Role of urinary N-acetyl-beta-glucosaminidase in diagnosis of kidney diseases

N-acetyl-beta-D-glucosaminidase [NAG] is a lysosomal enzyme present in the proximal convoluted tubules of the kidneys that may be used as a marker of proximal tubular damage and nephrotoxicity. An abnormal urinary NAG excretion has been reported in different kinds of renal disorders such as acute kidney injury, urinary tract infection, vesicoureteral reflux; diabetes mellitus; nephrotic syndrome; glomerulonephritis; hypertension; perinatal asphyxia; heavy metals poisoning; drug nephrotoxicity, renal allograft rejection; and heart failure. This paper provides an overview of the diagnostic value of urinary NAG in the nephrourology field

sensitivity of ultrasonography in detecting renal cortical defects in pyelonephritic patients with or without vesicoureteral reflux

The presence of renal scarring has been documented in 5% to 15% of febrile urinary tract infections. The main aim of this study was to compare the value of renal ultrasonography and cortical scintigraphy with technetium-99m dimercaptosuccinic acid [DMSA] in detecting renal cortical defects in acute pyelonephritis. Between June 2003 and February 2012 a prospective cohort study of patients aged 1 month to 14 years of age was conducted. Pediatric patients with documented urinary tract infections were evaluated with renal ultrasonography, voiding cystoureterography [VCUG] and DMSA scintigraphy. Statistical test was two-tailed and was considered significant when P< 0.05. The results of DMSA scans showed 70.2% of cases as being abnormal. Renal ultrasonographies were reported to be normal in 72.45 and showed mild hydronephrosis in 37.7% of cases, moderate to severe hydronephrosis in 40.62%, stone formation in 13.66% and scar formation or decreased cortical thickness in 8.2%. There was a significant difference in ultrasonography reports between patients with normal and abnormal DMSA scans [P< 0.012] but there was no significant difference in detection of scar formation between DMSA scan results and those of ultrasonography in our patients. Among patients with severe abnormalities on DMSA scintigraphy the percent of cases with vesicoureteral reflux was significantly higher than those with normal scans or mild to moderate changes on DMSA scintigraphy. [46.3% vs 26.9%]. We concluded that ultrasonography is a sensitive method for detection of renal cortical defects and ultrasonography can also predict the presence of vesicoureteral reflux in pyelonephritic patients

Prognostic factors and mortality rate in neonates with acute renal injury in NICU

Acute Renal Injury [AKI] is a frequent clinical condition in the Neonatal Intensive Care Units [NICUs]. Most AKI causes are preventable; performing rapid preventive, diagnostic, and therapeutic measures could prevent the potential complications. The present study was conducted to define the risk factors and mortality rates of neonates with and without AKI admitted in the NICU of a tertiary care hospital. Demographic and biochemical data of NICU of Mahdieh Hospital were collected and analyzed. More than twofold increase in normal serum creatinine level or >0.8 mg/dl [for infants > 4 days age] was defined as AKI. All newborns were divided into two groups: with and without AKI. Risk factors and mortality rates were compared in the 2 groups. The mortality rate of newborns with AKI was 4.5%. The other risk factors for mortality in neonates with AKI were as follows: Hyaline Membrane Disease [HMD] [P <0.03], using mechanical ventilation [P <0.041], using surfactant [P <0.04], first minute Apgar score <5, PC02 >60 mmHg [P <0.035], birth weight < 2500 g [P <0.003] and serum creatinine [SCr] level >1 mg/dl [P <0.003]. ROC Curve revealed that low birth weight was the most significant risk factor for mortality of neonates with AKI admitted in the NICU. Mortality related to AKI was associated with HMD, using mechanical ventilation, the need to surfactant use, low Apgar score, high blood PC02, high serum creatinine level, and low birth weight

comparison of CRIB, CRIB II, SNAP, SNAPII and SNAP-PE scores for prediction of mortality in critically ill neonates

Clinical Risk Index of Babies [CRIB], Score for Neonatal Acute Physiology [SNAP], an update of the Clinical Risk Index for Babies score [CRIB II] and Score for Neonatal Acute Physiology - Perinatal Extension [SNAP-PE] are scoring devices developed in neonatal intensive care units. This study reviewed these scoring systems in critically ill neonates to determine how well they could predict mortality. This prospective cohort study was conducted at the neonatal intensive care units of Mofid and Mahdieh hospitals between March 2006 and May 2009. We evaluated CRIB, CRIB II, SNAP, SNAPII and SNAP-PE score for each neonate and the final scores were then obtained. The predictive accuracy of these parameters were expressed as area under the receiver operative characteristic curve, sensitivity, specificity, positive predictive value and negative predictive value. Of 404 neonate evaluated 53% were male. Primary diagnoses were respiratory distress syndrome, gastrointestinal obstruction, sepsis, prematurity, and neuromuscular diseases. The authors detected mortality in 20.5% and found a significant difference in scoring systems between survived and death groups. The mean CRIB score in survived neonates was 2.57 +/- 3.66 and in death neonates 8.43 +/- 4.66 [p value<0.001]. We also found that the SNAP score had the highest area under the curve and the highest sensitivity, specificity, positive predictive value, negative predictive value and we had the lowest score for CRIB II. We concluded that the neonatal scoring systems could be a useful tool for prediction of mortality in NICUs and SNAP can predict the mortality better than the others

