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Query: UMLS:C0020500 (hyperoxaluria)
 912 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The part played by hyperoxaluria in the formation of calcium oxalate urinary calculi was studied in 153 patients who had each been diagnosed as having calcium oxalate urinary calculi on one or more occasions. Seventy-seven of the patients excreted normal amounts of calcium (less than 6.2 mmol/d), and 76 had hypercalciuria (excretion greater than or equal to 6.2 mmol/d); each group was divided into a further two groups depending on whether the oxalate concentration was above or below 0.16 mmol/l. Pure calcium oxalate stones were more common in patients whose calcium excretion was normal, and mixed calcium oxalate and phosphate stones were more common among hypercalciuric patients. Urinary concentrations/day of magnesium, citrate, and phosphorus were significantly lower in the two groups in which the oxalate concentrations were below 0.16 mmol/l than in a normal control group, and magnesium and phosphorus were significantly lower in the two groups in which oxalate concentrations were less than 0.16 mmol/l than in the two in which they were above that value. The concentration of citrate was also lower, but not significantly so. In addition, the pH of the urine in patients with mixed stones was significantly higher in all groups than when the stones were composed of pure calcium oxalate.
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PMID:The role of hyperoxaluria in the formation of calcium oxalate urinary calculi, and its association with other biochemical measurements. 223 98

Renal calcifications have been described in very low birth weight (VLBW) infants, and diuretic drug-associated hypercalciuria is believed to play a role in the pathogenesis of this lesion. Hyperoxaluria is an important cause of renal stone formation in children and adults. Because parenteral nutrition solutions contain the oxalate precursors ascorbate and glycine, the relationship between total parenteral nutrition administration and oxalate excretion in VLBW infants was examined. Administration of approximately 0.5 g of total parenteral nutrition protein per kilogram per day to VLBW infants was associated with an increased urinary oxalate concentration and an increased urinary oxalate to creatinine ratio, when compared with VLBW infants receiving a glucose and electrolyte solution. A further increase in urinary oxalate concentration and oxalate to creatinine ratio was noted when total parenteral nutrition protein was increased to approximately 1.5 g of protein per kilogram per day. In VLBW infants who receive total parenteral nutrition, elevated urinary oxalate concentrations may develop and may be a factor in the pathogenesis of nephrocalcinosis in these infants.
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PMID:Urinary oxalate excretion by very low birth weight infants receiving parenteral nutrition. 250 54

Farnolith (a dietary fibre preparation) was given to normal patients (n = 6) with absorptive hypercalciuria type I (n = 6) and to one patient with renal hypercalciuria. Farnolith binds calcium and reduces calcium absorption in the intestines. In normal subjects, the urine and serum parameters of calcium metabolism (total and ionized calcium, 1.25-dihydroxy-vitamin D) were unchanged. In absorptive hypercalciuria type I, a significant decrease in calcium excretion was achieved; oxalate excretion decreased as well. Low PTH values normalized; vitamin-D metabolites were not affected. In renal hypercalciuria, PTH and 1.25 DHCC were increased, whereas hypercalciuria persisted. Our investigations show that Farnolith is a reasonable treatment for absorptive hypercalciuria. Calcium homeostasis is rendered normal by Farnolith without producing secondary hyperoxaluria as sodium cellulose phosphate. Patients with primary renal calcium leakage and secondary hyperparathyroidism should not be treated with Farnolith.
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PMID:[Studies of calcium metabolism in normal persons and patients with hypercalciuria in relation to therapy with the dietary fiber preparation Farnolith]. 253 20

The morphological and infrared spectrophotometric analysis of the urinary stones of 300 patients have been reported in this article. Calculi are classified into six morphological types with their corresponding mineralogical natures. The type I (whewellite or C1) is pure in 18 p. cent of lithiasis, more often present in the center than on the surface, with hyperoxaluria in 81 p. cent. Calculi linked to piridoxilate intake (3 p. cent) have this composition. The type II (weddellite or C2) rarely pure, often associated with calcium phosphate are present in 47 p. cent of lithiasis, more often on the surface than in the center, and linked to hypercalciuria in 70 p. cent. The oxalates (C1 plus C2) are the most frequent components of calculi (75 p. cent). The type IIIa and IIIb (anhydrous and dehydrated uric acid) are pure in 8 p. cent, mixed in 6 p. cent; due to hyperuraturia in 55 p. cent, due to urinary acid pH in 60 p. cent. The type IVa (carbapatite) is pure in 5 p. cent, mixed in 26 p. cent, linked to hypercalciuria in 40 p. cent. The types IVb and IVc (struvite plus carbapatite) are present in 12 p. cent, due to urinary infection (90 p. cent), linked to proteus (70 p. cent). The type V (cystine) is rare, linked to hypercystinuria. The type VIa (1 p. cent) is made of proteins. The type VIb (2 p. cent) is composed of medications (triamterene, glafenine, antrafenine).
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PMID:[Correlation of the cause and composition of renal calculi. Value of morphologic and infrared analysis]. 264 1

