Anesthetic considerations in hyperparathyroid crisis: A case report.

INTRODUCTION: Hyperparathyroid crisis is a rare and potentially life-threatening complication of severe calcium intoxication. Parathyroidectomy is the only curative method for hyperparathyroid crisis. Several case reports and case series have been published on the medical and surgical treatments for hyperparathyroid crisis, however, few reports have focused on the associated perioperative anesthetic management. PATIENT CONCERNS: A 48-year-old Chinese woman presented with a 2-week history of nausea and vomiting and complained of mental status alteration including confusion and agitation in the 24 hours prior to her admission. She denied any history of past illness. Laboratory tests showed severe hypercalcemia crisis with a serum calcium level of 5.21 mmol/L and a serum intact parathyroid hormone level of > 5000 pg/mL. DIAGNOSIS: The diagnosis was hyperparathyroid crisis, acute kidney injury, acute liver injury, rhabdomyolysis, infection, and shock. INTERVENTIONS: She underwent initial management with aggressive intravenous fluid resuscitation, loop diuretic treatment, vitamin D supplement, intravenous bisphosphonates, and calcitonin therapy. However, her condition worsened, and she was transferred to the operating theater for a parathyroidectomy under general anesthesia. She was under general anesthesia and monitored with electrocardiogram, pulse oxygen saturation, continuous arterial blood pressure, central venous pressure and nasopharyngeal temperature. Cardiac output and stroke volume variation were monitored from the FloTrac system. After liberal fluid rehydration, circulatory support, cooling treatment and calcium supplement after tumor removal, her unstable vital signs gradually improved. OUTCOMES: After meticulous anesthetic management by the anesthesiologist and complete tumor resection by the surgeon, she survived this fatal disease. The patients was discharged on postoperative day 37 without any sequelae. LESSONS: Patients with hyperparathyroid crisis should undergo a thorough preoperative evaluation. Difficult airway, fluid depletion, multiple organ dysfunction, hypercoagulability, and concomitant diseases are the primary challenges in anesthetic management. After tumor removal, the serum calcium level should be monitored closely and calcium should be supplemented in a timely manner to prevent serious complications.

Successful Use of Denosumab for Life-Threatening Hypercalcemia in a Pediatric Patient with Primary Hyperparathyroidism.

INTRODUCTION: Primary hyperparathyroidism (PHPT) is rare and usually symptomatic in children. There is no approved medication to lower serum calcium levels in this patient group. Denosumab is used in adult patients with osteoporosis and hyperparathyroidism. To our knowledge, only 1 case of denosumab treatment in a child with severe PHPT has been reported to date. CASE PRESENTATION: A 16-year-old female was referred to our clinic with symptoms including pathologic fractures, nausea, emesis, and progressive weight loss. At admission, her serum total calcium was 4.17 mmol/L (reference range 2.15-2.55), parathyroid hormone 2,151 pg/mL (15-65), and phosphate 1.07 mmol/L (1.45-1.78). Due to potentially life-threatening hypercalcemia, denosumab 60 mg subcutaneously was administered after obtaining informed consent. Serum calcium levels were reduced within 12 h of injection and the patient's condition rapidly improved, which allowed genetic testing to be done prior to surgery. A heterozygous mutation in the CDC73 gene was revealed, and a parathyroidectomy was performed on day 22 after denosumab administration. Morphological examination revealed solitary parathyroid adenoma. After surgery, hypocalcemia developed requiring high doses of alfacalcidol and calcium supplements. CONCLUSION: Our case supports the previous observations in adults that denosumab can be safely and effectively used as a preoperative treatment in patients with PHPT and severe hypercalcemia and shows that it may be used in pediatric patients.

Moderators of the Association Between Serum Parathyroid Hormone and Metabolic Syndrome in Participants with Elevated Parathyroid Hormone: NHANES 2003-2006.

This cross-sectional study extracted data of 392 NHANES participants with elevated serum parathyroid hormone (PTH) concentrations from 2 cycles of the US National Health and Nutrition Examination Survey (NHANES) 2003-2006 and evaluated the association between serum (PTH) concentration and metabolic syndrome (MetS) to identify dietary and lifestyle factors that may modify that association. The primary outcome was MetS severity scores. Results of univariate linear regression analyses revealed that serum PTH concentrations correlated positively and significantly with MetS severity scores (ß=0.399, p=0.030). After adjusting for gender, age, race, and alcohol consumption, results of multivariate analysis revealed that increased serum PTH concentration correlated significantly with higher MetS severity scores (ß=0.413, p=0.045) in participants with moderate physical activity over the past 30 days. Serum PTH concentration also correlated significantly with higher MetS severity scores in participants with serum 25-hydroxyvitamin D deficiency (ß=0.456 and p=0.014), those without vitamin D supplementation (ß=0.524, p=0.028) and with higher protein intake (ß=0.586 and p=0.030). In conclusion, increased serum PTH concentration is associated with higher MetS severity scores in participants with elevated serum PTH at baseline. The association between PTH concentration and MetS severity is moderated by participants' physical activity levels, status of serum vitamin D, vitamin D supplementation, and daily protein intake.

