Urinary tract infection in children associated with idiopathic hypercalciuria

Pharmacological interventions for preventing complications in patients with idiopathic hypercalciuria: A systematic review

OBJECTIVE

To assess the effects of pharmacological interventions in patients with idiopathic hypercalciuria.

METHODS

We performed a search of multiple databases, trial registries, grey literature and conference proceedings up to October 2019. We included randomized and quasi-randomized controlled trials that examined any pharmacological intervention for preventing complications of idiopathic hypercalciuria (given for at least four months and six of follow-up). The primary outcomes were stone-free patients, urinary symptoms and severe adverse events.

RESULTS

We included five RCTs (n=446 patients, all adults, 4 in individuals with kidney stones and 1 in postmenopausal women with osteoporosis). Diuretics were likely to increase the number of stone-free patients (RR 1.61, 95% CI 1.33-1.96, moderate quality of evidence (QoE)); 274 more stone-free patients/1000 patients treated (95% CI: 148-432) and produced a slight decrease in the stone formation rate (mean difference -0.18, 95% CI -0.30 to -0.06, low QoE); 180 fewer stones/year/1000 patients treated (95% CI: 300 r to 60). No data on urinary symptoms were reported. The association between diuretic use and severe adverse events was uncertain (RR 5.00, 95% CI 0.60-41.88, very low QoE); 4 more severe adverse events/1000 patients treated (95% CI: 0 fewer to 39 more).

CONCLUSIONS

The addition of diuretics to a normal or modified diet probably reduces the number of stone recurrences and may decrease the stone formation rate. It is uncertain whether diuretics increase the occurrence of severe adverse events. There were no studies investigating other outcomes or in children.

Molecular mechanisms altering tubular calcium reabsorption

The majority of calcium filtered by the glomerulus is reabsorbed along the nephron. Most is reabsorbed from the proximal tubule (> 60%) via a paracellular pathway composed of the tight junction proteins claudins-2 and -12, a process driven by sodium and consequently water reabsorption. The thick ascending limb reabsorbs the next greatest amount of calcium (20-25%), also by a paracellular pathway composed of claudins-16 and -19. This pathway is regulated by the CaSR, whose activity increases the expression of claudin-14, a protein that blocks paracellular calcium reabsorption. The fine tuning of urinary calcium excretion occurs in the distal convoluted and connecting tubule by a transcellular pathway composed of the apical calcium channel TRPV5, the calcium shuttling protein calbindin-D_28K and the basolateral proteins PMCA1b and the sodium calcium exchanger, NCX. Not surprisingly, mutations in a subset of these genes cause monogenic disorders with hypercalciuria as a part of the phenotype. More commonly, "idiopathic" hypercalciuria is encountered clinically with genetic variations in CLDN14, the CASR and TRPV5 associating with kidney stones and increased urinary calcium excretion. An understanding of the molecular pathways conferring kidney tubular calcium reabsorption is employed in this review to help explain how dietary and medical interventions for this disorder lower urinary calcium excretion.

Pharmacological interventions for preventing complications in patients with idiopathic hypercalciuria: A systematic review

OBJECTIVE

To assess the effects of pharmacological interventions in patients with idiopathic hypercalciuria.

METHODS

We performed a search of multiple databases, trial registries, grey literature and conference proceedings up to October 2019. We included randomized and quasi-randomized controlled trials that examined any pharmacological intervention for preventing complications of idiopathic hypercalciuria (given for at least four months and six of follow-up). The primary outcomes were stone-free patients, urinary symptoms and severe adverse events.

RESULTS

We included five RCTs (n=446 patients, all adults, 4 in individuals with kidney stones and 1 in postmenopausal women with osteoporosis). Diuretics were likely to increase the number of stone-free patients (RR 1.61, 95% CI 1.33-1.96, moderate quality of evidence (QoE)); 274 more stone-free patients/1000 patients treated (95% CI: 148-432) and produced a slight decrease in the stone formation rate (mean difference -0.18, 95% CI -0.30 to -0.06, low QoE); 180 fewer stones/year/1000 patients treated (95% CI: 300 r to 60). No data on urinary symptoms were reported. The association between diuretic use and severe adverse events was uncertain (RR 5.00, 95% CI 0.60-41.88, very low QoE); 4 more severe adverse events/1000 patients treated (95% CI: 0 fewer to 39 more).

