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

Primary hyperoxaluria (PH) is a severe inherited disease induced by an enzymatic deficiency responsible for high endogenous production of oxalate. Oxalate ions are excreted by the kidney where they can form an insoluble salt with calcium ions, thus inducing urinary stones, crystal deposition in the tubular lumen and renal parenchyma leading to nephrocalcinosis and renal failure. Eighty-seven calculi from 63 PH patients with primary hyperoxaluria were analyzed and compared to 24,130 calculi from unselected consecutive stone formers referred to our laboratory between January 1977 and December 1996. All stones were analyzed according to a protocol including morphological examination of both surface and cross-section, and sequential infrared identification of the crystalline phases. A typical aspect of both surface and section corresponding to morphological type Ic according to our proposed classification (Daudon et al. Scanning Microsc 1993, 7:1081-1106) was observed in all patients but two whereas only two type Ic stones were observed among patients without primary hyperoxaluria. The latter two patients suffered from severe inflammatory bowel disease and developed heavy hyperoxaluria following extensive ileal resection. We conclude that evidence of type Ic morphology is a simple, cheap and fast tool to detect diseases with heavy hyperoxaluria such as primary hyperoxaluria.
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PMID:Unusual morphology of calcium oxalate calculi in primary hyperoxaluria. 960 12

Patients with cystic fibrosis (CF) have an increased risk of urolithiasis/nephrocalcinosis. To determine potential mechanisms responsible, we studied the urinary excretion of lithogenic and stone-inhibitory substances and calculated the urinary saturation for calcium-oxalate (CaOx), brushite (CaHPO4), and uric acid (UA). We examined 24-h urines in 63 patients with CF (34 female, 29 male) aged 5 months to 36 years. Renal ultrasonography was performed at the time of urine collection. Hyperoxaluria was found in 25 patients (range 0.51-1.71 mmol/1.73 m2 per 24 h). Urinary Ca was increased in 13 patients (4.1-8.22 mg/kg per 24 h). Hyperuricosuria was found in 16 patients (5.2-18.0 mmol/1.73 m2 per 24 h) and hypocitraturia in 14 patients (0.07-1.14 mmol/1.73 m2 per 24 h). CaOx saturation was elevated in 26 patients, related to hyperoxaluria in 19 patients. CaHPO4 saturation was increased in 19 patients and UA saturation in 11 patients. Urolithiasis in situ was diagnosed in 1 patient; 3 patients previously had renal stones; 4 patients had present nephrocalcinosis. Elevated excretion of lithogenic substances and urinary supersaturation might lead to the higher risk of urolithiasis/nephrocalcinosis in patients with CF.
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PMID:Urinary excretion substances in patients with cystic fibrosis: risk of urolithiasis? 965 56

Urolithiasis is uncommon in adolescence and rare in early childhood. In pediatric populations, congenital urinary tract anomalies associated with stasis and infection, idiopathic urolithiasis (adolescents), and nephrocalcinosis (premature infants) account for the majority of urolithiasis patients. Inborn errors of metabolism, such as the primary hyperoxalurias, are rare causes of urolithiasis in childhood. We report six children (mean age at symptom onset 1.3 years; range 0.32-4.1 years) with moderate hyperoxaluria (mean 1.10 +/- 0.58 mmoL/1.73m2 per day; range 0.69-2.19 mmoL/1.73m2 per day). Urolithiasis was present in four. Stones from two children were comprised of calcium oxalate dihydrate. Calcium oxalate crystalluria was seen in two of the patients. Findings included a mean urine calcium concentration of 6.61 +/- 2.28 mg/kg per day, urine citrate of 925.5 +/- 291.29 mg/g of creatinine per day, and mean renal clearance of 99.83 +/- 23.27 mL/min. All children were born full term, none was receiving diuretics, and none had recurrent urinary tract infections. Secondary causes of hyperoxaluria, including dietary oxalate excess, pyridoxine deficiency, and malabsorption, were excluded. Urine glycolate and glycerate were normal in all patients. In one hyperoxaluric member of each sibship, hepatic alanine-glyoxylate aminotransferase and D-glycerate dehydrogenase/glyoxylate reductase activity were normal. The clinical and biochemical features of these children are unlike those in previously recognized hyperoxaluric states. Thus, our description of a separate hyperoxaluric entity, referred to as unclassified hyperoxaluria.
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PMID:Hyperoxaluria and urolithiasis in young children: an atypical presentation. 1060 14

