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

On the basis of routine clinical and laboratory investigations, one or more probable or possible causes of stone formation were established in 27% of upper urinary tract and 98% of bladder stone patients. In the upper urinary tract, causes were usually found for triple phosphate and pure calcium phosphate stones and rarely for pure calcium oxalate stones. Except for cystine stones and largely for triple phosphate stones there was no definite correlation between the composition of stone and causes. Uric acid and urate stones were often not associated with obvious causes, but their demonstration should lead to further investigations. In a small group of recurrent calcium stone formers examined for hypercalciuria, hyperoxaluria, hyperuricosuria, and renal tubular acidosis, positive findings were noted for 65%, but there was no consistent correlation between these findings and the types of stone. Stone analysis is most useful in so far as it identifies or excludes triple phosphate, cystine, and uric acid/urate stones. This may be done by simple chemical analysis. Certain rare components may, however, be overlooked, as will details of stone structure, unless crystallographic methods are employed.
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PMID:Correlation between causes and composition of urinary stones. 634 79

Because of mounting evidence of precipitation of calcium oxalate in the soft tissues of patients with end-stage renal disease (ESRD) on maintenance hemodialysis, the plasma oxalate concentrations and calculated dialysis removal of oxalate were studied in seven patients without evidence of either primary or absorption hyperoxaluria prior to ESRD. A reversed-phase high-pressure liquid chromatographic method was developed to quantitate serum oxalate. Mean value +/- SE in four healthy controls was 28 +/- 5 mumol/L, and in the seven patients it was 187 +/- 15 mumol/L predialysis and 89 +/- 11 mumol/L postdialysis. Oxalate deposition in the soft tissues of ESRD patients is the consequence of sustained hyperoxalemia. Oxalate removal by dialysis was calculated from the four-hour oxalate clearance. Since the ionic radii of phosphate and oxalate are similar, total oxalate clearance was calculated midpoint of dialysis. Mean oxalate removal/dialysis was 3.01 +/- 0.283 mmol. On a daily basis this value was 1.645 +/- 0.155 mmol, which is about threefold the normal oxalate excretion rate. It is not significantly different from the excretion rate in absorption oxalurias but is less than that in primary hyperoxaluria. Therefore, it is concluded that hyperoxalemia in ESRD results from loss of renal excretion, failure of hemodialysis to remove enough oxalate to maintain a normal serum concentration, and increased intestinal absorption of oxalate and/or increased endogenous production.
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PMID:Oxalate removal by hemodialysis in end-stage renal disease. 647 42

The pathophysiologic consequences of renal function impairment and chronic renal failure among others result from the loss of excretory and regulatory functions of the kidneys. The role of the exchange of cellular hydrogen ions of tubular fluid in the reabsorption of bicarbonate and in the urinary excretion of titratable acid and ammonia (acid-base regulation) is outlined. The effects of decreased glomerular filtration rate on calcium and phosphorus homeostasis are discussed. De novo urolithiasis in these patients is uncommon. However, it is well recognized that they may form matrix stones with calcium oxalate inclusions. Of greater significance is the prophylaxis in those patients, in whom urolithiasis has been the cause of chronic renal failure. In these patients it is of importance to modify the drug dosage or to abandon the prophylaxis when it interferes with the metabolic changes of renal function impairment. Some agents require no modification, others minor or major modifications. Some are even contraindicated. Hazards of stone prophylaxis in chronic renal failure: Acidification - cave metabolic acidosis! Cave RTA! Antibiotic agents - special rules to prevent accumulation. Thiazides - contraindicated! Hypokalemia; hyperuricemia; cave HPT! Triamterene - contraindicated! Acetazolamide (cystinuria) - contraindicated. Spironolactone - contraindicated. Sodium-cellulose-phosphate - Hyperoxaluria, hypomagnesiuria , hyperphosphatemia, cave HPT. Orthophosphate - cave urinary infection, cave poor renal function, cave obstruction. Allopurinol - dose reduction advisable. Brenzbromaron - contraindicated.
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PMID:[Prevention of calculus recurrence in impaired kidney function]. 653 25

Hyperoxaluria, alone or associated with hypercalciuria, has been detected in 69 of 450 patients with recurrent stones (15.3 per cent). The 3 main findings associated with hyperoxaluria were 1) oxalate hyperabsorption, 2) hyperoxalemia and 3) increased or decreased oxalate clearance. Correction of oxalate hyperabsorption by administration of diethylaminoethanol cellulose showed good results through a 5-year followup. Succinimide, given to the hyperoxalemic group, and a combination of phosphate and magnesium, given to the group with altered clearances, showed poorer results.
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PMID:Effect of a 5-year treatment program in patients with hyperoxaluric stones. 663 5

The authors report on metabolic studies on growing domestic pigs with resected ilea on a diet supplemented with oxalic acid and calcium. The content of calcium, magnesium and phosphate in the kidneys and ribs was determined and their excretion in urine was measured. The supplement of oxalic acid in the diet mainly affects the calcium content of the kidneys. It is also likely that oxalic acid inhibits the accumulation of calcium in the skeleton. Hyperoxaluria and hyperphosphaturia were established, whereas significantly less calcium and magnesium were excreted. The results of these animal experiments confirm previous clinical findings.
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PMID:[Clinical and animal experiment studies on the pathogenetic significance of small intestine diseases and resections for urolithiasis]. 663 70