CONCLUSIONS

The addition of diuretics to a normal or modified diet probably reduces the number of stone recurrences and may decrease the stone formation rate. It is uncertain whether diuretics increase the occurrence of severe adverse events. There were no studies investigating other outcomes or in children.

Renal Allograft With Calcium Oxalate Deposition: Association with Urinary Tract Infection and Development of Interstitial Fibrosis

OBJECTIVES

The interaction between calcium oxalate deposition and urinary tract infection is not well established. We aimed to identify the association between these and to determine the role of calcium oxalate deposition on interstitial fibrosis development.

MATERIALS AND METHODS

Renal allograft biopsies of 967 patients were reviewed to identify those with calcium oxalate deposition in the renal allograft, with 27 (2.8%) identified. Follow-up biopsies were conducted to reevaluate for calcium oxalate presence and interstitial fibrosis development. At time of biopsy, presence of urinary tract infection and oxaluria was also examined from medical records.

RESULTS

Mean time for development of calcium oxalate deposition in renal allografts was 1.7 ± 0.4 and 32.7 ± 21.6 months in patients with primary and secondary oxalosis, respectively (P < .001). Of 27 patients with calcium oxalate deposition, 7 (25.9%) showed tubulointerstitial nephritis, with 2 also having urinary tract infection. Four patients (14.8%) had only urinary tract infection. Causes of tubulointerstitial nephritis were secondary to bacterial infection in 2 and secondary to viral infection in 5 patients (2 polyomaviruses, 2 cytomegaloviruses, 1 adenovirus). Time until development of interstitial fibrosis after calcium oxalate deposition was 3.5 ± 2.1 and 10.3 ± 4.1 months in patients with primary and secondary oxalosis, respectively (P = .01). Time until graft loss after calcium oxalate deposition was 9.3 ± 7.8 and 21.8 ± 12 months in those with primary and secondary oxalosis (P < .001), with 1-, 3-, and 5-year kidney graft survival of 43%, 28%, and 0% and 100%, 100%, and 67% in those with primary and secondary oxalosis, respectively.

CONCLUSIONS

Calcium oxalate deposits increased the risk of urinary tract infection and tubulointerstitial nephritis, with bacteria inducing increased presence of calcium oxalate deposition in a renal allograft. Calcium oxalate deposition had a significant influence on interstitial fibrosis development, therefore negatively affecting graft survival.

The comparison of ultrasound and non-contrast helical computerized tomography for children nephrolithiasis detection

AIMS

Nephrolithiasis is less common in children than adults, but its diagnosis and management in children may be more perplexing. In this article, we compare two imaging ultrasound (US) and non-contrast helical computerized tomography (CT) for diagnosis of nephrolithiasis.

SUBJECTS AND METHODS

A total of 20 children who diagnosed as nephrolithiasis by US were imaged simultaneously by non-contrast helical CT. Their history like as family history in first and second degree relatives and urine analysis for hematuria and urine randomly calcium to creatinine ratio was obtained. All data analyzed by χ(2) and Mann-Whitney U-test in SPSS 16 and P < 0.05 was considered to be significant.

RESULTS

Out of 20 cases, only 5 cases diagnosed as nephrlithiasis by US were confirmed by CT method 2 out of 20 cases had another extrarenal origin for their complaint who diagnosed wrongly as nephrolithiasis by US. Stone size based of US that was confirmed by CT method was larger 4.6 ± 1.5 (minimum 3 max 6 mm) than non-confirmed ones 2.3 ± 0.7 mm (P 0.002). Hematuria occurred more in correct diagnosed compared with misdiagnosed (P 0.005). Positive family history and urine calcium ratio was not differed between two groups.

CONCLUSIONS

Non contrast helical CT is essential to confirm of nephrolithiasis and other extrarenal origin of complaints, which diagnosed wrongly as nephrolithiasis in children. Stone size and presence of hematuria are two major factors for right diagnosis of nephrolithiasis as US method but Urine calcium excretion ratio or positive family history cannot be predictive as this study.

