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

During the past 5 years, we have identified idiopathic hypercalciuria in five of seven patients referred for evaluation of renal glycosuria between 1985 and 1991. The children, all boys, ranged in age from 6 to 12 years. Endocrine function was normal, and none of the patients had hyperparathyroidism, hypercalcemia, renal tubular acidosis, or other secondary causes of hypercalciuria. The calcium/creatinine ratio in a fasting urine specimen was elevated in all five children who had hypercalciuria, with a mean value (+/- SD) of 0.34 +/- 0.06 (normal, < 0.2). In one child who had renal colic with spontaneous passage of gravel-like material, the idiopathic hypercalciuria persisted after 1 week on a diet containing 2000 mg of sodium and 300 mg of calcium. On the basis of studies that examined the site along the nephron responsible for hypercalciuria in rats with streptozocin-induced diabetes, we speculate that in children with renal glycosuria, there is defective reabsorption of glucose and calcium in the straight portion of the proximal tubule or in the collecting duct. It is likely that a similar mechanism accounts for the idiopathic hypercalciuria in children with diabetes mellitus.
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PMID:Hypercalciuria in children with renal glycosuria: evidence of dual renal tubular reabsorptive defects. 841 May 29

Nephrocalcinosis is uncommon in childhood, the main causes are renal tubular acidosis, hyperparathyroidism and medullary sponge kidney. It is also seen where there is hypercalcaemia or hypercalciuria of any aetiology; We report nephrocalcinosis in an 18-month-old infant with metaphyseal chondrodysplasia type Jansen and also in a neonate with McCune Albright syndrome who displayed atypical skeletal appearances and had multiple ovarian cysts.
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PMID:Two unusual cases of nephrocalcinosis in infancy. 143 81

Fifty-five children (34 boys, 21 girls; age range, 1 day to 18 years) with increased echogenicity of the renal medullary pyramids at ultrasound evaluation were identified. The clinical diagnoses associated with hyperechoic medullary pyramids could be separated based on the presence or absence of hypercalciuria. Patients with drug-induced hypercalciuria included 10 infants treated with furosemide, two treated with long-term steroid therapy, and one treated with excessive amounts of vitamin D. Other clinical conditions associated with hypercalciuria included renal tubular acidosis (n = 10), Bartter syndrome (n = 5), hyperparathyroidism (n = 3), Williams syndrome (n = 2) and medullary sponge kidney (n = 2). Ten children with transient renal insufficiency and three with sickle cell disease had normal urine calcium concentration. Isolated disease entities accounted for the remainder of cases. A specific diagnosis can usually be made in a patient with hyperechoic renal medullary pyramids by using a systematic clinical approach that includes evaluation of patient age, serum and urine calcium concentration, and renal function.
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PMID:Hyperechoic renal medullary pyramids in infants and children. 188 61

Our primary objective was to test the hypothesis that a defect in acidification is more common in patients who have idiopathic calcium phosphate kidney stones than in those whose stones are formed mainly of calcium oxalate. Additionally, other risk factors might differ for these 2 stone types. Urine pH was measured serially over 24 hours, and along with ammonium and titratable acid, it was measured before and serially after ingestion of ammonium chloride in 3 groups of subjects: 24 patients with predominantly calcium phosphate stones, 30 patients with calcium oxalate stones, and 15 health non-stone-formers. Twenty-six parameters potentially related to stone formation and acidification were assayed on urines collected over 24 hours, and 15 parameters on blood. The data base was a computerized list of 5900 analyses of stones from patients living in Newfoundland. Patients not known by their physician to have had urinary tract infection, anatomical abnormality, hyperparathyroidism, or renal tubular acidosis were asked to participate in the study. Differences between means were considered significant if p values were less than 0.05 for F by analysis of variance and also less than 0.01 by t-test. In all patients with calcium oxalate stones and all non-stone-formers, urine acidified to pH less than 5.25, but in 8 of the 23 phosphate stone formers who completed the ammonium chloride study urine failed to acidify to pH less than 5.25. As all 8 had normal values for venous pH, total CO2, and chloride, they were considered to have incomplete renal tubular acidosis (IRTA). The 8 phosphate stone formers with IRTA had greater mean values for urine pH on all 9 specimens collected serially over 24 hours (all means greater than 6.2), and after administration of ammonium chloride (p less than 0.01), as well as lower mean values for urine titratable acid excretion (p less than 0.01), both after administration of ammonium chloride and in 24-hour urine samples, compared with the remaining phosphate stone formers whose urine acidified and the oxalate and non-stone-forming control groups. Nearly all the phosphate stone formers had 1 or more risk factors for stone formation, but with frequencies not significantly higher than those found in the oxalate group. Hypercalciuria and hypocitruria were the commonest, but increased oxalate or urate also occurred. Thus, idiopathic calcium phosphate stone formation can be associated with 1 or more of several risk factors, and, with the possible exception of those with IRTA, treatment should be similar to that given to patients with calcium oxalate stones.
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PMID:Comparison of patients with idiopathic calcium phosphate and calcium oxalate stones. 195 78

