased in patients as compared to controls. Significantly increased LV peak late diastolic velocity (A(max)) and isovolumic relaxation time, and a slightly decreased ratio of peak early to peak late diastolic velocities (E/A(max)) in the patients indicated impairment of LV diastolic function in hyperparathyroidism. PTX reduced serum total Ca from 2. 79 +/- 0.13 to 2.39 +/- 0.09 mmol/l (p < 0.001) and tended to reduce IVST [10.6 +/- 2.1 vs. 10.4 +/- 2.0 mm; not significant (n.s.)], LV posterior wall thickness (9.6 +/- 2.0 vs. 9.2 +/- 1.0 mm, n.s.) and LVM (250 +/- 102 vs. 213 +/- 42 g; n.s.). Before PTX, there was a significant correlation between serum total Ca and LVM (r = 0.63, p < 0.05), and the PTX-induced change in serum total calcium correlated with the change in LVM (r = 0.59, p < 0.05). PTX induced no significant changes in LV systolic or diastolic function during the follow-up of 2-3 months. CONCLUSIONS: The present findings indicate that PHPT induces LV hypertrophy, slight impairment of LV systolic function and significant impairment of LV diastolic function, which are not substantially improved after TX and 2-3 months of normocalcemia.     

Marked improvement of psychiatric symptoms after parathyroidectomy in elderly primary hyperparathyroidism

Psychosomatic symptoms in primary hyperparathyroidism (PHPT) are various and include such conditions as obsessive-compulsive disorder, depression, anxiety, and paranoia. In the elderly the clinical features of the disease are often non-specific and difficult to diagnose. To quantify subjective symptoms of patients with hyperparathyroidism in the elderly, we determined whether these clinical manifestations resolved after surgical parathyroidectomy (PTX) in three PHPT patients over eighty years old. They were diagnosed with hypercalcemia, hypophosphatemia, high PTH concentrations, and osteoporosis. A single parathyroid adenoma was confirmed in each patient by Tc-MIBI scintigram, neck ultrasonography and computed tomographic scanning. PTX was performed in these three patients. Assessments of psychologic symptoms, using the Hamilton Rating Scale for Depression (HAM-D), serum calcium, and intact PTH were obtained before and after PTX. Mean weight of the resected adenomas was 438 +/- 138 mg (mean +/- SD). After PTX, serum calcium decreased from 11.1 +/- 0.5 to 9.2 +/- 0.5 mg/dl and intact PTH from 160.0 +/- 25.2 to 45.3 +/- 22.2 pg/ml. Total HAM-D scores in each patient decreased from 45 to 9, 17 to 1 and 15 to 5, respectively. Especially, there were marked improvements in depressive mood, psychomotor inhibition, anxiety and somatic symptoms after PTX. The quality of life in those patients was also improved by PTX. We propose here that PTX in elderly PHPT patients with psychiatric symptoms should be considered instead of oral administration, such as anti-depressants or bisphosphonates.     

Spectrum of renal dysfunction after curative parathyroidectomy in symptomatic primary hyperparathyroidism