Correlation Between the Parathyroid Glands Size and Parathormones Value in Patients with Hyperparathyroidism.

INTRODUCTION: Hyperparathyroidism is a common endocrine disorder with potential complications of bone, renal, neurocognitive and cardiovascular system. AIM: To determine the correlation between the size of parathyroid glands and parathormone values in the patients with hyperparathyroidism. METHODS: We analyzed a retrospective-prospective database of 79 consecutive patients who underwent parathyroidectomy for hyperparathyroidism at our institution between January 2011 and February 2018. The values of parathormone, calcium and phosphorus were determined in all patients before and after surgery. Ultrasonography were performed before surgery. Imaging results were confirmed by pathology. We analyzed the correlation between the sizes parathyroid glands obtained trough ultrasonography and pathology with parathormone values. RESULTS: The median age of the patients were 51 age (range 20-73) and 67,1% of the patients were female. Our study demonstrated that between actual glands sizes (volumes), expresses in millimeters, measured on pathohistological analysis and ultrasound examination and size value of parathormone its increased value does not affect the size of the gland. We investigate the correlation between the size of glands measured according to the pathohistological finding and the value of parathormone we obtained the correlation results close to the statistical features. The correlation value of parathormone and glands sizes according to the pathohistological finding measured trough the determined assessment scale we determined the statistically important of medium value. CONCLUSION: One of the important factors for parathyroidectomy is the value of parathormone. Serum parathormone level might be predictable by a total size of parathyroid glands and could be an effective the predictor of gland localisation.

Parathyroidectomy in Persistent Post-transplantation Hyperparathyroidism - Single-center Experience.

BACKGROUND: Hyperparathyroidism is a common complication in chronic kidney disease and might persist in up to 25% of patients after transplantation. In this setting, vitamin D analogues further aggravate persistent hypercalcemia and cinacalcet has not been approved for these patients, some of whom will require parathyroidectomy to correct post-transplantation hyperparathyroidism. OBJECTIVES: In this single-center, retrospective study we aimed to analyze the long-term effect of parathyroidectomy on calcium, phosphorus, and parathyroid hormone (PTH) levels and its effect on allograft function in kidney transplantation patients submitted to parathyroidectomy. PATIENTS AND METHODS: Fifteen patients underwent parathyroidectomy between January 2005 and January 2015; median age 54 years old; 8 (53.3%) were receiving cinacalcet at the time of surgery. Pre-parathyroidectomy median values of intact PTH, calcium, and phosphorus were, respectively, 262 pg/mL, 10.8 mg/dL, and 2.4 mg/dL. Surgery consisted of uniglandular parathyroidectomy in 5 (33.3%) patients, biglandular in 4 (26.7%), and subtotal in 6 (40%). There was no surgery-related mortality. RESULTS: Compared with baseline, there was a decrease of PTH (262 pg/mL vs. 106 pg/mL, P = .001), calcium, and phosphorus levels (10.8 mg/dL vs. 10.4 mg/dL, P = .3; 2.4 vs. 2.9 mg/dL, P = .05) 1 year after surgery; with normalization of serum calcium at the end of follow-up (10.8 mg/dL vs. 9.4 mg/dL, P = .04). A decrease in estimated glomerular filtration rate occurred 1 month post-surgery (62.7 mL/m vs. 49.7 mL/m, P = .006) but returned to baseline 1 year after surgery (62.7 mL/m vs. 60.8 mL/m, P = .73). CONCLUSION: Parathyroidectomy appears to be a safe procedure and should be considered in kidney transplantation patients with persistent post-transplantation hyperparathyroidism. Although there was an acute estimated glomerular filtration rate decrease, we observed no long-term deterioration in allograft function.

Changes in Serum Concentrations of Fibroblast Growth Factor 23 and Soluble Klotho in Hemodialysis Patients after Total Parathyroidectomy.

