Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Primary hyperparathyroidism manifests biochemically as a disturbance in serum calcium homeostasis. The central organ setting serum calcium level is the kidney. It not only has the highest rate of active calcium transport, but the kidney also modulates serum calcium homeostasis by virtue of its endocrine role in 1,25-hydroxyvitamin D secretion. Receptors for PTH are widely expressed throughout the renal tubule and are involved in both calcium transport and endocrine function. Biochemical manifestations of primary hyperparathyroidism by the kidney include increased tubular reabsorption of calcium, decreased reabsorption of phosphate and bicarbonate, and hypercalciuria. A reduction in glomerular filtration may occur in some patients with primary hyperparathyroidism, which perturbs the diagnostic relationships among biochemical variables and induces further increases in PTH secretion. Parathyroidectomy rapidly restores the biochemical abnormalities to normal apart from chronic reduced glomerular filtration. Clinical manifestations are nephrolithiasis, which is common, and nephrocalcinosis, which is uncommon. Nephrocalcinosis may occur with or without nephrolithiasis. Risk factors for nephrolithiasis are oversaturation of urine with calcium phosphate and with calcium oxalate. Risk factors for nephrocalcinosis are not clearly defined. Parathyroidectomy greatly reduces the incidence of nephrolithiasis but has little effect on nephrocalcinosis.
 ...
PMID:Primary hyperparathyroidism and the kidney: biochemical and clinical spectrum. 1241 83

Autosomal dominant hypocalcemia (ADH) caused by activating mutations of calcium-sensing receptor (CaSR) is characterized by hypocalcemia with inappropriately low concentration of PTH and relative hypercalciuria. Active vitamin D treatment often leads to nephrolithiasis and renal impairment in patients with ADH. However, differential diagnosis between ADH and idiopathic hypoparathyroidism is sometimes very difficult. Here, we report a mutation of CaSR and its functional property found in three generations of a Japanese family. The proband developed seizures at 7 days of age. His mother and elder sister were discovered to have hypoparathyroidism by family survey, but his father was normocalcemic. His grandfather developed heart failure and was found to have hypoparathyroidism. All affected members had been treated with active vitamin D3 and bilateral nephrolithiasis were detected in three of them. DNA sequencing revealed that all affected patients had a heterozygous mutation in CaSR gene that causes proline to leucine substitution at codon 221 (P221L). In vitro functional analysis of the mutant CaSR by measuring inositol 1,4,5-trisphosphate production in response to changes of extracellular Ca indicated that this mutation is an activating one and responsible for ADH in this family. Therefore, careful monitoring of urinary Ca excretion before and during treatment of PTH-deficient hypoparathyroidism is very important, and screening of CaSR mutation should be considered in patients with relative hypercalciuria or with a family history of hypocalcemia.
 ...
PMID:A family of autosomal dominant hypocalcemia with an activating mutation of calcium-sensing receptor gene. 1273 14

Children with myelomeningocele experience difficulty with ambulation, which leads to immobilization and secondary loss of bone mineral density (BMD). In addition, non-ambulatory myelomeningocele patients have higher urinary calcium losses than their ambulatory counterparts. Hydrochlorothiazide (HCTZ) is known to reduce urinary calcium loss and increase BMD in non-myelomeningocele patients with hypercalciuria. This study examines the effect of HCTZ on urinary calcium and BMD in non-ambulatory children with myelomeningocele. Thirteen of 20 non-ambulatory patients with myelomeningocele completed the year-long randomized double-blinded study (placebo = 7 and HCTZ = 6). Evaluation included electrolytes, PTH, osteocalcin, 1, 25-OH vitamin D, urinary pyridinolines/deoxypyridinolines (U(pyr/dpyr)), urinary calcium/creatinine (U(Ca/Cr)), and forearm BMD (dual X-ray absorptiometry). Follow-up electrolytes were obtained at 1-2, 6, and 12 months and U(Ca/Cr) and BMD was obtained again at 12 months. There were no initial differences between the placebo and HCTZ groups. U(Ca/Cr) decreased in the HCTZ group after treatment (0.20+/-0.09 vs. 0.04+/-0.02, p<0.05). However, forearm BMD ( z-scores) after 1 year remained unchanged in both the HCTZ (-5.95+/-0.98 to -5.86+/-0.92) and placebo (-7.19+/-0.69 to -6.67+/-0.63) groups. While use of HCTZ for 1 year did not affect BMD, it reduced urinary calcium excretion in non-ambulatory children with myelomeningocele.
 ...
PMID:Bone mineral density in children with myelomeningocele: effect of hydrochlorothiazide. 1288 72