ObjectiveThe long-term renal consequences of curative parathyroidectomy (PTX) in symptomatic primary hyperparathyroidism (sPHPT) are not well characterized. We aimed to assess renal glomerular and tubular functions in an sPHPT cohort at ≥ 1 year's follow-up.DesignRetrospective-prospective study.MethodssPHPT patients with preoperative eGFR ≥ 60 mL/min/1.73m² and in remission (normocalcemic) for ≥ 1 year after PTX underwent clinical and biochemical assessment (calcium profile, renal parameters). Ammonium chloride and bicarbonate loading tests were performed in patients with renal tubular dysfunction (RTD).ResultsForty-eight patients (31 females) with median plasma PTH 1,029 (338–1604) pg/mL and mean eGFR 109.2 ± 26.0 mL/min/1.73m² at diagnosis were evaluated at 5.62 ± 3.66 years after curative PTX. At follow-up, eGFR was < 60 mL/min/m² in 5 patients (10.4%). Patients with > 10% drop in eGFR (n = 31) had significantly higher pre-PTX plasma PTH (1,137 vs. 687 pg/mL), and longer time to post-PTX evaluation (6.8 vs. 3.4 years). RTD was seen in 11 patients (22.9%): urinary low molecular weight proteinuria (14.6%), distal renal tubular acidosis (12.5%), hypophosphatemia (8.3%), and hypokalemia (8.3%); RTD was associated with significantly lower post-PTX eGFR (72.7 vs. 95.4 mL/min/m²). Five of the 7 RTD patients undergoing loading test had impaired urinary acidification, whereas none had impaired bicarbonate resorption.ConclusionsReduction in eGFR and subclinical RTD were prevalent at long-term follow-up in the present Asian-Indian cohort with cured sPHPT. Further studies are warranted to understand the clinical implications of these various renal abnormalities.     

Positive effect of parathyroidectomy on bone mineral density in mild asymptomatic primary hyperparathyroidism

OBJECTIVES: Patients with mild primary hyperparathyroidism (pHPT) often appear asymptomatic, and have previously been regarded as not requiring treatment. However, increased cardiovascular morbidity and dyslipidaemia have also been recognized in mild pHPT, which also seem to be normalized after parathyroidectomy. The present study explores whether postmenopausal women with mild pHPT have decreased bone mineral density (BMD) compared with age-matched healthy controls, and the effects on BMD of parathyroidectomy. DESIGN, SUBJECTS AND INTERVENTION: A population-based health screening of 5202 postmenopausal women identified 87 overtly asymptomatic patients with mild pHPT as well as age-matched healthy controls. A 5-year follow-up included 49 cases who had undergone parathyroidectomy. BMD was measured with DXA at the femoral neck, the lumbar spine and the total body. RESULTS: At study entry, BMD was 5-6% lower in the lumbar spine (L2-L4) and femoral neck in cases compared with matched controls. After the 5-year follow-up, BMD increased in L2-L4 by 2.9% (P = 0.002) in the parathyroidectomized cases and remained stable in the femoral neck. However, femoral neck BMD increased 4.1% (P = 0.013) for cases <67 years old (50% of the cohort). CONCLUSION: In accordance with recent NIH guidelines for pHPT treatment, the level of BMD per se in the investigated group of patients justifies parathyroidectomy in almost half of the cases with mild pHPT. Surgery could be expected to increase BMD in L2-L4 to the level of the controls, to increase femoral neck BMD in patients <67 years of age and to preserve femoral neck BMD in the elderly population.     

Impact of parathyroidectomy on cardiovascular risk in primary hyperparathyroidism: A narrative review

AimsPrimary hyperparathyroidism (PHPT), one of the most frequent endocrine disorders, is not only associated with bone and kidney disorders but also with increased cardiovascular risk. This cardiovascular risk is not part of the indication for surgery owing to discordant evidence of the effects of parathyroidectomy (PTX), especially in mild PHPT which is the most common presentation of PHPT. This literature review focuses on the effects of PTX on the cardiovascular risk in PHPT. The MEDLINE database was searched via the PubMed interface, selecting relevant articles published after 1990 in English.Data synthesisIn the most recent series, PTX appeared to have a positive impact on cardiovascular morbidity and mortality. Surgery improves arterial hypertension, markers of glucose homeostasis, vascular and cardiac remodeling and electrocardiographic impairments due to classical PHPT. However, the results of surgery on mild PHPT are conflicting.ConclusionsPTX seems to improve cardiovascular risk in patients presenting the classical form of PHPT. This improvement is correlated with preoperative serum calcium and/or PTH level, depending on the cardiovascular risk factor. However, many aspects of this improvement are not fully understood. Future studies should assess the effects of PTX on nocturnal hypertension, cardiac morphology and functions. The results for mild PHPT are conflicting owing to the limited size of the cohorts included in studies and the lack of randomized trials. Surgery is not currently recommended for patients presenting mild PHPT based on the cardiovascular risk and more studies are needed to better understand the interest of PTX on cardiovascular outcomes.     