Background. We examined the changes in circulating fibroblast growth factor 23 (FGF23) and Klotho concentrations in hemodialysis patients after parathyroidectomy (PTX). Methods. We enrolled a cohort of hemodialysis patients who received PTX. Postoperatively, patients received calcium supplements and/or vitamin D analogue (calcitriol) to maintain serum calcium within 7.0-8.0 mg/dL. Information on clinical parameters including bone-mineral metabolic variables was collected pre-PTX and on days 5 and 90 after PTX. Concomitantly, serum full-length FGF23 and α-Klotho levels were measured. The relationship between FGF23 and clinical parameters was analyzed by single linear regression. Results. Forty-six participants (33 women; 13 men) were enrolled in the study. Their mean age was 56.49 years. Serum FGF23 and α-Klotho concentrations were elevated on days 5 and 90 after PTX compared to baseline (p > 0.05). Serum FGF23 concentrations negatively correlated with serum calcium concentrations pre-PTX (Beta -0.31; R2 0.0949; p = 0.040), day 5 post-PTX (Beta -0.31; R2 0.0982; p = 0.036), and day 90 post-PTX (Beta -0.39; R2 0.1528; p = 0.008). Conclusions. There was no change in circulating FGF23 and Klotho concentrations after PTX in hemodialysis patients given postoperative calcium supplements and/or vitamin D analogue. Serum FGF23 concentrations pre-PTX and at days 5 and 90 after PTX were inversely related to serum calcium concentrations.

Vitamin D (25(OH)D) in patients with chronic kidney disease stages 2-5.

OBJECTIVE: To establish the impact the chronic kidney disease stage has in the native vitamin D levels in patients not undergoing dialysis treatment. METHODS: A study performed in Manizales, Colombia, a city located 2,200 meters above sea level, without important stational variations. Patients with 18 years of age or more, with chronic kidney disease stages 2 to 5 and not undergoing dialysis treatment were recruited for this study. Demographic and anthropometric variations were evaluated as well as solar exposure, CKD etiology and laboratory variables related to bone and mineral diseases. For each CKD clinical stage, correlations were evaluated for vitamin D levels, laboratory results for bone and mineral diseases, solar exposure and ethnicity. RESULTS: Three hundred thirty-three patients were evaluated with a median age of 71 years, most of them mestizo (71%), 173 were women. The main CKD etiology was hypertensive nephropathy (32.2%). 21.1% of patients had normal vitamin D levels, 70.1% were within insufficient range and 8.8% were in deficit. A negative correlation was found between the levels of vitamin 25 (OH) D and the values for: creatinine, phosphorous, calcium x phosphorous product, PTH, 24 hours urine protein and BMI. A positive relationship was found for calcium and albumin. Positive significant statistical correlation was found for vitamin 25(OH) D levels and solar exposure for stages 3b and 4 of CKD. CONCLUSIONS: It is common to find low levels of vitamin 25(OH) D in patients with CKD; these can contribute to the appearance of secondary hyperparathyroidism. OBJETIVO: Establecer el impacto del estadio clínico en los niveles de vitamina D nativa en pacientes con enfermedad renal crónica (ERC) sin diálisis. MÉTODOS: Estudio realizado en Manizales, Colombia, una ciudad tropical ubicada a 2,200 metros de altura sobre el nivel del mar, sin variaciones estacionales importantes a lo largo del año. Se incluyeron pacientes mayores de 18 años, con enfermedad renal crónica estadio 2 a 5 sin tratamiento dialítico. En ellos se evaluaron variables demográficas, antropométricas, grado de exposición solar, etiología de la enfermedad, y variables de laboratorio relacionadas con desórdenes óseos y minerales. Para cada estadío clínico se evaluó la correlación entre los niveles de vitamina D y los resultados de las pruebas de laboratorio relacionadas con desordenes óseos y minerales, exposición solar y etnia. RESULTADOS: Se evaluaron 331 pacientes, con una edad media de 71 años, la mayoría mestizos (71%), 173 mujeres. La principal etiología de ERC fue nefropatía hipertensiva (33.2%). El 21.1% de los pacientes tenían niveles normales de vitamina D, fueron insuficientes en 70.1% y 8.8% en déficit. Se detectó correlación negativa, entre los niveles de vitamina 25(OH)D y los valores de creatinina, fósforo, producto calcio x fósforo, PTH, proteínas en orina de 24 horas e IMC. Correlación positiva para el calcio y la albumina. Se encontró significancia estadística positiva entre los niveles de vitamina 25(OH)D y la exposición solar para los estadios 3b y 4. CONCLUSIONES: En pacientes con ERC es comun detectar bajos niveles de 25(OH)D, los cuales pueden contribuir a la generación de hiperparatiroidismo secundario.