Dietary interventions for preventing complications in idiopathic hypercalciuria

BACKGROUND

Idiopathic hypercalciuria is an inherited metabolic abnormality that is characterised by excessive amounts of calcium excreted in the urine by people whose calcium serum levels are normal. Morbidity associated with idiopathic hypercalciuria is chiefly related to kidney stone disease and bone demineralisation leading to osteopenia and osteoporosis. Idiopathic hypercalciuria contributes to kidney stone disease at all life stages; people with the condition are prone to developing oxalate and calcium phosphate kidney stones. In some cases, crystallised calcium can be deposited in the renal interstitium, causing increased calcium levels in the kidneys. In children, idiopathic hypercalciuria can cause a range of comorbidities including recurrent macroscopic or microscopic haematuria, frequency dysuria syndrome, urinary tract infections and abdominal and lumbar pain. Various dietary interventions have been described that aim to decrease urinary calcium levels or urinary crystallisation.

OBJECTIVES

Our objectives were to assess the efficacy, effectiveness and safety of dietary interventions for preventing complications in idiopathic hypercalciuria (urolithiasis and osteopenia) in adults and children, and to assess the benefits of dietary interventions in decreasing urological symptomatology in children with idiopathic hypercalciuria.

SEARCH METHODS

We searched the Cochrane Renal Group's Specialised Register (23 April 2013) through contact with the Trials' Search Co-ordinator using search terms relevant to this review. Studies contained in the Specialised Register are identified through search strategies specifically designed for CENTRAL, MEDLINE and EMBASE.

SELECTION CRITERIA

We included all randomised controlled trials (RCTs) and quasi-RCTs that investigated dietary interventions aimed at preventing complications of idiopathic hypercalciuria, compared with placebo, no intervention, or other dietary interventions regardless of route of administration, dose or amount.

DATA COLLECTION AND ANALYSIS

Studies were assessed for inclusion and data extracted using a standardised data extraction form. We calculated risk ratios (RR) for dichotomous outcomes and mean differences (MD) for continuous outcomes, both with 95% confidence intervals (CI).

MAIN RESULTS

We included five studies (379 adult participants) that investigated a range of interventions. Lack of similarity among interventions investigated meant that data could not be pooled. Overall, study methodology was not adequately reported in any of the included studies. There was a high risk of bias associated with blinding (although it seems unlikely that outcomes measures were unduly influenced by lack of intervention blinding), random sequence generation and allocation methodologies were unclear in most studies, but selective reporting bias was assessed as low.One study (120 participants) compared a low calcium diet with a normal calcium, low protein, low salt diet for five years. There was a significant decrease in numbers of new stone recurrences in those treated with the normal calcium, low protein, low salt diet (RR 0.77, 95% CI 0.61 to 0.98). This diet also led to a significant decrease in oxaluria (MD 78.00 µmol/d, 95% CI 26.48 to 129.52) and the calcium oxalate relative supersaturation index (MD 1.20 95% CI 0.21 to 2.19).One study (210 participants) compared a low salt, normal calcium diet with a broad diet for three months. The low salt, normal calcium diet decreased urinary calcium (MD -45.00 mg/d, 95% CI -74.83 to -15.17) and oxalate excretion (MD -4.00 mg/d, 95% CI -6.44 to -1.56).A small study (17 participants) compared the effect of dietary fibre as part of a low calcium, low oxalate diet over three weeks, and found that although calciuria levels decreased, oxaluria increased. Phyllanthus niruri plant substrate intake was investigated in a small subgroup with hypercalciuria (20 participants); there was no significant effect on calciuria levels occurred after three months of treatment.A small cross-over study (12 participants) evaluating the changes in urinary supersaturation indices among patients who consumed calcium-fortified orange juice or milk for one month found no benefits for participants.None of the studies reported any significant adverse effects associated with the interventions.

AUTHORS' CONCLUSIONS

Long-term adherence (five years) to diets that feature normal levels of calcium, low protein and low salt may reduce numbers of stone recurrences, decrease oxaluria and calcium oxalate relative supersaturation indexes in people with idiopathic hypercalciuria who experience recurrent kidney stones. Adherence to a low salt, normal calcium level diet for some months can reduce calciuria and oxaluria. However, the other dietary interventions examined did not demonstrate evidence of significant beneficial effects.No studies were found investigating the effect of dietary recommendations on other clinical complications or asymptomatic idiopathic hypercalciuria.

Does hydrochlorothiazide prevent recurrent urinary tract infection in children with idiopathic hypercalciuria?

OBJECTIVE

Idiopathic hypercalciuria (IHC) has been recognized as a common disorder in childhood, and is a major factor in the formation of renal stones and urinary tract infections (UTIs). Since hydrochlorothiazide ameliorates hypercalciuria, we assessed its efficacy in preventing recurrent UTIs in hypercalciuric girls.

