Gene/Protein Disease Symptom Drug Enzyme Compound
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Query: UMLS:C0451641 (urolithiasis)
 3,973 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

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

Secondary hyperoxaluria is due either to increased intestinal oxalate absorption or to excessive dietary oxalate intake. Certain intestinal diseases like short bowel syndrome, chronic inflammatory bowel disease or cystic fibrosis and other malabsorption syndromes are known to increase the risk of secondary hyperoxaluria. Although the urinary oxalate excretion is usually lower than in primary hyperoxaluria, it may still lead to significant morbidity by recurrent urolithiasis or progressive nephrocalcinosis. A clear distinction between primary and secondary hyperoxalurias is important. As correct classification may be difficult, appropriate diagnostic tools are needed to delineate the metabolic background as a basis for optimal treatment. We developed an individual approach for the evaluation of patients with suspected secondary hyperoxaluria. First, 24 h urines are examined repeatedly for lithogenic (e.g. calcium, oxalate, uric acid) and stone-inhibitory (e.g. citrate, magnesium) substances, and the patients are asked to fill in a dietary survey form. Urinary saturation is calculated using the computer based program EQUIL2, and the BONN-Risk-index is determined. The measurement of plasma oxalate and of urinary glycolate helps to distinguish between primary and secondary hyperoxalurias. If secondary hyperoxaluria is suspected, the stool is examined for Oxalobacter formigenes, an intestinal oxalate degrading bacterium, as lack or absence may lead to increased intestinal oxalate absorption. The last diagnostic step is to study the intestinal oxalate absorption using [13C2]oxalate. Depending on the results, various therapeutic options are available: 1) a diet low in oxalate, but normal or high in calcium, 2) a high fluid intake (>1.5 L/m2/d), 3) medications to increase the urinary solubility, 4) specific therapeutic measures in patients with malabsorption syndromes, depending on the underlying pathology, and 5) intestinal recolonization of Oxalobacter formigenes or the treatment with other oxalate degrading bacteria.
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PMID:Diagnostic and therapeutic approaches in patients with secondary hyperoxaluria. 1295 11

Urolithiasis is rare in children. Contrary to adults, the great majority have an identifiable predisposing cause, metabolic, infectious or structural. Those causes often coexist. A complete assessment for all these factors is thus always indicated. Symptoms are often non-specific. The diagnosis must be considered in case of intense abdominal pain. The majority of urolithiasis in children are radiopaque. Ultrasonography looks for impairment of the urinary flow, signs of underlying uropathy and nephrocalcinosis. Non contrast spiral CT scan is more sensitive for soft stones and ureteral stones. Morphoconstitutional analysis of the calculi provides essential information on etiology, limitating further metabolic evaluation. If the stone seems unlikely to pass spontaneously, extra-corporeal shock wave lithotripsy is the first-line treatment for the great majority of children. Recurrence is common. Long-term medical treatment is essential. The first step is to maintain a high urine output by increasing water intake. Long-term prognosis is dependent on early diagnosis and on compliance to treatment.
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PMID:[Urolithiasis in children and adolescents]. 1518 33

Primary hyperoxaluria type I is a rare inborn error of metabolism caused by a deficiency of a liver-specific peroxisomal enzyme. It manifests by increased oxalate production that ultimately results in kidney failure, due to urolithiasis and nephrocalcinosis, and finally induces systemic oxalosis and risk of premature death. Primary hyperoxaluria type 2 is mainly responsible of urolithiasis. Enteric hyperoxaluria is a commonly seen adverse event of Crohn disease or after extensive intestinal resection. These affections represent the main etiologies of massive hyperoxaluria. If not recognized very soon and adequately treated, these conditions can progress rapidly to end stage renal failure.
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PMID:[Massive hyperoxaluria]. 1549 71