Use of Extended-Release Calcifediol to Treat Secondary Hyperparathyroidism in Stages 3 and 4 Chronic Kidney Disease.

BACKGROUND/AIMS: Vitamin D insufficiency and secondary hyperparathyroidism (SHPT) are associated with increased morbidity and mortality in chronic kidney disease (CKD) and are poorly addressed by current treatments. The present clinical studies evaluated extended-release (ER) calcifediol, a novel vitamin D prohormone repletion therapy designed to gradually correct low serum total 25-hydroxyvitamin D, improve SHPT control and minimize the induction of CYP24A1 and FGF23. METHODS: Two identical multicenter, randomized, double-blind, placebo-controlled studies enrolled subjects from 89 US sites. A total of 429 subjects, balanced between studies, with stage 3 or 4 CKD, SHPT and vitamin D insufficiency were randomized 2:1 to receive oral ER calcifediol (30 or 60 µg) or placebo once daily at bedtime for 26 weeks. Most subjects (354 or 83%) completed dosing, and 298 (69%) entered a subsequent open-label extension study wherein ER calcifediol was administered without interruption for another 26 weeks. RESULTS: ER calcifediol normalized serum total 25-hydroxyvitamin D concentrations (>30 ng/ml) in >95% of per-protocol subjects and reduced plasma intact parathyroid hormone (iPTH) by at least 10% in 72%. The proportion of subjects receiving ER calcifediol who achieved iPTH reductions of ≥30% increased progressively with treatment duration, reaching 22, 40 and 50% at 12, 26 and 52 weeks, respectively. iPTH lowering with ER calcifediol was independent of CKD stage and significantly greater than with placebo. ER calcifediol had inconsequential impact on serum calcium, phosphorus, FGF23 and adverse events. CONCLUSION: Oral ER calcifediol is safe and effective in treating SHPT and vitamin D insufficiency in CKD.

Low-Grade Persistent Hyperparathyroidism After Pediatric Renal Transplant.

OBJECTIVES: Hyperparathyroidism, a frequent complication of chronic kidney disease, persists after renal transplant. Our aims were to examine the status of parathyroid hormone levels and to determine the clinical and biochemical risk factors of persistent hyperparathyroidism after transplant. MATERIALS AND METHODS: Our study included 44 pediatric renal transplant recipients with stable graft function. Median follow-up after transplant was 17.5 months (range, 12-126 mo). Patients did not receive routine vitamin D or calcium supplements after transplant, and none had undergone previous parathyroidectomy. Bone mineral densitometry of the lumbar spine was measured. RESULTS: Fifteen patients (34%) had parathyroid hormone levels greater than 70 pg/mL (normal range, 10-70 pg/mL). Duration of dialysis before transplant was longer in patients with persistent hyperparathyroidism. Mean serum bicarbonate levels were significantly lower in patients with persistent hyperparathyroidism than in patients without persistent hyperparathyroidism after transplant. A significant negative correlation was noted between parathyroid hormone level and serum bicarbonate level. Another significant negative correlation was shown between parathyroid hormone level and z score. CONCLUSIONS: We found that persistent hyperparathyroidism is related to longer dialysis duration, lower serum bicarbonate level, and lower z score. Pretransplant dialysis duration is an important predictor of persistent hyperparathyroidism. Early identification of factors that contribute to persistent hyperparathyroidism after transplant could lead to treatment strategies to minimize or prevent its detrimental effects on bone health and growth in pediatric transplant recipients.

Salivary levels of calcium, phosphorus, potassium, albumin and correlation with serum biomarkers in hemodialysis patients.

OBJECTIVES: Evidences suggest that hemodialysis patients have reduced salivary flow and changes in the composition of salivary secretion. These changes may reflect local and systemic disorders. The objectives of this study were to compare the salivary levels of calcium (Ca), phosphorus (P), potassium (K) and albumin in hemodialysis patients and healthy subjects, and to investigate a possible correlation between their serum and salivary levels. DESIGN: A case-control study was conducted with 60 hemodialysis patients (HD group) and 37 systemically healthy individuals (control group). Stimulated saliva samples were collected for biochemical analysis (Ca, P, K and albumin). Serum data were collected in the HD group. Statistical analysis included t-test, Pearson correlation and simple linear regression. RESULTS: The HD group exhibited higher salivary levels of Ca, P, and albumin (p<0.05). There was a significant positive correlation between serum PTH and salivary phosphorus (r=0.342, p=0.009), and between serum PTH and salivary potassium (r=0.306, p=0.020). An increase of 100 pg/dL in serum PTH was associated with an elevation of salivary P levels (0.34 mg/dL, p=0.009), and salivary K levels (0.20 mmol/dL, p=0.02), in the HD group. CONCLUSIONS: The findings suggest that HD patients present increased levels of salivary components (Ca, P, and albumin), and changes commonly observed in HD patients, such as hyperparathyroidism, appear to have an influence on salivary composition.