Metabolic studies include certain routine investigations but which may be more or less limited or extended according to the individual case on the basis of its severity and the chemical nature of calculi. These studies are based upon the following data: analysis of one or more stones, aided and guided by methodical macroscopic examination; urine microscopy; study of urine pH which should be done by the patient himself on several samples during the 24-hour period; blood and urine calcium/phosphate balance, without omitting the measurement of urinary urea which provides information concerning protein intake and indicates its influence; oxalate balance studies and hyperoxaluria are correlated with cases of lithiasis when stones contain only calcium oxalate or a mixture of oxalate and calcium phosphate; uric acid balance, where once again the measurement of urinary urea is of fundamental importance and shows that all cases of hyperuricuria are related to a diet excessively rich in meat; urinary cystine levels with the need for a Brand reaction almost routinely in all lithiasis sufferers; electrolyte studies which may reveal a renal tubular acidosis syndrome, in fact rare; and, finally, in certain cases a magnesium balance may show a decreased erythrocyte magnesium.
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PMID:[Remarks on the metabolic evaluation of renal lithiasis]. 672 70

During 5 years, between 1978 and 1982, 40 patients (22 male, 18 female) aged 1 to 17 years presented with kidney stones at the Erlangen University Children's Hospital. Stone analysis showed calcium oxalate in 61%, calcium phosphate respectively magnesiumammonium phosphate in 33% and cystine in 6%. Calcium phosphate/ magnesiumammonium phosphate stone bearers were most frequently found in the first 5 years of age and showed more often urinary tract malformations, staghorn renal calculi, urinary tract infections and a higher urinary pH. Calcium oxalate stone bearers were more frequently found in patients of school age and had more often relatives with nephrolithiasis. In the group of calcium oxalate stones hypercalciuria, hyperoxaluria and hyperuricosuria were most frequently observed.
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PMID:[Clinical and chemical factors in kidney calculus formation in childhood. An analysis of 40 patients]. 672 88

The electron microscopic investigation of the renal medulla in calcium oxalate stone patients has shown the frequent occurrence of globoid microconcrements in the basal laminae of the collecting ducts and of the thin limbs in Henle's loop. They have a concentrically layered structure, the diameter is usually below 1.5 microns, rarely more than 3 microns. Some of these objects were also seen in the interstitial connective tissue. Tissue of stone-free patients exhibited either no or only few such microconcrements which were usually located in the interstitial space. Histochemical tests and energy dispersive microprobe analysis suggest that calcium phosphate and acid mucopolysaccharides are principal components of the microconcrements. There are indications that some microconcrements might be expelled from the basal laminae into the urinary space and may form agglomerations. They might then furnish nuclei for heterogeneous crystallization especially in cases without hypercalciuria or hyperoxaluria.
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PMID:[Concentrically layered microconcrements in the renal medulla of nephrolithiasis patients. A contribution to the renal stone pathogenesis (author's transl)]. 720 99

Oral sodium cellulose phosphate, an inhibitor of intestinal calcium absorption, may reduce urinary magnesium, increase urinary oxalate, and have a limited hypocalciuric action or cause negative calcium balance in the absence of increased calcium absorption or in the presence of renal calcium "leak". To overcome these potential complications, we have taken the following precautions: oral magnesium supplements were given, a moderate oxalate restriction was imposed, a modest dose of sodium cellulose phosphate was used (usually 10 g per day), and only patients with documented absorptive hypercalciuria were treated. During a cumulative treatment period of 42.8 years, 18 patients with recurrent calcium nephrolithiasis showed a sustained reduction in urinary calcium, without developing consistent or substantial reduction in urinary magnesium, hyperoxaluria, hyperparathyroidism, or reduced bone density, Urinary saturation (relative saturation ratio) of calcium oxalate and brushite typically decreased. Remission of stone disease was found in 78 per cent of patients. We conclude that sodium cellulose phosphate is a useful drug for absorptive hypercalciuria when used appropriately.
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PMID:A cautious use of sodium cellulose phosphate in the management of calcium nephrolithiasis. 729 89

Clinical and biochemical data were obtained from 50 patients in whom stones form and 20 controls to set up and test a screening procedure for detecting metabolic abnormalities related to the formation of urinary calculi and to provide a preliminary estimate of the frequency of these disorders in our area. A comparison between patients in whom stones form and controls in terms of the quantitative biochemical parameters evaluated (serum calcium, uric acid and inorganic phosphate, and urine calcium, uric acid, inorganic phosphate, oxalic acid, xanthine and alpha-amino-nitrogen) showed a significant difference only with respect to excretion of urinary oxalate by adults, which was higher in patients in whom stones form. Metabolic disorders were detected in 15 adult patients with stones. Of these patients 9 had isolated hyperoxaluria, 3 had incomplete renal tubular acidosis, 1 had idiopathic hypercalciuria, 1 had heterozygous cystinuria and 1 had idiopathic hypercalciuria associated with heterozygous cystinuria. These results suggest a high frequency of metabolic abnormalities in patients in whom stones form in our area, so that the wider use of the screening used here may benefit a large number of patients with preventive and therapeutic measures.
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PMID:Metabolic factors in urolithiasis: a study in Brazil. 742 May 93


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