MATERIALS AND METHODS

This research was a single blind randomized clinical trial. One hundred 1‒12-year-old girls, who were followed in pediatric nephrology outpatient clinics of two referral hospitals in Markazi Province of Iran, were recruited. All patients had IHC and at least two UTIs in 1 year, without any underlying anatomic or functional abnormality of urinary tract. Patients were randomly divided into two equal groups. One group received instructions regarding general preventive measures for UTI and the other group, in addition to these measures, received 1 mg/kg/day hydrochlorothiazide as morning dose. Then recurrence of UTI in the two groups was evaluated.

RESULTS

The mean age was 7.28 ± 1.9 years. In both groups, the incidence of UTI recurrence was 66%.

CONCLUSION

On the basis of these results, we reject the hypothesis that treating hypercalciuria is beneficial in preventing repeated UTIs. The association between UTIs and IHC needs to be more closely studied and attention to eliminating confounding factors is necessary.

The association between urinary tract infection and idiopathic hypercalciuria in children

BACKGROUND

Identifying the risk factors is important in prevention of urinary tract infections (UTIs) in children. The aim of this study is to evaluate the association of UTI and idiopathic hypercalciuria (IHC).

METHODS

Two hundred and twenty-four children aged between 1 month and 16 years and diagnosed to have UTI were evaluated for urinary calcium excretion. The children were diagnosed to have IHC if their urinary calcium/creatinine ratios in at least two different spot urine samples were >0.6 between 0-1 year old and ≥0.21 over 1 year or daily calcium excretion >4 mg/kg.

RESULTS

The frequency of IHC was found to be 16.7%. Family history of urolithiasis, parental consanguinity, presentation with abdominal pain, loss of appetite, and discomfort were found to be significantly higher in the IHC group. No association was found between IHC and the recurrence of UTI, presence of vesicoureteral reflux, renal scar formation, and the prognosis.

CONCLUSIONS

IHC should be considered among the risk factors for UTI and should be investigated particularly in patients with family history of urinary stones and suggestive complaints of IHC.

Bone disease in pediatric idiopathic hypercalciuria

Idiopathic hypercalciuria (IH) is the leading metabolic risk factor for urolithiasis and affects all age groups without gender or race predominance. IH has a high morbidity with or without lithiasis and reduced bone mineral density (BMD), as described previously in pediatric patients as well as in adults. The pathogenesis of IH is complex and not completely understood, given that urinary excretion of calcium is the end result of an interplay between three organs (gut, bone and kidney), which is further orchestrated by hormones, such as 1,25 dihydroxyvitamin D, parathyroid hormone, calcitonin and fosfatonins (i.e., fibroblast growth-factor-23). Usually, a primary defect in one organ induces compensatory mechanisms in the remaining two organs, such as increased absorption of calcium in the gut secondary to a primary renal loss. Thus, IH is a systemic abnormality of calcium homeostasis with changes in cellular transport of this ion in intestines, kidneys and bones. Reduced BMD has been demonstrated in pediatric patients diagnosed with IH. However, the precise mechanisms of bone loss or failure of adequate bone mass gain are still unknown. The largest accumulation of bone mass occurs during childhood and adolescence, peaking at the end of the second decade of life. This accumulation should occur without interference to achieve the peak of optimal bone mass. Any interference may be a risk factor for the reduction of bone mass with increased risk of fractures in adulthood. This review will address the pathogenesis of IH and its consequence in bone mass.