HRPT2- (CDC73) RELATED HEREDITARY HYPERPARATHYROIDISM: A CASE SERIES FROM WESTERN INDIA.

OBJECTIVE: To describe a case series of HRPT2- (CDC73) related hereditary primary hyperparathyroidism (PHPT) from western India. METHODS: We present a case series of 4 families (7 patients) with PHPT caused by CDC73 gene mutations. RESULTS: The mean age of presentation of the 4 index cases was 27.25 ± 9.8 years. Two family members were identified through biochemical screening (Cases 1b and 2b), while 1 mutation-positive family member did not manifest any features of PHPT or hyperparathyroidism jaw tumor syndrome (HPT-JT) syndrome (Case 2c). Biochemistry showed increased serum calcium (mean: 13.21 ± 1.24 mg/dL), low serum phosphorus (mean: 1.78 ± 0.44 mg/dL), and high parathyroid hormone (PTH, mean: 936 ± 586.9 pg/mL). All patients had a uniglandular presentation and underwent single adenoma excision initially except Cases 2a and 2b, who underwent subtotal parathyroidectomy at baseline. Two cases experienced PHPT recurrence (Cases 3 and 4), while 1 remained uncured due to parathyroid carcinoma (Case 1a). Other associated syndromic features like ossifying jaw fibromas were present in 2 patients, renal cysts in 3 patients, and uterine involvement in 2 patients. Two families had novel germline CDC73 mutations (Families 1 and 3), while the other 2 had reported mutations. Family 2 had familial isolated PHPT without any other features of HPT-JT syndrome. CONCLUSION: Our findings reaffirm the need for genetic analysis of patients with PHPT, especially those with younger age of disease onset; recurrent disease; and associated features like polycystic kidneys, endometrial involvement, ossifying jaw tumors, or parathyroid carcinoma.

A novel rat model of vitamin D deficiency: safe and rapid induction of vitamin D and calcitriol deficiency without hyperparathyroidism.

Vitamin D deficiency is associated with a range of clinical disorders. To study the mechanisms involved and improve treatments, animal models are tremendously useful. Current vitamin D deficient rat models have important practical limitations, including time requirements when using, exclusively, a vitamin D deficient diet. More importantly, induction of hypovitaminosis D causes significant fluctuations in parathyroid hormone (PTH) and mineral levels, complicating the interpretation of study results. To overcome these shortcomings, we report the successful induction of vitamin D deficiency within three weeks, with stable serum PTH and minerals levels, in Wistar rats. We incorporated two additional manoeuvres compared to a conventional diet. Firstly, the vitamin D depleted diet is calcium (Ca) enriched, to attenuate the development of secondary hyperparathyroidism. Secondly, six intraperitoneal injections of paricalcitol during the first two weeks are given to induce the rapid degradation of circulating vitamin D metabolites. After three weeks, serum 25-hydroxyvitamin D3 (25D) and 1,25-dihydroxyvitamin D3 (1,25D) levels had dropped below detection limits, with unchanged serum PTH, Ca, and phosphate (P) levels. Therefore, this model provides a useful tool to examine the sole effect of hypovitaminosis D, in a wide range of research settings, without confounding changes in PTH, Ca, and P.

Cinacalcet normalizes serum calcium in a double-blind randomized, placebo-controlled study in patients with primary hyperparathyroidism with contraindications to surgery.