The incidence and prevalence of urolithiasis in the Czechoslovak Socialist Republic is as high as in other countries of Central and Western Europe, and lower than in the Scandinavian countries. Apart from its high incidence, urolithiasis is characterized by its high tendency to recurrence. New knowledge of its pathogenesis helps to diagnose metabolic disorders responsible for increased excretion of concretion-producing substances and/or for deficiency in protective factors. In case of calcium oxalate lithiasis, with the highest incidence, attention is to be paid to its various forms of hypercalciuria, and, more recently, to moderate hyperoxaluria, and as regards protective factors, to magnesium, citrates, pyrophosphates and mucopolysaccharides. The determination of the type of metabolical disorder in patients with lithiasis enables to modify the diet and/or medication leading to causal prophylaxis against recurrence, i.e. metaphylaxis. At our Prague urological clinic, a consultation centre for lithiatic patients has been in operation since 1977. Long-term experience has shown that it has been successful especially in preventing recurrence or a in a substantial reduction in recurrence in 94% of the followed-up patients. Although the centre's activity is demanding both on the personnel and laboratory, even first sufferers from ilthiatic attacks should take advantage of it. At this early stage, such patients were found to have a metabolic disorders in 60%. In the past 7 years of treating nephrolithiasis and ureterolithiasis, new methods have been introduced which substantially improve the results and are less invasive than a classical operation. Among others, they comprise percutaneous endoscopic methods of disintegration and concrement extraction from the kidney and ureter, uteroscopy and extracorporeal shock-wave lithotripsy. It is to be expected that these methods will replace classical operations at a rate of 90%.
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PMID:[Urolithiasis. Review of present knowledge of epidemiology, pathogenesis, metaphylaxis and treatment]. 266 71

Hyperoxaluria and hypercalciuria are common features of renal calcium stone disease. The purpose of the present investigation was to examine the relationships between the intestinal absorption and the renal handling of oxalate and calcium in patients with idiopathic renal stone disease and in patients with enteric hyperoxaluria following jejunoileal bypass (JIB), in comparison with healthy controls. Hyperoxaluria was associated with a higher frequency of both stone episodes and stone operations than a lower urinary oxalate concentration. Patients with idiopathic stone disease showed increased intestinal uptake of both oxalate and calcium, which was probably of importance for their propensity to form calcium oxalate-containing stones. Hyperoxaluria in patients with JIB was found to be a result of hyperabsorption of oxalate, and these patients displayed altered oxalate kinetics with continued urinary excretion of orally administered 14C-oxalate for more than 48 hours. The prolonged excretion is assumed to be due to a prolonged absorption and/or an increased oxalate pool. Malabsorption of calcium and low fasting urinary calcium excretion in the JIB patients were associated with high tubular reabsorption of calcium, the latter presumably attributable to a compensatory increase in circulating parathyroid hormone (PTH). In most recurrent renal stone formers the urinary calcium concentration was increased, with an inverse relationship to serum PTH, indicating intestinal hyperabsorption of calcium. A subgroup of hypercalciuric patients showed increased urinary calcium due to reduced tubular reabsorption of calcium. It is suggested that this is a renal defect resulting in a compensatory rise in PTH. Two different mechanisms of similar prevalence might explain enhanced secretion of PTH in normocalcaemic stone disease, namely reduced calcium absorption and a renal defect in the form of reduced tubular reabsorption of calcium. Glycosaminoglycans efficiently inhibit calcium oxalate crystal growth by binding to the surface of calcium oxalate crystals. In this study the binding was dependent on ionic strength. Higher affinity to the crystals may be the reason why highly charged glycosaminoglycans were more efficient inhibitors of calcium oxalate crystal growth. A calcium-containing organic marine hydrocolloid with the capacity to bind oxalate in vitro was shown to reduce enteric hyperoxaluria. In addition to biochemical effects considerable improvements in diarrhoeal symptoms were reported.
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PMID:Oxalate metabolism in renal stone disease with special reference to calcium metabolism and intestinal absorption. 266 21