We report the case of a 10-year-old girl who received a cadaveric kidney transplant for oxalosis after a period of 12 months on hemodialysis. The donor was a 6-year-old child. Cold ischemia was four hours. Diuresis occurred immediately in the operating room. Mean daily diuresis was maintained at 8 liters: first by i.v. perfusion, then by nocturnal continuous nasogastric hydration. In addition to the usual immunosuppressive drugs, she received pyridoxine, sodium citrate, phosphate, hydrochlorothiazide and magnesium. Daily hemodialysis was performed from Day 1 to Day 9 and four additional sessions every other day. The postoperative course was satisfactory. Oxaluria was elevated initially at 1074 mg/24 h (normal < 50 mg/24 h). One year later, mean daily diuresis is still 8 liters, renal function is normal and oxaluria is at 296 mg/24 h. Repeated graft sonography showed no nephrocalcinosis, but mild oxalate deposits are noted on renal biopsy. Isolated renal transplantation was successful in our patient. It allowed us to stop hemodialysis and to avoid extra-renal accumulation of oxalate. Despite this success, we are convinced that long term prognosis is uncertain and liver transplantation should be realized to correct definitely the biochemical defect.
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PMID:Dilemma of oxalosis in end stage renal failure: isolated kidney allograft or hemodialysis. 1088 38

In primary hyperoxaluria type 1 (PH 1), deficiency or mistargeting of hepatic alanine glyoxylate aminotransferase (AGT) results in over-production of oxalate and hyperoxaluria, leading to nephrocalcinosis and development of end-stage renal disease (ESRD) in the majority of patients. Renal transplantation (Tx) alone carries a high risk of disease recurrence as the metabolic defect is not cured. Therefore, combined liver/kidney Tx is recommended for patients with ESRD. An alternative approach is to cure PH 1 by pre-emptive isolated liver Tx (PLTx) before ESRD has occurred, but this approach has been carried out only occasionally and there are no uniformly accepted recommendations concerning the timing of this procedure. We report follow-up 3-5.7 yr after performing successful PLTx in four children (at the age of 3-9 yrs) with PH 1 prior to the occurrence of ESRD (glomerular filtration rate [GFR] range 27-98 mL/min/1.73 m2). There was no mortality or long-term morbidity associated with the Tx procedure. Plasma and urinary oxalate levels normalized rapidly within 4 weeks, and renal function did not deteriorate under immunosuppression, even in one patient with advanced chronic renal failure (GFR 27 mL/min/1.73 m2) who showed a stable course for more than 5.7 yrs. Although treatment must be individualized in this severe metabolic disorder, and PLTx has to be regarded as an invasive procedure, we consider that PLTx should be offered and considered early in the course of PH 1. PLTx cures the metabolic defect in PH 1 and can help to prevent, or at least delay, the progression to ESRD and systemic oxalosis.
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PMID:Long-term results of pre-emptive liver transplantation in primary hyperoxaluria type 1. 1093 16

To determine whether an "atherogenic" diet (excess of cholesterol and neutral fat) induces pathological calcification in various organs, including the kidney, and abnormal oxalate metabolism, 24 male Sprague-Dawley rats were fed either normal lab chow (controls, n = 12) or the cholesterol- and fat-rich experimental diet (CH-F, n = 12) for 111 +/- 3 days. CH-F rats developed dyslipidemia [high blood levels of triglycerides, total, low-density lipoprotein (LDL)-, very low-density lipoprotein (VLDL)-, high-density lipoprotein (HDL)-bound cholesterol, total phospholipids], elevated serum total alkaline phosphatase and lactate dehydrogenase (LDH) levels, in the absence of changes in overall renal function, extracellular mineral homeostasis [serum protein-corrected total calcium, magnesium, parathyroid hormone (PTH), 1,25-dihydroxyvitamin D (1,25(OH)2D)], plasma glycolate and oxalate levels. There was a redistribution of bone calcium and enhanced exchange of this within the extraosseous space, which was accompanied by significant bone calcium loss, but normal bone histomorphometry. Liver oxalate levels, if expressed per unit of defatted (DF) dry liver, were three times higher than in the controls. Urinary glycolate, oxalate, calcium and total protein excretion levels were elevated, the latter showing an excess of proteins > 100 kD and a deficit of proteins > 30-50 kD. Urinary calcium oxalate supersaturation was increased, and calcium phosphate supersaturation was unchanged. There were dramatically increased (by number, circumference, and area) renal calcium phosphate calcifications in the cortico-medullary region, but calcium oxalate deposits were not detectable. Electron microscopy (EM) and elemental analysis revealed intratubular calcium phosphate, apparently needle-like hydroxyapatite. Immunohistochemistry of renal tissue calcifications revealed co-localization of phospholipids and calcium phosphate. It is concluded that rats fed the CH-F diet exhibited: (1) a spectrum of metabolic abnormalities, the more prominent being dyslipidemia, hyperoxaluria, hypercalciuria, dysproteinuria, loss of bone calcium, and calcium phosphate nephrocalcinosis (NC); and (2) an interaction between calcium phosphate and phospholipids at the kidney level. The biological significance of these findings for the etiology of idiopathic calcium urolithiasis in humans is uncertain, but the presented animal model may be helpful when designing clinical studies.
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PMID:Nephrocalcinosis and hyperlipidemia in rats fed a cholesterol- and fat-rich diet: association with hyperoxaluria, altered kidney and bone minerals, and renal tissue phospholipid-calcium interaction. 1122 20