OBJECTIVE: Primary hyperparathyroidism (PHPT) is diagnosed by the presence of hypercalcemia and elevated or nonsuppressed parathyroid hormone (PTH) levels. Although surgery is usually curative, some individuals fail or are unable or unwilling to undergo parathyroidectomy. In such individuals, targeted medical therapy may be of value. Cinacalcet normalized calcium level and lowered PTH in patients with PHPT in several phase 2 and open-label studies. We compared cinacalcet and placebo in subjects with PHPT unable to undergo parathyroidectomy. DESIGN: Phase 3, double-blind, multi centere, randomized, placebo-controlled study. METHODS: Sixty-seven subjects (78% women) with moderate PHPT were randomized (1:1) to cinacalcet or placebo for ≤28 weeks. MAIN OUTCOME MEASURE: Achievement of a normal mean corrected total serum calcium concentration of ≤10.3 mg/dl (2.575 mmol/l). RESULTS: Baseline median (quartile 1 (Q1), Q3) serum PTH was 164.0 (131.0, 211.0) pg/ml and mean (s.d.) serum Ca was 11.77 (0.46) mg/dl. Serum Ca normalized (≤10.3 mg/dl) in 75.8% of cinacalcet- vs 0% of placebo-treated subjects (P<0.001). Corrected serum Ca decreased by ≥1.0 mg/dl from baseline in 84.8% of cinacalcet- vs 5.9% of placebo-treated subjects (P<0.001). Least squares mean (s.e.m.) plasma PTH change from baseline was -23.80% (4.18%) (cinacalcet) vs -1.01% (4.05%) (placebo) (P<0.001). Similar numbers of subjects in the cinacalcet and placebo groups reported adverse events (AEs) (27 vs 20) and serious AEs (three vs four). Most commonly reported AEs were nausea and muscle spasms. CONCLUSIONS: These results demonstrate that cinacalcet normalizes serum calcium in this PHPT population and appears to be well tolerated.

Prevalence of vitamin D deficiency in peritoneal dialysis patients.

Peritoneal dialysis (PD) patients have a high risk of developing vitamin D deficiency as 25(OH) vitamin D, the precursor of active vitamin D, is lost during dialysis. This cross-sectional study was conducted to investigate the prevalence of vitamin D deficiency among adult Saudi patients on regular PD The data was collected in the summer of 2010 from patients who were on PD for more than six months at the King Khalid University Hospital, Riyadh. We recorded the demographic and clinical parameters for all patients. Blood samples were taken for serum vitamin D level (25 OH), serum parathyroid hormone (PTH) levels and other necessary biochemical parameters. There were 27 patients (11 males and 16 females) with a mean age of 46 (15-78 ± 21) years. Five patients were on continuous ambulatory PD and 22 patients were using automated PD. The average time on PD was 27.5 (6-84 ± 18.5) months. The mean serum vitamin D 25 (OH) level was 16.1 (4.9-41.5 ± 8.23) nmol/L. Sixteen (59.2%) of the patients had levels below 15 nmol/L, while another eight patients (29.6%) had vitamin D levels between 15 and 25 nmol/L, indicating a marked deficiency. The mean serum calcium was 2.2 (1.7-2.6 ± 0.2) mmol/L and the mean serum phosphorous was 1.48 (0.64-2.22 ± 0.37) mmol/L. Fifteen patients (55.5%) had significant hyperparathyroidism (serum PTH levels above 30 pmol/L). Majority of the PD patients in our center had vitamin D deficiency. The possible reasons include chronic renal failure, dietary restrictions, loss of vitamin D and decreased exposure to sunlight.

Effect of paricalcitol on circulating parathyroid hormone in X-linked hypophosphatemia: a randomized, double-blind, placebo-controlled study.

CONTEXT: Hyperparathyroidism occurs frequently in X-linked hypophosphatemia (XLH) and may exacerbate phosphaturia, potentially affecting skeletal abnormalities. OBJECTIVE: The objective of the study was to suppress elevated PTH levels in XLH patients. DESIGN: This was a prospective, randomized, placebo-controlled, double-blind, 1-year trial of paricalcitol, with outcomes measured at entry and 1 year later. SETTING: PATIENTS were recruited from the investigators' clinics or referred from throughout the United States. Data were collected in an in-patient hospital research unit. PATIENTS: Subjects with a clinical diagnosis of XLH and hyperparathyroidism were offered participation and were eligible if they were 9 years old or older and not pregnant, and their serum calcium level was less than 10.7 mg/dL, their 25-hydroxyvitamin D level was 20 ng/mL or greater, and their creatinine level was 1.5 mg/dL or less. INTERVENTION: The intervention for this study was the use of paricalcitol or placebo for 1 year. MAIN OUTCOME MEASURES: Determined prior to trial onset was the change in PTH area under the curve. Secondary outcomes included renal phosphate threshold per glomerular filtration rate, serum phosphorus, serum alkaline phosphatase activity, and (99m)Tc-methylenediphosphonate bone scans. RESULTS: PTH area under the curve decreased 17% with paricalcitol, differing (P = .007) from the 20% increase with placebo. The renal phosphate threshold per glomerular filtration rate increased 17% with paricalcitol and decreased 21% with placebo (P = .05). Serum phosphorus increased 12% with paricalcitol but did not differ from placebo. Paricalcitol decreased alkaline phosphatase activity in adults by 21% (no change with placebo, P = .04). Bone scans improved in 6 of 17 paricalcitol subjects, whereas no placebo-treated subject improved. Hypercalciuria developed in six paricalcitol subjects and persisted from baseline in one placebo subject. CONCLUSIONS: Suppression of PTH may be a useful strategy for skeletal improvement in XLH patients with hyperparathyroidism, and paricalcitol appears to be an effective adjunct to standard therapy in this setting. Although paricalcitol was well tolerated, urinary calcium and serum calcium and creatinine should be monitored closely with its use.