We have found recently that excluding subjects with low serum 25OHD has a significant impact on the PTH reference range (10-46 ng/liter instead of 10-65 ng/liter with the same assay). However, before being used routinely, this new range had to be clinically validated. We thus reviewed the chart of 708 consecutive osteopenic patients who were referred to our unit for a biological exploration in search of secondary causes for their low bone mass. They were classified into two groups. Group 1 (n = 360) included the patients for whom no reasons for high PTH were found after examination of their chart. Group 2 (n = 348) included patients with one of the following potential reasons for an increased PTH concentration: hyper- or hypocalcemia, normocalcemic primary hyperparathyroidism (PHPT), renal hypercalciuria, vitamin D insufficiency, chronic renal failure, use of bisphosphonates, and any chronic disease known to potentially alter calcium metabolism. Among the 360 group 1 patients, 15 (4.2%) had a serum PTH level more than 46 ng/liter, which is not different from the theoretical rate of 3% of normal subjects whose serum PTH may be above the 97th centile of the reference (chi(2) = 2.8; NS). Forty-two group 2 patients had a surgically proven PHPT. Among these, serum PTH was </=65 ng/liter in 17 (40.5%) and </=46 ng/liter in 5 (12%). In conclusion, our proposed PTH reference range allows to identify fewer patients with mild surgically proven PHPT who have a normal serum PTH concentration, without inducing an increase in the rate of falsely high PTH.
 ...
PMID:The use in clinical practice of parathyroid hormone normative values established in vitamin D-sufficient subjects. 1291 24

Hypoparathyroidism is one of the few remaining hormonal insufficiency states for which replacement therapy is unavailable. Previous short-term controlled trials have shown PTH to be a safe and effective treatment of hypoparathyroidism. In this randomized, parallel group, open-label trial, we compared synthetic human PTH-(1-34) (PTH) with conventional therapy, calcitriol and calcium, over a 3-yr period. Twenty-seven patients with confirmed hypoparathyroidism, aged 18-70 yr, were randomized to either twice daily sc PTH or oral calcitriol and calcium. The primary end points were calcium levels in serum and urine. Secondary end points were creatinine clearance, markers of bone turnover, and bone mineral density. Throughout the 3-yr study period, serum calcium levels were similar in both treatment groups within or just below the normal range. Mean urinary calcium excretion was within the normal range from 1-3 yr in PTH-treated patients, but remained above normal in the calcitriol group. Bone mineral content and bone mineral density showed no significant between-group differences over the 3-yr study period. We conclude that treatment with twice daily sc PTH provides a safe and effective alternative to calcitriol therapy and is able to maintain normal serum calcium levels without hypercalciuria for at least 3 yr in patients with hypoparathyroidism.
 ...
PMID:Long-term treatment of hypoparathyroidism: a randomized controlled study comparing parathyroid hormone-(1-34) versus calcitriol and calcium. 1297 Feb 89

We studied bone mineral metabolism changes complicated by acute gastroenteritis in a clinical acute metabolic acidosis milieu where we observed hypercalcemia, hypercalciuria, and elevated urinary hydroxyproline excretion. Serum magnesium and plasma osteocalcin, alkaline phosphatase, and IGF-1 levels were decreased. No significant changes in serum inorganic phosphate and plasma PTH, calcitonin, or 25-hydroxy vitamin D3 levels were detected. All abnormalities disappeared with the correction of acidosis. Observed hypercalcemia seems to be the result of increased calcium efflux from bone due to metabolic acidosis-induced catabolism of type 1 collagen and decreased osteoblastic activity. This study provides data regarding acute metabolic acidosis-induced changes in noninvasive parameters of bone modeling, assessed for the first time in humans.
 ...
PMID:Bone mineral changes in acute metabolic acidosis due to acute gastroenteritis. 1559 94

Hypoparathyroidism patients devided two groups. One group is low PTH group and the other is pseudo hypoparathyroidism group. Hypoparathyroidism in these patients has been managed by 1,25- (OH)(2)D(3) or 1alpha-OHD(3). However inappropriately high doses active vitamin D usually lead to marked hypercalciuria. It is important to control serum Ca level (absolute hypo within normal values) without hypercalciuria.
 ...
PMID:[Vitamin D and its analogs in the treatment of hypoparathyroidism]. 1577 71

Nephrolithiasis is the most important clinical manifestation of primary hyperparathyroidism (PHPT), although nowadays this disorder is often asymptomatic. Clinical or biochemical differences between PHPT patients with and without nephrolithiasis have not been clearly identified in most of the previous studies. The aim of the study was to investigate clinical and biochemical parameters in kidney stone former (SF) and non-stone former (NSF) patients with PHPT in order to identify potential risk factors. Serum and plasma samples from 55 consecutive patients (43 females, 12 males) with PHPT were collected after overnight fasting; 24-h urine collection and a fresh sample of urine for sediment analysis were obtained from all patients. Clinical data were recorded in all. Out of 55 patients, 22 had kidney stones, which were symptomatic in 73%. SFs showed circulating PTH, total and ionized calcium, 1,25 dihydroxyvitamin D3, urinary calcium excretion and 24-h urine oxalate levels significantly higher than NSFs. Hypercalciuria was often concomitant with massive quantities of calcium oxalate crystals in urine sediment. Hypercalciuria and relatively high oxaluria were associated with stone formation with an odds ratio (OR) of 4.0 and 7.0, respectively, which rose to 33.5 when they coexisted. Hypomagnesuria and hypocitraturia were common in at least one third of all PHPT patients, but they were not associated to an increased OR. As expected, they were positively correlated with urine calcium excretion, suggesting that calcium, magnesium and citrate are commonly regulated at renal level. In conclusion, hypercalciuria, higher oxalate excretion and severe PHPT are associated with kidney stones in PHPT.
 ...
PMID:Risk factors associated to kidney stones in primary hyperparathyroidism. 1588 57