The primary hyperoxalurias (PH1 and PH2) are rare defects of oxalate overproduction. There are only 24 reported cases of PH2, which is characterized by raised urine oxalate and L-glycerate. We describe 13 previously unreported children with PH2, representing the largest single-centre cohort in the world. DNA samples were tested for a common mutation and four other documented mutations in the gene encoding the enzyme glyoxylate reductase/hydroxypyruvate reductase (GRHPR). Two of the five kindred showed homozygosity for two different mutations in the GRHPR gene. The genetic defect was not identified in the other three families. The median age at diagnosis of PH2 was 1.7 years. Five children presented with nephrolithiasis between 0.8 and 9 years. Haematuria was common, but urinary tract infection and nephrocalcinosis were not. All had normal renal function at diagnosis, and only 1 patient had a significant decline in glomerular filtration rate. We conclude that all children with nephrolithiasis secondary to hyperoxaluria should have urinary glycerate measured, as PH2 may be more prevalent than currently estimated. DNA mutational analysis may be useful in supporting the diagnosis.
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PMID:Primary hyperoxaluria type 2 in children. 1218 64

Annual incidences of kidney stones are about 0.1-0.4% of the population, and lifetime prevalences in the USA and Europe range between 8 and 15%. Kidney stones occur more frequently with increasing age and among men. Within ten years, the disease usually recurs in more than 50% of patients. Nowadays, about 85% of all kidney stones contain calcium salts (calcium oxalate and/or calcium phosphate) as their main crystalline components. Because human urine is commonly supersaturated with respect to calcium salts as well as to uric acid, crystalluria is very common, i.e. healthy people excrete up to ten millions of microcrystals every day. Recurrent stone formers appear to excrete lower amounts or structurally defective forms of crystallization inhibitors which allows for the formation of large crystal aggregates as precursors of stones. Alternatively, crystal adhesion to urothelial surfaces may be enhanced in stone formers. Medical treatment of renal colic is based on nonsteroidal antiinflammatory drugs, because prostaglandins appear to play a crucial role in the pathophysiology of pain during ureteral obstruction. In addition, centrally acting analgesics such as pethidine-HCl may be required in many cases. The administration of high amounts (3-4 liters/day) of intravenous fluids should be abandoned, since it may raise intraureteral pressure whereby pain increases and kidney pelvis or fornices may rupture. All first-stone formers should undergo a simple basic evaluation, including stone analysis (x-ray diffraction or infrared spectrometry), serum values of ionized calcium (alternatively: total calcium and albumin) and creatinine, urinalysis and repeated measurements of fasting urine pH in order to detect urinary acidification disorders or low urine pH. In high-risk patients with as first stone episode (i.e. strongly positive family history, inflammatory bowel disease, short-bowel syndrome, nephrocalcinosis, bilateral stones, hypercalcemia, renal tubular acidosis, airline pilots) as well as in all recurrent stone formers, an extended metabolic evaluation should be performed. Two 24-hurines should be collected on free-choice diet not prior to three months after stone passage or urological intervention. Analysis includes measurements of volume, creatinine, calcium, oxalate, uric acid and citrate; sodium and urea as markers of salt and protein consumption are optional but clinically very helpful. Since hypercalciuria is of much less importance than increases in urinary oxalate, therapeutic efforts should primarily focus on lowering urinary oxalate excretion. Sufficient calcium intake, i.e. 1200 mg per day, is crucial, because it allows for binding of oxalate at the intestinal level whereby increases of urinary oxalate (reciprocal hyperoxaluria) can be avoided. Excess intake of flesh protein (meat, fish, poultry) is lithogenic since it increases urinary calcium, oxalate and uric acid, and lower citrate. On the other hand, a diet rich in alkali (vegetables, fruit) is associated with a lower risk of stone formation. A "common sense diet" containing sufficient amounts of fluids, 1200 mg of calcium per day and reduced amounts of flesh protein as well as salt is able to reduce the 5-year stone recurrence rate in calcium stone formers by 50%. The scientific evidence for drug treatment (thiazides, alkali citrate) is rather poor: the most widely quoted randomized thiazide trial included only 42 patients of whom 36% left the protocol prematurely, whereas 36-48% of patients included in three randomized studies with alkali citrate suffered from undesirable side-effects; nevertheless, citrate therapy reduced the stone recurrence rate by 38%, compared with 22% in patients on placebo treatment (p < 0.0005).
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PMID:[Pathophysiology, diagnosis and conservative therapy in calcium kidney calculi]. 1264 86