Calcium-oxalate crystal deposition in kidney transplant biopsy specimen led us to investigate the impact of calcineurin inhibitor treatment on urinary excretion of lithogenic and stone inhibitory substances in 53 children after successful kidney transplantation (KTx) receiving cyclosporine A (CsA) or tacrolimus. We compared the values obtained with those of 12 patients with recurrent nephrotic syndrome under CsA and of 6 patients with Rasmussen encephalitis (RE) under tacrolimus therapy. Renal ultrasound examinations were repeatedly performed. Hypocitraturia was found in 69% of patients, with KTx patients having a significantly lower urinary citrate excretion than those receiving calcineurin inhibitors for other reasons. Secondly, we found hyperoxaluria in 35% of patients, again especially in those after KTx. No significant difference in urinary substances was seen comparing CsA with tacrolimus treatment. Urolithiasis was found in one and calcium-oxalate crystal deposition in biopsy specimen of three KTx patients. Calcineurin inhibitor treatment can lead to significant hypocitraturia, especially in patients after KTx receiving the highest dose of medication. Hyperoxaluria is primarily the result of a removal of significant body oxalate stores, deposited during dialysis, but may not be suspected as a specific side effect of calcineurin inhibitor therapy. Both findings can increase the risk for urolithiasis or nephrocalcinosis.
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PMID:Hypocitraturia as a risk factor for nephrocalcinosis after kidney transplantation. 1578

This study was conducted to evaluate the etiological and clinical characteristics of urolithiasis in Iraqi children. From 1999 to 2004, 204 children with renal calculi were evaluated. The age range of the patients was 4 months to 14 years, 61.3% of the patients were under 5 years. Male to female ratio was 2.8:1. The mean age at onset of symptoms was 3.2 years, and stone disease was diagnosed at a mean of 3.5 years. Hematuria (44.6%) and pain (28.4%) were the main clinical presentation. Of the 204 patients 45.1% had a family history of stones. Consanguinity was recorded in 72%; 75.5% had metabolic disorders. Stones were located at multiple sites in 80 patients, or 39.2%; 58 of these 80, or 72.5%, had metabolic disorders. Multiple stones were present in 47 (23%); 72.3% were related to metabolic disorders. In 126 patients, or 61.8%, both kidneys were involved equally. Bladder stones were found in 11.3%. Staghorn calculi occurred in 29 patients, or 14.2%; 27 of these had recurrent urinary tract infection (UTI). Nephrocalcinosis was diagnosed in 7, or 3.4%; all had metabolic disorders. Etiology of stone formation was established in 189 patients, or 92.6%, whereas 15, or 7.4%, had idiopathic stones. Metabolic disorders were the commonest cause in 106 patients (52%); 52 patients were classified as infective (25.5%). Anatomical defects were present in 25 (12.2%) and 6 children (2.9%) with primary endemic bladder calculi. Coexisting UTI was common (36.8%) in the metabolic group. We concluded that urolithiasis is a serious problem among Iraqi children, with early onset of presentation. Metabolic disorders were the major causes, but can be masked by associated UTI. Proper management of UTI with a careful metabolic assessment of young stone formers is valuable in combating urolithiasis.
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PMID:Etiological and clinical patterns of childhood urolithiasis in Iraq. 1601 May 96

Regular calculation of urinary crystallization risk indices in patients suffering from urolithiasis is a recommended measure for treatment adjustment. The more the patient experiences either extensive stone formation or an enhanced recurrence rate, the more important risk index calculations. In patients suffering from primary hyperoxaluria type 1 (PH1), both criteria are met. Different methods of risk determination are known. All strategies for measuring the calcium oxalate (CaOx) crystallization risk of a given urine principally determine this parameter from voided urine. This "bladder urine", however, has possibly passed stone material located in the urinary tract and thus may be depleted in lithogenic components. This is commonly the case for patients with PH1, who mostly experience a massive stone burden or severe nephrocalcinosis. Hence, the question arises as to whether we can adequately determine the crystallization risk in the urine of stone-bearing PH1-patients or not. Based on model calculations, we show that the determination of CaOx formation risk in PH1-patients requires knowledge of the restrictions in risk index interpretation: risk indices calculated from urinalysis (e.g. EQUIL) still indicate, even after strong in vivo stone formation, an enhanced but in fact strongly underestimated risk value. However, the outcome "enhanced" masks the patient's true risk situation. The BONN Risk Index (BRI), in contrast, discloses the process of extreme in vivo crystal formation. As determined, inter alia, from the urinary concentration of free ionized calcium ([Ca(2+)]), BRI approaches abnormally low values, as, in consequence of CaOx - formation, [Ca(2+)] tends to values close to zero. Thus, calculations of urinalysis-based risk indices alone are insufficient strategies for the quantification of a PH1 patient's CaOx crystallization risk.
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PMID:Problems in the investigation of urine from patients suffering from primary hyperoxaluria type 1. 1615 74