Urinary calcium and uric acid excretion in children with vesicoureteral reflux

Urolithiasis is relatively common in children, and identifiable predisposing factors for stone formation, including metabolic and structural derangements, can be established in most cases. Vesicoureteral reflux (VUR) is a common cause of kidney stone formation. The pathophysiological mechanism of urolithiasis in reflux is related to urinary tract infection and urinary stasis, both of which promote urinary crystal formation, but metabolic causes, such as crystallurias (mostly hypercalciuria), may also be involved in this process. However, few studies on urinary calcium and uric acid excretion in children with VUR have been conducted. We have studied the frequency of hypercalciuria and hyperuricosuria in children with VUR and compared the results with those from a control group. The VUR group comprised 108 children with VUR (19 boys, 89 girls; age range 3 months to 12 years), and the control group comprised 110 healthy children without any history of reflux or urinary tract infection (30 boys, 80 girls; age range 2 months to 12 years). Fasting urine was analyzed for the calcium/creatinine (Ca/Cr) and uric acid/creatinine (UA/Cr) ratios. Hypercalciuria was more frequently diagnosed in the VUR patients than in the control group (21.3 vs. 3.6%; P = 0.0001). Significant differences between the two groups were also found for the mean Ca/Cr and UA/Cr ratios (P = 0.0001 and P = 0.0001, respectively). No differences were found in the urinary Ca/Cr or UA/Cr ratios related to VUR grading or unilateral/bilateral VUR in the patient group, with the exception of those for hypercalciuria and mild VUR (P = 0.03). The association of urinary stones and microlithiasis in the VUR group was 29.6%. Our results demonstrate that the frequency of hypercalciuria and hyperuricosuria was higher in pediatric patients with VUR than in healthy children. Knowing this relationship, preventive and therapeutic interventions for stone formation in VUR could be greatly expanded.

Recurrent urinary tract infections in an infant with antenatal Bartter syndrome

BACKGROUND

antenatal variant of Bartter syndrome is characterized by a history of polyhydramnios, premature birth, metabolic alkalosis, hypokalemia, polyuria and renal salt wasting. In this report we present a premature female baby with antenatal Barter syndrome who had three episodes of urinary tract infection (UTI), without evidence for congenital anomaly of the kidneys or urinary tract.

METHODS

antenatal Bartter syndrome was diagnosed according to the standard criteria. Ultrasound scan and voiding cystourethrography were performed to exclude congenital anomaly of the kidneys and urinary tract.

RESULTS

the baby presented with early hyperkalemia and acidosis. The typical biochemical features of the Bartter syndrome were observed in the second month. Despite appropriate treatment she had persistent hypercalciuria. The clinical course was complicated with recurrent episodes of febrile UTIs. Urinary tract system imaging did not demonstrate congenital anomalies. She finally died of severe dehydration, acidosis and renal failure.

CONCLUSION

since no congenital anomaly of the kidneys or urinary tract was demonstrated in our patient, we believe that severe, persistent hypercalciuria is the most important risk factor for development of recurrent UTIs.

Diagnosis and management of hypercalciuria in children

PURPOSE OF REVIEW

In this review, recent advances in the epidemiology, genetics, clinical associations and management of idiopathic hypercalciuria will be discussed.

RECENT FINDINGS

A significant genetic contribution exists in the pathophysiology of hypercalciuria. Although several candidate genes and genetic alterations have been proposed, identification of precise gene(s) responsible remains elusive. Decreased bone density has been increasingly associated with hypercalciuria. Recent publications have suggested that bisphosphonates may play a role in the management in patients in whom both hypercalciuria and decreased bone density are present.

SUMMARY

Idiopathic hypercalciuria is a common disorder in children and can present with a range of clinical presentations such as hematuria, voiding dysfunction, flank pain, abdominal pain, nephrolithiasis, urinary tract infection and decreased bone mineral density. Dietary modifications are often sufficient in the management of hypercalciuria. If the symptoms persist or a rare monogenic disorder is present, consideration should be given to medical treatment with a thiazide diuretic and/or citrate therapy.

Pharmacological interventions for preventing complications in idiopathic hypercalciuria

BACKGROUND

Idiopathic hypercalciuria is an inherited metabolic abnormality characterised by excessive amounts of calcium excreted into the urine in patients with normal serum levels of calcium. The morbidity of hypercalciuria is related to kidney stone disease and bone demineralization. In children, hypercalciuria can cause recurrent haematuria, frequency-dysuria syndrome, urinary tract infection and abdominal and lumbar pain. Several pharmacological treatments have been described that can decrease the levels of urinary calcium or its index of urinary crystallization.

OBJECTIVES

To assess the benefits and harms of pharmacological interventions for preventing complications and decreasing urological symptoms in patients with idiopathic hypercalciuria.

SEARCH STRATEGY

We searched MEDLINE, EMBASE, the Cochrane Renal Group's specialised register, the Cochrane Central Register of Controlled Trials (CENTRAL, The Cochrane Library), handsearched relevant conference proceedings and reference lists of articles.

SELECTION CRITERIA

All randomised controlled trials (RCTs) and quasi-RCTS that compared any pharmacological intervention for preventing complications in idiopathic hypercalciuria, with placebo, other pharmacological intervention or a different administration mode or dose of the same treatment given for a minimum duration of four months and had a follow-up period of at least six months.

