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Query: UMLS:C0020438 (hypercalciuria)
 2,502 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

Increased luminal calcium decreases potassium secretion in microperfused rat distal tubule. To determine if such an effect is also present in vivo, we evaluated renal potassium excretion in 49 children with idiopathic hypercalciuria (urinary excretion of Ca = 5.5 +/- 1.3 mg/kg/day) and in 214 age-matched control children (urinary excretion of Ca = 1.9 +/- 0.3 mg/kg/day). In comparison to controls, hypercalciuric children had significantly increased levels of sodium excretion (fractional excretion of Na = 0.7 +/- 0.3 vs. 0.6 +/- 0.3%, respectively; p less than 0.001) and decreased levels of fractional potassium excretion (7.2 +/- 2.9 vs. 9.2 +/- 3.4%, respectively; p less than 0.001) and of the transtubular potassium concentration gradient (4.2 +/- 1.5 vs. 5.9 +/- 1.5, respectively; p less than 0.001). All indices of potassium excretion correlated significantly and inversely with urinary calcium excretion (p less than 0.001). After an oral calcium load, performed in 30 hypercalciuric children, the increased rates of urinary calcium excretion were accompanied by increased rates of urinary sodium excretion and by a significant decrease in the transtubular potassium concentration gradient. These results support the hypothesis that increased luminal calcium concentration also inhibits renal potassium secretion in man.
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PMID:Renal potassium excretion is reduced in children with idiopathic hypercalciuria. 182 84

Hypercalciuria is one of the main causes of recurrent generation of urinary calcium-containing calculi. 107 patients with recurrent calcium nephrolithiasis were examined and results presented. Concentrations of potassium, sodium, chlorides, calcium, phosphorus, uric acid and creatinine were investigated in serum and urine, as well as indices of acid-base balance in arterial blood. pH-metry, "preliminary" and oral calcium tolerance test were also carried out. The microcomputer data analysis established that the diagnosis of primary hyperparathyroidism may be identified in case of increased serum calcium level before and after calcium load test, the same of parathyroid, and increased urinary cAMP excretion. Renal hypercalciuria is characterized by low blood calcium level in both periods of the oral test, high basal calciuria, increased urinary cAMP excretion and its slight decrease after the oral calcium load test, by a tendency to lower serum magnesium levels in high magnesuria. The patients with absorptive hypercalciuria had an upper normal or increased blood calcium level, a significant calcemic and calciuric "response" to the calcium load, reduction in urinary cAMP elimination and more severe decrease (close to 0) of these indices after oral calcium load and normal magnesium levels in blood and urine. On a base of the "preliminary" test data the patients with relapsing calcium nephrolithiasis and metabolic disorders may be differed from those without calcium and phosphorus metabolic deteriorations. The "preliminary" test defines indications for the oral calcium tolerance test, automatic diagnosis and computer data storage facilitate physician to work and to solve problems of the patients' survey.
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PMID:[The comprehensive examination of patients with recurrent calcium nephrolithiasis]. 185 97

Thirteen urolithiasis patients with unilateral obstructive uropathy were treated with percutaneous nephrostomy (PCN) either for urinary diversion, endopyelotomy, nephrolithtotmy or chemolysis. After percutaneous nephrostomy, the individual urine volume, creatinine clearance (Ccr), urinary absolute and fractional excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were measured separately in timed urine collections from a pigtail catheter and from the urethra. The data showed that Ccr and the absolute urinary excretions of sodium, potassium, calcium, magnesium and inorganic phosphate were significantly lower in the PCN kidney immediately or 2 days after relief of obstruction. The ratio of total urinary calcium excretion to urinary creatinine excretion in the obstructed kidney was significantly greater than that in the contralateral kidney. The fractional excretions of calcium and magnesium increased as renal function decreased. The results showed that when the total Ccr is below normal, the apparent excretion of urinary calcium will be underestimated. However, when the total Ccr of patients is within normal range, hypercalciuria may be detected adequately and thus favors early implementation of an appropriate therapeutic strategy.
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PMID:Reduction of calcium excretion in the stone-forming kidney in unilateral ureteral obstruction. 188 28