Importance of increased urinary calcium excretion in the development of secondary hyperparathyroidism of patients under glucocorticoid therapy

Parathyroid function and calcium metabolism were studied in 44 patients under glucocorticoid therapy (steroid group) and in 25 control subjects. Nephrogenous cAMP and serum immunoreactive parathyroid hormone levels in the steroid group were significantly higher than those in control subjects (p less than 0.001). Nephrogenous cAMP in the steroid group correlated positively with prednisolone dosage (r = 0.424, p less than 0.01), and most patients who showed obvious elevations of nephrogenous cAMP had received over 10 mg/day of prednisolone for at least 2 mo. Fasting urinary calcium in the steroid group [166.1 +/- 78.5 (+/- SD) mg/g creatinine] was about 2 times greater than that in control subjects (74.1 +/- 35.6) (p less than 0.001). Fasting urinary calcium in control subjects correlated negatively with nephrogenous cAMP (r = -0.486, p less than 0.02). In contrast, these values in steroid group showed significant positive correlation (r = 0.631, p less than 0.001), suggesting that increased urinary calcium excretion is an important factor in the development of secondary hyperparathyroidism. Elevated nephrogenous cAMP and serum immunoreactive parathyroid hormone levels decreased after the administration of trichlormethiazide and/or 1 alpha hydroxy-vitamin D3. We conclude that increased urinary calcium excretion plays an important role in the development of secondary hyperparathyroidism in patients under glucocorticoid therapy and that the administration of thiazide and/or vitamin D could improve the secondary hyperparathyroidism caused by glucocorticoid therapy.     

Cortical bone mineral content in primary hyperparathyroidism. Changes after parathyroidectomy

The bone mineral content (BMC) of 35 patients with primary hyperparathyroidism (PHPT) was measured at the mid radius (95% cortical bone) by photon absorptiometry of a 241Am source. The majority of the patients had an overt disease of moderate to severe degree. Average serum calcium of the group was 12.3 mg/100 ml (range 10.6 to 18.0 mg/100 ml). The percentage of normality of the BMC was (Av +/- 1 SD) 75.1 +/- 13.0% for the whole group. The average increment of BMC in 14 patients 9 to 26 months after parathyroidectomy was 9.9%, with a wide dispersion. However a highly significant negative correlation (r: 0.83; P less than 0.01) was found between the initial bone mass and the percentage increment per month after surgery. No further gain was observed 2 years after parathyroidectomy except in one patient with an extremely severe bone loss. In spite of the gain obtained after surgery the bone mass remained markedly diminished in most patients showing that the cortical bone loss caused by PHPT is mainly irreversible.     

Effect of parathyroidectomy on serum 1 alpha,25-dihydroxyvitamin D and intestinal calcium absorption in primary hyperparathyroidism.

Serum concentration of 1 alpha,25-dihydroxyvitamin D [1,25(OH)2D] and intestinal absorption were measured before and after parathyroidectomy in 11 patients with primary hyperparathyroidism. Serum 1,25(OH)2D was high preoperatively (P less than 0.001) and normal postoperatively. Ca absorption was elevated preoperatively (P less than 0.001) and decreased significantly after parathyroidectomy (P less than 0.001). However, 5 of 11 patients had a persistent hyperabsorption of Ca postoperatively, despite normal serum 1,25(OH)2D. The results suggest that factors other than 1,25(OH)2D contribute to the maintenance of high intestinal Ca absorption in hyperparathyroid patients in the postoperative state.     