DATA COLLECTION AND ANALYSIS

Four authors assessed the studies for inclusion and extracted the data. Disagreements were resolved through discussion. Results were expressed as risk ratios (RR) with 95% confidence intervals (CI) or mean difference (MD).

MAIN RESULTS

Five studies (316 adult patients) were included. Four compared thiazides with standard treatment (periodic clinical follow-up and increased water intake) or specific dietary recommendations and one analysed the effect of thiazide plus a neutral potassium salt. There was a significant decrease in the number of new stone recurrences in those treated with thiazides (RR 1.61, 95% CI 1.33 to 1.96), although the follow-up periods varied. The stone formation rate also showed a statistically significant decrease in the patients treated with diuretics (MD -0.18, 95% CI -0.30 to -0.06). Thiazides plus potassium salts significantly decreased calciuria and vitamin D levels.

AUTHORS' CONCLUSIONS

There is some evidence that in patients with idiopathic hypercalciuria and recurrent stones, the addition of thiazides to a normal or modified diet for short to long periods (five months to three years) reduced the number of stone recurrences and decreased the stone formation rate. Thiazides and neutral potassium phosphate decreased calciuria in symptomatic patients with idiopathic hypercalciuria. There were no studies investigating the effect of pharmacological treatment on other clinical complications or asymptomatic idiopathic hypercalciuria.

Low bone density in children with hypercalciuria and/or nephrolithiasis

The objective of this study was to identify how many children with hypercalciuria and/or nephrolithiasis have a low bone density and whether the risk of low bone density can be identified by 24-h urine stone-risk profiles and/or growth parameters. A retrospective chart review was performed on 110 idiopathic hypercalciuria and/or kidney stone patients who received both a 24-h urine for stone-risk profile and a dual-energy X-ray densitometry scan. Patients were divided into low bone density vs. normal bone density groups and hypercalcuria verus nephrolithiasis groups and analyzed for differences in growth parameters, urine stone-risk profiles, and bone densities. Overall, 47% had a bone density z score < -1, and 26% had a bone density z score < -2. Patients with a low bone density had a higher body mass index and lower urine creatinine and ammonium than those with a normal bone density. Patients with nephrolithiasis had a lower bone density z score than patients with hypercalcuria and no nephrolithiasis. Clinicians should be aware of the increased incidence of low bone density in children with hypercalciuria and nephrolithiasis. The effect of hypercalciuria and nephrolithiasis treatment on bone density and the natural progression of the bone density in the studied patient population warrants further investigation.

Idiopathic hypercalciuria associated with urinary tract infection in children

The aim of this study was to evaluate the association between idiopathic hypercalciuria (IH) and urinary tract infection (UTI) in children. This prospective clinical study included 75 patients with UTI (without urinary tract malformations and lithiasis) and a control group of 30 healthy children. Of the total number of patients with UTI, 21% (n = 16/75) had IH, but only 7% (n = 2/30) with IH were reported in the control group (p < 0.05). Recurrent UTI affected 33% (n = 25/75) of patients , and in 67% (n = 50/75) of patients, UTI was diagnosed for the first time. In the group of patients with recurrent UTI, 44% (n = 11/25) had IH, but only 10% (n = 5/50) were reported in the group of patients with first-time UTI (p < 0.05). The results of multifactorial logistic regression analysis showed that clinical and laboratory parameters (recurrent UTI, dysuria, and microscopic hematuria) may predict the diagnosis of IH in 80% of patients and absence of IH in 87% of cases. In our opinion, IH is a major contributing factor to UTI, especially to recurrent UTI in children.