Nephrolithiasis is a heterogeneous disorder, with varying chemical composition and pathophysiologic background. Although kidney stones are generally composed of calcium oxalate or calcium phosphate, they may also consist of uric acid, magnesium-ammonium phosphate, or cystine. Stones develop from a wide variety of metabolic or environmental disturbances, including varying forms of hypercalciuria, hypocitraturia, undue urinary acidity, hyperuricosuria, hyperoxaluria, infection with urease-producing organisms, and cystinuria. The cause of stone formation may be ascertained in most patients using the reliable diagnostic protocols that are available for the identification of these disturbances. Effective medical treatments, capable of correcting underlying derangements, have been formulated. They include sodium cellulose phosphate, thiazide, and orthophosphate for hypercalciuric nephrolithiasis; potassium citrate for hypocitraturic calcium nephrolithiasis; acetohydroxamic acid for infection stones; and D-penicillamine and alpha-mercaptopropionylglycine for cystinuria. Using these treatments, new stone formation can now be prevented in most patients.
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PMID:Etiology and treatment of urolithiasis. 196 46

Calcium metabolism and its response to citrate were examined in 51 patients with glaucoma receiving carbonic anhydrase inhibitors (acetazolamide or methazolamide). Metabolic acidosis, hypocitraturia and increased incidence of nephrolithiasis were induced by both drugs. However, the acidosis was milder with methazolamide administration. Normocalciuria was observed in 29 patients and was shown to be a result of low filtered calcium. Renal hypercalciuria in 16 patients was associated with elevated parathyroid hormone but nephrogenic cyclic adenosine monophosphate remained within normal limits. Citrate in the form of potassium citrate (4.3 mmol.) and sodium citrate (4.0 mmol.) did not correct the metabolic acidosis or hypocitraturia but consistently decreased fasting and 24-hour urinary calcium excretion in patients with renal hypercalciuria. This event did not occur in patients with normocalciuria or absorptive hypercalciuria. These results suggest that a small amount of citrate could reverse renal hypercalciuria without correcting the metabolic acidosis.
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PMID:Calcium metabolism in acidotic patients induced by carbonic anhydrase inhibitors: responses to citrate. 201 6

Seventeen hypercalciuria patients (8 control, 9 treatment) with a history of urolithiasis were randomly selected to receive low-calcium, low-oxalate diets with or without the addition of 30 g of dietary fiber as unprocessed wheat bran. Diet alone resulted in a 5.6 percent decrease in calciuria compared with a 23.5 percent decrease with the addition of the fiber. The addition of hydrochlorothiazide and potassium citrate further reduced calciuria by 40.4 percent and 34.5 percent, respectively. Oxaluria was decreased 21.4 percent by diet alone compared with 3.9 percent in the diet and fiber treatment group. Patient compliance to diets was good, and no complications resulted from fiber intake.
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PMID:Effect of unprocessed wheat bran on calciuria and oxaluria in patients with urolithiasis. 215 68

Prophylactic treatment with alkaline citrate in patients with recurrent calcium oxalate (CaOx) stone disease results in reduced CaOx supersaturation and increased urinary citrate. The effects of a single evening dose were compared with those of two and three daily doses in six recurrent CaOx stone formers with hypercalciuria, hypocitraturia or raised calcium/citrate quotients. While on a standardized hospital diet the patients were given 7.5 g (28 mmol) of sodium potassium citrate (URALYT-U) in one, two, and three doses. Fractional urine collections during 24 hours were analyzed for pH, composition, and crystallization risk (CR). All dosage regimens had favourable effects on urinary calcium, citrate, calcium/citrate quotients, and CaOx-CR. The most sustained effect was recorded with three divided doses. Single evening doses resulted in the most pronounced effects between 22.00-06.00 h, thereby counteracting the increased risk of CaOx crystallization during that period. In terms of 24h urine composition the best effect was recorded with alkaline citrate administered three times daily, but because of the favourable response by a single evening dose between 22.00-06.00 h the assumption was made that this dosage regimen might be sufficient to reduce the risk of CaOx crystallization and stone formation. However, the validity of such an assumption can only be established by long-term clinical studies.
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PMID:Effects of different doses of alkaline citrate on urine composition and crystallization of calcium oxalate. 231 66