Mechanisms in endocrinology: vitamin D as a potential contributor in endocrine health and disease.

OBJECTIVE: It has been suggested that vitamin D may play a role in the pathogenesis of several endocrine diseases, such as hyperparathyroidism, type 1 diabetes (T1DM), type 2 diabetes (T2DM), autoimmune thyroid diseases, Addison's disease and polycystic ovary syndrome (PCOS). In this review, we debate the role of vitamin D in the pathogenesis of endocrine diseases. METHODS: Narrative overview of the literature synthesizing the current evidence retrieved from searches of computerized databases, hand searches and authoritative texts. RESULTS: Evidence from basic science supports a role for vitamin D in many endocrine conditions. In humans, inverse relationships have been reported not only between blood 25-hydroxyvitamin D and parathyroid hormone concentrations but also with risk of T1DM, T2DM, and PCOS. There is less evidence for an association with Addison's disease or autoimmune thyroid disease. Vitamin D supplementation may have a role for prevention of T2DM, but the available evidence is not consistent. CONCLUSIONS: Although observational studies support a potential role of vitamin D in endocrine disease, high quality evidence from clinical trials does not exist to establish a place for vitamin D supplementation in optimizing endocrine health. Ongoing randomized controlled trials are expected to provide insights into the efficacy and safety of vitamin D in the management of endocrine disease.

Beneficial effects of selective vitamin D receptor activation by paricalcitol in chronic kidney disease.

In chronic kidney disease patients, active vitamin D level progressively declines in the course of the disease. This phenomenon is accompanied by elevation of parathyroid hormone, resulting in secondary hyperparathyroidism (SHPT), increased phosphorus levels, and hypocalcemia. All these disorders are associated with high rates of cardiovascular morbidity and mortality in these patients. Many vitamin D analogs have been approved for the treatment of SHPT in renal patients. Currently, new and more selective vitamin D receptor activators (VDRAs) have been introduced in this therapy with the aim of reducing SHPT without the hypercalcemia and hyperphosphatemia associated with the use of nonselective VDRAs. In addition, amelioration in hypertension, albuminuria, insulin resistance, and inflammation have been suggested as consequences of vitamin D receptor (VDR) activation. In this work, we summarize the beneficial effects attributed to paricalcitol, the only selective, new generation VDRA, currently available in Europe and the USA, with proven efficacy in the control of SHPT both in hemodialysis (HD) and pre-dialysis patients. Paricalcitol exerts less calcemic and phosphatemic effects than other VDRAs and prevents deleterious bone resorption. Moreover, paricalcitol-based therapy has been related to beneficial effects that could favor survival rates in chronic kidney disease patients. These benefits include anti-inflammatory and antithrombotic effects, the inhibition of vascular smooth muscle cell proliferation, the reninangiotensin system, vascular calcification, and regression of left ventricular hypertrophy, which could reduce the risk of cardiovascular mortality.

Vitamin D treatment in primary hyperparathyroidism: a randomized placebo controlled trial.