Prediction of bone mass change after parathyroidectomy in patients with primary hyperparathyroidism

A major challenge in the management of primary hyperparathyroidism (pHPT) is the decision regarding which patients should undergo parathyroidectomy (PTX), although the Consensus Development Conference of the NIH has proposed guidelines for the indication of surgery. In the present study, changes in bone mineral density (BMD) after PTX were compared between pHPT patients who did and did not meet the NIH criteria, and we further tried to predict the BMD change after PTX from preoperative parameters. The subjects were 44 pHPT patients (30 women and 14 men) who had had successful PTX. Lumbar and radial BMD were measured before and 1 yr after PTX by dual energy x-ray absorptiometry and single photon absorptiometry, respectively. Average annual percent increases in lumbar and radial BMD after PTX were 12.2 +/- 1.4% and 11.6 +/- 1.6% (mean +/- SEM), respectively, and those net increases were 0.0803 +/- 0.0008 and 0.0484 +/- 0.0006 g/cm2, respectively. There were no significant differences in percent or net changes in either radial or lumbar BMD after PTX between the groups divided according to each of the NIH criteria, such as age (> or =50 and <50 yr), serum calcium level (> or =12 and <12 mg/dL) or the existence of urinary stones (presence and absence). On the other hand, when the subjects were divided on the basis of radial BMD (above and below a z-score of -2), the annual percent and net increases in lumbar BMD and percent increase in radial BMD after PTX were significantly higher in the group with the lower z-score. Next, patients were divided into two groups with and without the indication of PTX based on NIH guidelines. Twenty-nine patients had the surgical indication by meeting one or more of these criteria and 15 patients had no indication without meeting any of the criteria. There were no significant differences between the two groups in annual percent or net changes in radial or lumbar BMD after PTX. A stepwise multiple regression analysis revealed that serum alkaline phosphatase level and the severity of cortical bone mass reduction were the best predictors of both percentage and net changes in lumbar BMD, with high determination coefficients (r2 > 0.7). In conclusion, a considerable increase in BMD could be obtained after PTX even in patients without surgical indication from the NIH. Alkaline phosphatase and the severity of cortical bone mass reduction are clinically useful for predicting the changes in lumbar BMD after PTX. The present findings provide a useful clue for the indication of surgery in pHPT.     

Forearm bone density in primary hyperparathyroidism: long-term follow-up with and without parathyroidectomy

OBJECTIVE: The long-term effects of primary hyperparathyroidism (PHPT), whether treated or untreated, on cortical bone are unclear, but the balance of evidence suggests that fracture risk is modestly increased in this patient group. We therefore compared changes in forearm cortical bone mineral density (BMD), at the site most relevant for PTH-mediated bone loss, in two groups of patients with PHPT; one with and one without surgery. DESIGN AND PATIENTS: We followed the course of forearm bone mineral/bone width (BM/BW, g/cm2) measured by single-energy photon absorptiometry at the standard proximal site, and Z-scores (deviations from the mean value expected for age, sex and race, calculated from a large local reference population) in 108 patients who underwent successful surgery (mean duration 47 months, range 12-120 months) and 108 who remained unoperated (mean duration 52 months, range 12-132 months). Criteria for recommending surgery had been formulated in 1975 and were generally similar to those of the NIH consensus conference published in 1991. At the time of diagnosis the Z-score was significantly reduced in both groups, indicating an earlier period of accelerated cortical bone loss. RESULTS: In the entire operated population there was no difference between the initial and final BM/BW. As the age-expected mean value declined, the Z-score became significantly less negative, and if the rate of change remained constant the values would have reached zero, indicating recovery of all bone lost as a result of the disease, after about 20 years. In the unoperated patients BM/BW fell significantly but there was no change in Z-score, indicating that the rate of bone loss was the same as expected for normal ageing. CONCLUSIONS: It is reasonable to assume that cessation of further bone loss consequent on successful parathyroid surgery would eventually lead to abatement of the excess fracture risk, but the benefit to individual patients will depend mainly on their remaining life expectancy.