Dent's disease (DD) involves nephrocalcinosis, urolithiasis, hypercalciuria, LMW proteinuria, and renal failure in various combinations. Males are affected. It is caused by mutations in the chloride channel CLCN5 gene. It has been suggested that DD is underdiagnosed, occurring in less overt forms, apparently without family history. A possible approach to this problem is to search for CLCN5 mutations in patients who may have a high prevalence of mutations: end-stage renal disease (ESRD) patients with previous calcium, struvite, or radio-opaque (CSR) stones. We looked for CLCN5 mutations in 25 males with ESRD-CSR stones selected from all of the patients (1,901 individuals, of which 1,179 were males) of 15 dialysis units in the Veneto region. One DD patient had a new DD mutation (1070 G > T) in exon 7. The new polymorphism IVS11-67 C > T was detected in intron 11 in one patient and one control. We also found 28 females with ESRD and stone history, and seven more males with ESRD and non-CSR stones. The prevalence of stone formers among dialysis patients in our region was 3.2%, much lower than the prevalence observed in older studies. Struvite stones continue to play a major role in causing stone-associated ESRD .
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PMID:Dent's disease and prevalence of renal stones in dialysis patients in Northeastern Italy. 1624 50

The kidney function can be assessed by a number of methods. The urinary excretion of enzymes, in particular N-acetyl-beta-D-glucosaminidase (NAG), is considered a relatively simple, cheap, fast and non-invasive method in the detection and follow-up of renal tubular function under various conditions. The determination of urinary NAG provides a very sensitive and reliable indicator of renal damage, such as injury or dysfunction due to diabetes mellitus, nephrotic syndrome, inflammation, vesicoureteral reflux, urinary tract infection, hypercalciuria, urolithiasis, nephrocalcinosis, perinatal asphyxia, hypoxia, hypertension, heavy metals poisoning, treatment with aminoglycosides, valproate, or other nephrotoxic drugs. This paper gives an overview of the current use of urinary NAG in the detection of renal injury.
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PMID:The diagnostic role of urinary N-acetyl-beta-D-glucosaminidase (NAG) activity in the detection of renal tubular impairment. 1625 16

In primary hyperoxaluria the deficiency or mistargeting of hepatic alanine-glyoxylate aminotransferase (AGT) leads to the overproduction of oxalate resulting in hyperoxaluria and renal damage due to urolithiasis and/or nephrocalcinosis. Presently, the cure of the metabolic defect can be achieved only by liver transplantation. While for patients with end-stage renal disease combined hepatorenal transplantation is recommended, the concept of preemptive liver transplantation (PLTX), i.e. cure of the metabolic defect before renal damage occurs, has received considerable attention. Due to the heterogenous clinical course in PH1, optimal timing of PLTX is a matter of debate. Advocators of PLTX would consider a patient with a slowly declining GFR, reaching levels of 40-60 ml/min/1.73 m(2), as an ideal candidate, while others would continue medical treatment in these patients and opt for rapid combined liver-kidney transplantation if GFR reaches even lower levels. This review will discuss the background and rationale of PLTX and gives an update on 11 patients with PLTX who have been reported in the literature to date.
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PMID:The role of preemptive liver transplantation in primary hyperoxaluria type 1. 1628 78


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