The effects of sulfur-containing amino acids (SAA) and potassium (K) on urinary excretion and retention of calcium (Ca) of 27 young Japanese women were studied. A basal diet low in protein level (50 g per day) was fortified by meat or soy protein isolate (SPI) to a protein level of 100 g per day, and effects of addition of apple to these high protein diets, and addition of SAA and/or potassium (K) to the high SPI diet, especially on urinary Ca excretion, were studied. The addition of meat which increased protein intake to 100 g caused the increase in apparent absorption and urinary excretion of Ca with increased excretion of urinary sulfur (S), phosphate, ammonia, and titratable acids (TA), whereas addition of SPI did not. The addition of apple to high meat diet decreased absorption and urinary excretion of Ca. Urinary Ca, S, K, ammonia, and TA excretion increased by the addition of SAA to high SPI diet in a manner similar to the meat diet. Consequently, SAA-supplemented diet had a significantly negative effect on Ca retention. In SPI+SAA,K diet period, urinary K excretion markedly increased, and increments in urinary Ca, ammonia, and TA excretion were reversed. These changes observed in SPI+SAA, K diet period were similar to those by adding apple to meat diet without any effect on Ca absorption. The results suggest that the hypercalciuria induced by high meat diet is mainly caused by high content of SAA and may be reversed by the ingestion of K-rich foodstuffs, and soy protein does not induce hypercalciuria because of it contains less SAA than animal protein.
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PMID:Urinary calcium and calcium balance in young women affected by high protein diet of soy protein isolate and adding sulfur-containing amino acids and/or potassium. 238 95

The case of a 7-year-old boy with the normotensive form of "chloride-shunt" syndrome is described. An unusual feature was the clinical presentation with lithiasis, caused by marked hypercalciuria of renal origin. The present studies were carried out to investigate the nature of the renal tubular defect. Indices for proximal and distal sodium chloride reabsorption were increased during hypotonic saline diuresis. Baseline sodium chloride excretion was low but increased above the range of control values after acute furosemide administration. Baseline potassium excretion was low, was not modified by the infusion of sodium chloride and increased significantly during infusions of sodium sulphate or sodium bicarbonate. Calcium excretion remained unchanged during sodium chloride, sodium sulphate or sodium bicarbonate infusions, but increased after furosemide administration. Nasal insufflation of 1-desamino-8-D-arginine-vasopressin induced both an increase in potassium excretion and a decrease in calcium and magnesium excretion. Plasma atrial natriuretic peptide was increased and was not significantly modified by infusion of hypertonic saline or acute administration of furosemide. These findings indicate that the primary renal abnormality appears to be an enhanced tubular reabsorption of sodium chloride, apparently present in the proximal tubule and the ascending loop of Henle. The associated presence of hypercalciuria also suggests a transport defect in the distal tubule. Decreased potassium excretion probably depends on a voltage-shunting defect in the cortical collecting tubule, which can be reversed by increasing the delivery of non-reabsorbable anions or by enhancing the conductance of the luminal membrane.(ABSTRACT TRUNCATED AT 250 WORDS)
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PMID:"Chloride-shunt" syndrome: an overlooked cause of renal hypercalciuria. 253 69

Idiopathic hypercalciuria, defined as the urinary excretion of more than 300 mg. calcium per day in men or more than 250 mg. calcium per day in women, or more than 4 mg. calcium per kg. per day, is observed in about 50 per cent of the patients with calcium oxalate/apatite nephrolithiasis and is one of the risk factors for stone formation. These patients do not exhibit hypercalcemia, elevated serum parathyroid hormone concentrations or urinary cyclic adenosine monophosphate excretion nor clinical evidence of sarcoidosis, other granulomas or a malignancy. Hypophosphatemia may be present. Augmented rates of intestinal absorption of dietary calcium account for most of the increments in urinary calcium. Serum 1,25-dihydroxyvitamin D concentrations are in the upper normal range or elevated among many patients and are normal but not suppressed in the others. Activation of 1,25-dihydroxyvitamin D formation may be secondary to hypophosphatemia or other, as yet undefined, factors. Since, 1,25-dihydroxyvitamin D apparently can up-regulate its own receptor, small increments in its synthesis and blood levels could amplify the effect of the hormone to stimulate intestinal calcium absorption. Calcium balances are slightly but significantly negative and urinary hydroxyproline excretion may be increased so that a generalized disorder of calcium homeostasis also involving bone may be present. Additional studies are required to determine the genetic basis for the occurrence of idiopathic hypercalciuria in families, the cause of greater expression of idiopathic hypercalciuria in men and whether environmental factors (high dietary sodium chloride, protein and purified carbohydrate intakes) contribute to the expression of idiopathic hypercalciuria. Although thiazide diuretics, inorganic phosphate, magnesium hydroxide and potassium citrate have provided effective therapy, prospective studies are needed to determine optimum therapy and the optimum duration of treatment.
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PMID:Idiopathic hypercalciuria. 264 29


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