The aim of this investigation was to evaluate bone mineral density (BMD), by use of DXA, and bone turnover, in patients with Bartter syndrome (BS). Ten patients (2 with BS type II and 8 with BS type III) were included in the procedure. Age at study varied between 2 and 30 years. During the studies usual treatment with indomethacin, spironolactone, and potassium chloride was maintained. Results were compared with those obtained in the 20 asymptomatic parents. Height of the patients at the time of the study did not differ from reference values (Z-score -1.2 to +0.8). Three patients (1 with BS type II and 2 with BS type III) presented reduced lumbar spine BMD or overt osteopenia (BMD Z-scores: -2.3, -1.3, and -1.1). BMD did not correlate significantly with age. Paternal and maternal femoral neck BMD values correlated significantly with lumbar spine BMD of the patients (r=0.65, P<0.05, and r=0.80, P<0.01). Lumbar spine BMD Z-scores correlated negatively with urinary Ca excretion when values both from patients and parents were jointly analyzed (r=-0.43, P<0.05). Plasma calcium concentration was significantly higher (P<0.001) and plasma phosphate Z-score was significantly lower (P<0.05) in the patients than in the parents. However, no significant differences were observed in values for intact PTH, 1,25 (OH)(2)D(3) and 25 (OH)D(3). Intact PTH values correlated positively with BMD Z-scores at lumbar spine (r=0.45, P<0.05) and at femoral neck (r=0.63, P<0.01). Age-corrected biochemical markers of bone formation (plasma alkaline phosphatase and osteocalcin concentrations) were normal whereas age-corrected markers of bone reabsorption (urinary PYD and DPD excretion) were significantly higher than parental values (P<0.01 and <0.05, respectively). We conclude that: (1) reduced BMD is not an exclusive feature of neonatal BS and it can be also observed in classic BS; (2) the loss of bone mineral is not progressive, probably because of the hypocalciuric effect of indomethacin therapy; and (3) this study did not determine whether loss of bone mass is the cause or the consequence of hypercalciuria although the beneficial effect of indomethacin therapy implies the latter.
 ...
PMID:Bone mineral density and bone turnover in patients with Bartter syndrome. 1594 90

A 19-year-old female patient with hypercalciuria and recurrent nephrolithiasis/urinary tract infection unresponsive to thiazide type diuretics is presented. The patient first experienced nephrolithiasis at the age of 4 years. Afterwards, recurrent passages of stones and urinary tract infection occurred. On diagnostic evaluation at the age of 19 years, she also had hypocitraturia and hypomagnesemia. Her serum calcium concentrations were near the lower limit of normal (8.5-8.8 mg/dl; normal range: 8.5-10.5), her serum magnesium concentrations were 1.15-1.24 mg/dl (normal range: 1.4-2.5) and urinary calcium excretion was 900 mg/24 h. PTH concentrations were increased (110-156 pg/ml; normal range: 10-65). We tried to treat the patient with hydrochlorothiazide at a dose of 50 mg/day. During treatment with thiazide diuretics, PTH concentration remained high and the patient had recurrent urinary tract infections and passages of stones. Serum magnesium concentration did not normalize even under the parenteral magnesium infusion. Her mother had a history of nephrolithiasis 20 years ago. Severe hypomagnesemia in association with hypercalciuria/urinary stones is reported as a rare autosomal recessive disorder caused by impaired reabsorption of magnesium and calcium in the thick assending limp of Henle's loop. Recent studies showed that mutations in the CLDN16 gene encoding paracellin-1 cause the disorder. In exon 4, a homozygous nucleotide exchange (G679C) was identified for the patient. This results in a point mutation at position Glycine227, which is replaced by an Arginine residue (G227R). The mother was heterozygous for this mutation. G227 is located in the fourth transmembrane domain and is highly conserved in the claudin gene family. This case indicates the pathogenetic role of paracellin-1 mutation in familial hypomagnesemia with hypercalciuria and nephrocalcinosis and further underlines the risk of stone formation in heterozygous mutation carriers.
 ...
PMID:An unusual patient with hypercalciuria, recurrent nephrolithiasis, hypomagnesemia and G227R mutation of Paracellin-1. An unusual patient with hypercalciuria and hypomagnesemia unresponsive to thiazide diuretics. 1680 18


<< Previous 1 2 3 4 5 6 7 8 9 10 Next >>