Primary hyperoxaluria (PH) is a heterogeneous disease with a variable age of onset and a variable progression into kidney failure. Early diagnosis is mandatory to avoid the damaging effects of systemic calcium oxalate deposition. In 1997, we initiated a nationwide survey of American nephrologists to ascertain epidemiological data and current practices. PH was reported in only 102 patients, with PH I in 79 and PH II in 9; 14 patients were not classified. Most patients were Caucasian (84%). Main symptoms at diagnosis were urolithiasis (54.4%) and nephrocalcinosis (30%). A significant delay of diagnosis was seen in 42% of patients and 30% of patients were diagnosed only at end-stage renal disease (ESRD). Diagnosis was usually based on history and urinary oxalate excretion. Glycolate and l-glyceric acid excretion were rarely determined. To determine the enzyme defect, a liver biopsy was performed in 40%. Even at ESRD, only 56% of patients received an adequate diagnostic work-up. Half of the patients showed 'good' or 'fair' pyridoxine sensitivity. In addition to B(6), most patients received either citrate or orthophosphate. Kidney transplantation (KTx) failed in 19 of 32 transplants ( n=27 patients) and was due to recurrent oxalosis in 8 transplants. Liver Tx was performed after KTx in 5 patients (1 patient died). Combined liver-kidney Tx in 21 patients (in 9 patients after failure of KTx) achieved good organ function in 13 patients; 7 patients, however, died shortly after transplantation. In conclusion, the time between first symptom and diagnosis of PH must be minimized, and the diagnostic procedures have to be improved. The cases of unclassified hyperoxaluria suggest the possibility of additional type(s) of PH. As isolated KTx failed in 59% of patients, combined liver-kidney Tx seems to be the better choice in place of isolated KTx as the primary transplant procedure.
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PMID:A United States survey on diagnosis, treatment, and outcome of primary hyperoxaluria. 1292 Jun 26

A crucial role for cell-crystal interactions in the development of urolithiasis (UL) and nephrocalcinosis (NC) was previously observed in experiments with different cell lines mimicking renal epithelial cells. It was found that such cell-crystal interactions lead to tubular damage and/or or dysfunction. To find further proof for these observations, we measured the urinary N-acetyl-beta- d-glucosaminidase (NAG) excretion, a marker of proximal tubular damage, in children with UL or NC and in children with an increased risk of UL. We enrolled 142 children aged 4-16 years (mean 9.67+/-3.40 years), with 50 children having UL, 30 children with a history of UL (ULH), 20 patients with NC, 34 children with secondary hyperoxaluria (HyOx), and 8 children with idiopathic hypercalciuria (HC). Normal urinary NAG/Cr values were determined in a group of 70 healthy children aged 4-16 years (mean 10.06+/-3.97 years). The urinary NAG activity was measured using a colorimetric method and the results were expressed as molar creatinine (Cr) ratios. The highest median NAG/Cr ratios were found in children with UL plus hematuria (0.72 U/mM) and in children with UL (0.67 U/mM) or NC (0.48 U/mM), which were all significantly higher than those in controls (0.28 U/mmol, P<0.001 and P<0.05). The NAG/Cr ratios were increased above the upper normal reference interval of 0.63 U/mM (95th percentile) in 28 of 50 (56%) children with UL and in 9 of 20 (45%) children with NC. Although the ULH group also had significantly higher median NAG/Cr ratios (0.36 U/mM) compared with controls, the NAG/Cr ratio was only elevated in 4 of 30 (13%) patients. NAG values in children with secondary HyOx or HC were not different from controls. No correlation was found between the NAG/Cr ratios and the urinary excretion of oxalate or calcium. In conclusion, UL or NC may result in proximal tubular injury, which is rather the consequence of disease activity and of the mechanical influence of calculi, than of the metabolic background. The mechanism of cell damage in these conditions however, seems to be complex. Neither HyOx nor HC alone were sufficient to induce severe tubular damage expressed as an increase in NAG excretion in our patients.
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PMID:Urinary NAG in children with urolithiasis, nephrocalcinosis, or risk of urolithiasis. 1292 Jun 32


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