On the basis of 3 infants with primary congenital hyperparathyroidism we discuss problems in the early diagnosis and interpretation of the results of laboratory findings. The lack of increased renal echogenicity and hypercalciuria, which is regularly present in idiopathic hypercalcaemia is emphasized. In contrast to secondary hyperparathyroidism caused by prolonged hypocalcaemia, e.g. in patients treated by longterm haemodialysis, the aetiology of primary hyperparathyroidism (pHPT) remained unclear although molecular genetic studies suggest that the development of parathyroid adenoma may be due to gene mutation in a cell. Congenital pHPT is a particularly rare condition usually due to diffuse hyperplasia of all parathyroid glands. Its inheritance is known to be autosomal. Three infants with congenital primary hyperparathyroidism were treated at the Child Health Centre in the years 1987-1988.
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PMID:Primary hyperparathyroidism in infants. Diagnostic and therapeutic difficulties. 203 3

Over a period spanning six months, 69 patients with lithiasis were selected for evaluation of mineral metabolism. Hypercalciuria, particularly renal, was the metabolic disorder that was commonly detected. A high incidence of altered uric acid metabolism was also observed. The importance of correct diagnosis and treatment of hyperparathyroidism is underscored because of the extraordinary benefit afforded to these patients. Correct patient selection has resulted in a lower incidence of those with normal metabolic parameters and has thus maximized the usefulness of these studies.
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PMID:[Metabolic changes in the patient with recurring lithiasis. Our cases]. 206 24

Three siblings with neonatal familial hyperparathyroidism diagnosed at age 4 months, 2 months, and 5 days, respectively, were treated. Hypercalciuria, nephrocalcinosis, and renal tubular acidosis were present in each child. In all three, there were higher responses of serum parathyroid hormone to serum calcium and higher elevation of serum calcium with oral calcium loading. The metabolism of vitamin D and calcitonin seemed to be intact. Hypercalcemia associated with the abnormal response of parathyroid hormone secretion disappeared when the children passed the age of approximately 2 years, although renal tubular acidosis and nephrocalcinosis remained. An autosomal recessive inheritance seems likely.
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PMID:Self-limited neonatal familial hyperparathyroidism associated with hypercalciuria and renal tubular acidosis in three siblings. 216 60