Evaluation of histologic changes in the urinary tract of hypercalciuric rats

Idiopathic hypercalciuria (IH) has been speculated to have a predisposing role in the development of urinary tract infection (UTI), due to the uroepithelial cell damage it leads to. In this study, we aimed to investigate the effects of hypercalciuria on the bladder, ureters, and kidneys in rats with experimentally induced hypercalciuria.Normocalcemic hypercalciuria was induced by furosemide (60 mg/100 mL of drinking water) administration to 16-week-old male Wistar Albino rats for 14 days. Calciuria (calcium/creatinine ratio, mg/mg, Ca/Cr) increased from 0.07+/-0.01 at the beginning of administration to 0.41+/-0.1 on day 14 (p=0.000). The Ca/Cr ratio was 0.14+/-0.06 at the beginning of the study and 0.25+/-0.06 on day 14 in the control group rats (p=0.002 vs. the hypercalciuric group rats on day 14). Bladder, ureter, and kidney specimens of the rats, dissected on the 14th day, were fixed in 10% formalin and 2.5% gluteraldehyde solutions for light and electron microscopic examination, respectively. Histopathological and ultrastructural examination of the hypercalciuric rats revealed proliferation and apical cytoplasmic vacuole formation in transitional epithelial cells, mitotic activity in the intermediate cell line, vasodilatation, edema, and separation of collagen fibers in the bladder and ureter specimens. Light microscopic examination of the kidney specimens revealed a lot of erythrocyte in the glomerular capillary lumen, while electron microscopy revealed vacuolization of proximal and distal tubules, tubular degeneration, interstitial edema, and vasodilatation.In this study, hypercalciuria was observed to have adverse effects on the cell architecture of the uroepithelium and disruption of the epithelial barrier of the bladder and ureters and all kidney structures, especially on the proximal epithelial cells.

Medical evaluation and treatment of urolithiasis

Nephrolithiasis is responsible for 1 in 1000 to 1 in 7600 pediatric hospital admissions annually throughout the United States. Seventy-five percent of children with nephrolithiasis have an identifiable predisposition to stone formation. This article reviews the different causes and disease states associated with nephrolithiasis in the pediatric population. The initial evaluation and the metabolic evaluation of children with nephrolithiasis are reviewed. Treatment modalities for the different stone types are also described.

[Prevention and alternative methods for prophylaxis of recurrent urinary tract infections in women]

General recommendations to prevent recurrent urinary tract infections (rUTI) result in about one-third of patients remaining free of recurrences. Oral and parenteral immunotherapy were effective in several controlled studies for prevention of rUTI. These therapies can be combined with acute antibiotic therapy. Vaginal prophylaxis with oestriol has proven its positive effect without serious gynaecological side effects. Also there is increasing evidence that cranberries prevent rUTI. The exact mode (juice, tablets or preserved berries), dosage and duration of this therapy remain to be defined. There are also promising therapy modalities such as changing bacterial gut flora, general immune response (acupuncture, inpatient rehabilitation) and urine acidity.

Hypercalciuria and recurrent urinary tract infections: incidence and symptoms in children over 5 years of age

Hypercalciuria is an important and common risk factor in the formation of renal stones. In this study we evaluated the incidence and the clinical presentation of hypercalciuria in 75 children over 5 years of age with the diagnosis of recurrent urinary tract infection (UTI). We measured random urinary calcium/creatinine value (three times), 24-h urinary calcium excretion, serum calcium, phosphorus, electrolytes, blood gas, blood urea nitrogen and creatinine levels. Hypercalciuria was found in 32 patients (43%). The mean urinary calcium/creatinine ratio for hypercalciuric patients was 0.50+/-0.21 mg/mg (min: 0.24, max: 2.60). The mean urinary calcium/creatinine ratio for the rest of the study population--those without hypercalciuria--was 0.10+/-0.04 mg/mg (min: 0.01, max: 0.18). Presenting symptoms of the hypercalciuric patients and normocalciuric patients were similar. History of familial urolithiasis was positive in 19 patients (59%). Predisposing urinary tract abnormalities in recurrent UTI was shown in 12 of the hypercalciuric patients (12/32, 37.5%) and 8 of the normocalciuric patients (8/43, 19%) without a statistically significant difference between. We conclude that hypercalciuria is not a rare finding among recurrent UTI cases in Turkish children. Hypercalciuria does not modify the clinical presentation of UTI, and we suggest the investigation of urinary calcium excretion in children with recurrent UTI.

Infection and urinary stones

PURPOSE OF REVIEW

Despite modern antibiotic therapy and technological advances in lithotripsy, the presence of infection in urinary stone patients as well as infectious stones are still a significant cause of morbidity and mortality. Many new investigations are focusing on the pathogenesis and treatment of these difficult cases.

RECENT FINDINGS

Most of the current literature on the subject focuses on pathogenesis of infectious urinary stones. The remaining literature highlights difficult cases, outcomes of treatments, and overall reviews of the subject.

SUMMARY

Recent findings lend more theories as to how infection leads to stone formation. Further investigation is critically needed to improve the outcomes of patients suffering from infections with urinary stones and infectious stones.