CONTEXT: Low 25-hydroxyvitamin D levels are common in patients with primary hyperparathyroidism (PHPT) and associated with higher PTH levels and hungry bone syndrome after parathyroidectomy (PTX). However, concerns have been raised about the safety of vitamin D supplementation in PHPT. OBJECTIVE: We aimed to assess safety and effects on calcium homeostasis and bone metabolism of supplementation with high doses of vitamin D in PHPT patients. DESIGN, SETTING: This was an investigator-initiated double-blind, randomized, placebo-controlled, parallel-group trial from a single center. PATIENTS: Forty-six PHPT patients were recruited, with a mean age of 58 (range 29-77) years, and 35 (76%) were women. INTERVENTIONS: Intervention included daily supplementation with 70 µg (2800 IU) cholecalciferol or identical placebo for 52 weeks. Treatment was administered 26 weeks before PTX and continued for 26 weeks after PTX. MAIN OUTCOME MEASURES: PTH, calcium homeostasis, and bone metabolism were evaluated. RESULTS: Preoperatively, 25-hydroxyvitamin D increased from 50 to 94 nmol/L in the treatment group and decreased from 57 to 52 nmol/L in the placebo group (P < .001). Compared with placebo, vitamin D decreased PTH significantly by 17% before PTX (P = .01), increased lumbar spine bone mineral density by 2.5% (P = .01), and decreased C-terminal ß-CrossLaps by 22% (P < .005). The trabecular bone score did not change in response to treatment, but improved after PTX. Postoperatively, PTH remained lower in the cholecalciferol group compared with the placebo group (P = .04). Plasma creatinine and plasma and urinary calcium did not differ between groups. CONCLUSIONS: Daily supplementation with a high vitamin D dose safely improves vitamin D status and decreases PTH in PHPT patients. The vitamin D treatment is accompanied by reduced bone resorption and improved bone mineral density before operation.

[Hormonal and metabolic disorders as systemic factor for the formation of urinary calculi].

In patients suffering from urolithiasis, metabolic diagnostics often reveals abnormalities contributing to the formation of stones: hypocitraturia, hyper- and hypocalcemia, hypercalciuria, hypomagnesemia/hypomagnesuria, hyperoxalaturia, etc. Before surgery, complex biochemical examination of blood and 24-hourcollection urine in 82 patients with urolithiasis was performed. The analysis of the main laboratory parameters of carbohydrate, lipid, calcium and phosphorus and purine metabolism found the prevalence of violations of calcium and phosphorus metabolism in these patients. Dyslipidemia was diagnosed in 31 (37.8%) patients. There was a significant positive correlation between serum total cholesterol and serum total calcium (rs = 0.3315, P = 0.0103). Low serum calcium levels were associated with hyperoxalaturia (rs = -0.4270, P = 0.0295). There was a significant effect of natriuria on urinary excretion of oxalate (rs = 0.6107, P = 0.0001), Mg (rs = 0.4156, P = 0.0096) and K (rs = 0.5234, P = 0.00005). The study shows the role of magnesium in the prevention of recurrence and manifestation of urolithiasis. The combination of two or more types of hormonal and metabolic disorders increases the incidence of recurrent stones. Timely correction of hormonal-metabolic status allows to reduce the risk of stone formation, and hospitalization attributable to the complications associated.

Molecular and clinical analysis of a neonatal severe hyperparathyroidism case caused by a stop mutation in the calcium-sensing receptor extracellular domain representing in effect a human 'knockout'.

OBJECTIVE: Loss-of-function calcium-sensing receptor (CAR) mutations cause elevated parathyroid hormone (PTH) secretion and hypercalcaemia. Although full Car deletion is possible in mice, most human CAR mutations result from a single amino acid substitution that maintains partial function. However, here, we report a case of neonatal severe hyperparathyroidism (NSHPT) in which the truncated CaR lacks any transmembrane domain (CaR(R392X)), in effect a full CAR 'knockout'. CASE REPORT: The infant (daughter of distant cousins) presented with hypercalcaemia (5.5-6  mmol/l corrected calcium (2.15-2.65)) and elevated PTH concentrations (650-950  pmol/l (12-81)) together with skeletal demineralisation. NSHPT was confirmed by CAR gene sequencing (homozygous c.1174C-to-T mutation) requiring total parathyroidectomy during which only two glands were located and removed, resulting in normalisation of her serum PTH/calcium levels. DESIGN AND METHODS: The R392X stop codon was inserted into human CAR and the resulting mutant (CaR(R392X)) expressed transiently in HEK-293 cells. RESULTS: CaR(R392X) expressed as a 54  kDa dimeric glycoprotein that was undetectable in conditioned medium or in the patient's urine. The membrane localisation observed for wild-type CaR in parathyroid gland and transfected HEK-293 cells was absent from the proband's parathyroid gland and from CaR(R392X)-transfected cells. Expression of the mutant was localised to endoplasmic reticulum consistent with its lack of functional activity. CONCLUSIONS: Intriguingly, the patient remained normocalcaemic throughout childhood (2.5 mM corrected calcium, 11 pg/ml PTH (10-71), age 8 years) but exhibited mild asymptomatic hypocalcaemia at age 10 years, now treated with 1-hydroxycholecalciferol and Ca2+ supplementation. Despite representing a virtual CAR knockout, the patient displays no obvious pathologies beyond her calcium homeostatic dysfunction.