Urinary calcium excretion (UCa) is normal several weeks following subtotal nephrectomy (Nx) in the rat, despite factors such as magnified solute load per nephron which should promote hypercalciuria. To define the levels of UCa during the first few weeks after Nx and to determine if the development of compensatory mechanisms governing renal conservation of calcium are detectable, we measured UCa in Nx and sham Nx rats with matched food intake (10 g/day) from 10 days before through 20 days following Nx. In the sham Nx animals, UCa rose during the first 5 days following surgery from 27 +/- 8 to 66 +/- 5 microM/day and then plateaued for the remaining time. In Nx rats, UCa also rose during the first 5 postoperative days from 23 +/- 5 to 110 +/- 10 microM/day (Nx vs. sham Nx, p less than 0.05), but then fell over the next 3 days to levels observed simultaneously in sham Nx animals. The rise in UCa after Nx, but not after sham Nx, was associated with a doubling of urine flow rate and increased urinary titratable acid excretion. In parathyroidectomized rats, UCa also rose following Nx; however, maximum UCa was then sustained for at least 4 days. In an additional sham Nx group fed 20 g/day, no increase in UCa occurred following surgery. Thus, hypercalciuria is present following Nx in the rat, in part possibly attributable to increased acid excretion. The transient nature of calciuria reflects an adaptive phenomenon, most likely hyperparathyroidism. Diminished food intake following surgery independently contributes to hypercalciuria, regardless of the status of renal mass.
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PMID:Early effects of subtotal nephrectomy and food restriction on urinary calcium in the rat. 227 4

The crystallization of calcium oxalate in the urine of patients with hyperparathyroidism and hyperthyroidism was studied using a mixed suspension mixed product removal (MSMPR) system. In addition, calcium metabolism in hyperthyroidism and its relationship to urolithiasis was investigated. The urines from all the three groups (normal subjects, hyperparathyroid and hyperthyroid patients) showed reduced nucleation rates and increased growth rates in comparison with the control synthetic urine. The nucleation rate was not significantly different between the three human urine groups, while the growth rate was significantly higher in the hyperparathyroid group compared to the normal and hyperthyroid groups. Crystal volume (suspension density) in the hyperparathyroid group was approximately twice that in the other two groups. Serum and ionized calcium levels in hyperparathyroid patients were higher than in normal subjects, while hyperthyroid patients had levels only slightly higher than those in normal subjects. The hyperparathyroid and hyperthyroid groups differed significantly from the normal group in urinary calcium excretion. These two groups also showed significantly higher levels of serum alkaline phosphatase and urinary hydroxyproline than did the normal group. Although hyperthyroid patients have a calcium metabolism similar to hyperparathyroid patients, the incidence of urolithiasis is no different between hyperthyroid and normal subjects. The results of both crystallization and calcium metabolism in hyperparathyroid patients were not significantly different between those with and without urolithiasis. The result of crystallization was also not significantly different between hyperparathyroid patients with and without hypercalciuria. This study suggests that hypercalciuria alone does not produce urinary stones and that urine from hyperparathyroid patients may contain promotors of calcium oxalate crystallization and calcium stone formation.
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PMID:Calcium oxalate crystal formation in patients with hyperparathyroidism and hyperthyroidism and related metabolic disturbances. 230 55

We report results for adjusted ionized calcium (at pH 7.4) and actual ionized calcium (at actual pH) in capillary blood from 183 patients with disorders of calcium metabolism (primary hyperparathyroidism, secondary hyperparathyroidism of malabsorption, primary hypoparathyroidism, Paget's disease, acromegaly, hypercalcemia of malignancy, osteoporosis, sarcoidosis, idiopathic hypercalciuria, and familial hypocalciuric hypercalcemia). The correlation and the equation for the linear regression between adjusted ionized calcium (y) and actual ionized calcium (x) were y = 1.011x + 0.005 mmol/L, r = 0.992, Sy,x = 0.021 mmol/L. Results were similar within each diagnostic group. Consistent agreement between adjusted and ionized calcium was observed in 96.7% of patients representing a variety of the most frequently encountered disorders of calcium metabolism. Thus we find adjusted ionized calcium to be as useful as actual ionized calcium for evaluation of patients with such disorders. Adjusted ionized calcium may therefore also be a logical choice for establishing agreement between laboratories for reference intervals in healthy adults.
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PMID:Adjusted ionized calcium (at pH 7.4) and actual ionized calcium (at actual pH) in capillary blood compared for clinical evaluation of patients with disorders of calcium metabolism. 231 Dec 30


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