The mechanism of stone formation in the urinary tract is reviewed. Diet, urinary tract infection and metabolic disorders account for the different epidemiological patterns of stone formation. The diagnosis and management of renal tract calculi are discussed. Calcium stones are associated with hypercalciuria, urine acidification defects, the use of furosemide in premature babies, hypercalcaemia, hyperoxaluria, hyperuricosuria, an alkaline urine and hypocitraturia. Uric acid stones occur in acid urine, from increased purine synthesis with lympho- or myeloproliferative disorders or from several inborn errors of purine metabolism which can also cause xanthine or dihydroxyadenine stones. Cystinuria, inherited as an autosomal recessive disorder is best treated with a low sodium diet, a fluid intake exceeding 40 ml/kg per day maintaining urine pH between 7.5 and 8 and, if necessary, with oral penicillamine. Oxalate stones occur in relation to diet, bowel disease and primary inherited defects in oxalate metabolism. Urinary tract infection causing struvite and carbonate apatite formation is the commonest cause of stones in Europe.
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PMID:Urolithiasis in children: current medical management. 270 15

Oxalate excretion was measured in healthy subjects and idiopathic calcium stone-formers on dietary regimens which differed in the type and amount of protein allowed; 24-h urine collections were obtained from 41 practising vegetarians and 40 normal persons on a free, mixed, "mediterranean" diet. Twenty idiopathic calcium stone-formers were also studied while on two low calcium, low oxalate diets which differed in that animal protein was high in one and restricted in the other. Vegetarians had higher urinary oxalate levels than controls and although the calcium levels were markedly lower, urinary saturation with calcium/oxalate was significantly higher. This mild hypercalciuria was interpreted as being secondary to both a higher intake and increased fractional intestinal absorption of oxalate. Changing calcium stone-formers from a high to a low animal protein intake produced a significant decrease in calcium excretion but there was no variation in urinary oxalate. As a result, the decrease in calcium oxalate saturation was only marginal and not significant. It was concluded that dietary animal protein has a minimal effect on oxalate excretion. Mild hyperoxaluria of idiopathic calcium stone disease is likely to be intestinal in origin. Calcium stone-formers should be advised to avoid an excess of animal protein but the risks of a vegetable-rich diet should also be borne in mind.
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PMID:Effect of animal and vegetable protein intake on oxalate excretion in idiopathic calcium stone disease. 271 14

Metabolic disorders are the most frequent risk factor for the development of urolithiasis. They are manigenic substances or deficiency of inhibitors of crystalgenic substances or deficiency of inhibitors of crystallization and aggregation. The authors use for their diagnosis a modification of Pak's procedure. It involves examination of 24-hour urine with the patient on a low-calcium diet, supplemented by urine examination on fasting and after a 1000 mg calcium load. The procedure includes also examination of serum and bacteriological examination of urine. A total of 93% of patients with calcium lithiasis had a metabolic disorder, 42% suffered from idiopathic hypercalciuria, 32% from hyperuricosuria, 19% from hyperoxaluria, 15% from magnesium deficiency and 38% from hypocitraturia. On the other hand, patients with uric acid lithiasis had a detectable metabolic disorder only in 62%. Active detection of metabolic disorders is essential for the introduction of effective, specific metaphylaxis of urolithiasis.
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PMID:[Detection of metabolic disorders as a cause of urolithiasis in clinical practice]. 272 Jul 28

Twenty-four-hour urinary excretion of calcium, oxalic acid, inorganic phosphorus, magnesium and citric acid was examined in fifty-nine stone formers with bladder stones. Hypercalciuria and hyperoxaluria were present in 18.6% and 44.1%, respectively, while 11.9% of patients had both abnormalities. Hypomagnesuria and hypocitraturia were present in 67.8% and 69.5%, respectively, while 45.7% had both of these abnormalities. Normal urine chemistry in respect of parameters studied was observed only in 1.7% of cases. In 15.2% one risk factor was present, while 83.1% had two or more risk factors. "Path" analysis of the urinary parameters directly related to calcium lithiasis showed that magnesium and oxalic acid have substantial influence on calcium excretion, whereas citric acid had none. The influence of phosphorus did not provide any consistent trend.
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PMID:Interdependence of urinary factors in calcareous bladder stone patients. 274 86


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