Blood pressure screening in school-aged children in Tehran

Hypertension is one of the most common diseases in the world and a major risk factor for cardiovascular, renal, and neurologic diseases. It seems that hypertension and overweight in children are a growing epidemic. The aim of this study was to investigate the prevalence of hypertension in school-aged children in Tehran. In a cross-sectional study, blood pressure and anthropometric measurements were performed on school-aged children in Tehran from 2008 to 2009. Children aged 7 to 11 years from 5 public schools in Tehran were included. Blood pressure, weight, and height measurement were performed at the school. At each screening, 3 seated blood pressure, weight, and height measurements were made and at least after 3 minutes of rest and choosing proper cuff, blood pressure was measured by a pediatric nephrologist and a pediatric assistant. A total of 425 school-aged children were included. Twenty-four percent of the primary school children had hypertension and 12% were shown to be overweight. Hypertension was more common in students of the north of Tehran in comparison to other geographic parts of Tehran. There was a significant difference in the prevalence of hypertension between girl students of north of Tehran and girls of the other parts of Tehran. We concluded that hypertension is a common problem in school-aged children. Our study re-emphasized the need for prevention and control of high blood pressure in children to manage the global diseases burden due to hypertension

Distal renal tubular acidosis and its relationship with hearing loss in children: preliminary report

In autosomal recessive distal renal tubular acidosis [DRTA], a substantial fraction of the patients have progressive bilateral sensorineural hearing loss. This coexistence is due to the mutations of a gene expressed both in the kidney and in the cochlea. The aim of this study was to assess the correlation between hearing loss and DRTA. In this study, 51 children diagnosed with renal tubular acidosis were evaluated. Diagnosis of DRTA was based on clinical manifestations and detection of normal anion gap metabolic acidosis, urine pH higher than 5.5, and positive urinary anion gap. Audiometry was performed in children with DRTA and sequencing of the ATP6V1B1 gene was done for those with sensorineural hearing loss. Twenty-seven patients [52.9%] had DRTA, of whom 51.9% were younger than 1 year old, 55.6% were boys, and 44.4% were girls. Eleven patients [40.7%] had bilateral sensorineural hearing loss, consisting of 5 of 15 boys [33.3%] and 6 of 12 girls [50.0%]. There was no correlation between hearing loss and gender. Three patients with hearing loss had mutation in the ATP6V1B1 gene [11.1% of patients with DRTA and 27.3% of patients with DRTA and hearing loss]. This study indicated that a significant percentage of the children with DRTA had sensorineural hearing loss and mutation in ATP6V1B1 gene. It is recommended to investigate hearing impairment in all children with DRTA

Diagnostic potential of urinary tumor necrosis factor-alpha in children with acute pyelonephritis

Tumor necrosis factor-alpha [TNF-alpha] is an important mediator of the inflammatory response in serious bacterial infections. The aim of this study was to evaluate the potential of urinary TNF-alpha for diagnosis of acute pyelonephritis in children. This study was conducted from March 2006 to December 2007 on children with confirmed diagnosis of acute pyelonephritis. They all had positive renal scintigraphy scans for pyelonephritis and leukocyturia. The ratios of urinary TNF-alpha to urine creatinine level were determined and compared in patients before and after antibiotic therapy. Eighty-two children [13 boys and 69 girls] with acute pyelonephritis were evaluated. The mean pretreatment ratio of urinary TNF-alpha to urinary creatinine level was higher than that 3 days after starting on empirical treatment [P = .03]. The sensitivity of this parameter was 91% for diagnosis of acute pyelonephritis when compared with demercaptosuccinic acid renal scintigraphy as gold standard. Based on our findings in children, the level of urinary TNF-alpha-creatinine ratio is acute increased in pyelonephritis and it decreases after appropriate therapy with a high sensitivity for early diagnosis of the disease. Further research is warranted for shedding light on the potential diagnostic role of urinary TNF-alpha in pyelonephritis in children

Urinary N-acetyl-beta-D-glucosaminidase as a diagnostic marker of acute pyelonephritis in children

Prompt diagnosis and localization of pyelonephritis are of great importance in children. The urinary excretion of enzymes, and in particular N-acetyl-beta-D-glucosaminidase [NAG], is considered a simple noninvasive marker for detection of renal tubular dysfunction due to pyelonephritis. This study was performed to determine the diagnostic value of urinary NAG in acute pyelonephritis. In a quasi-experimental study conducted on 72 children with confirmed pyelonephritis, we measured urinary NAG, creatinine, and NAG-creatinine ratio before and after the treatment. Diagnostic values of these parameters were evaluated by considering the patients before and after the treatment as disease-positive and disease-negative groups, respectively. The patients were 18 boys [25.0%] and 54 girls [75.0%] with a mean age of 43.0 +/- 39.0 months. The mean levels of urinary NAG were 12.20 +/- 6.14 U/L and 5.46 +/- 7.98 U/L before and after the treatment, respectively [P < .001]. The sensitivity and specificity of urinary NAG-creatinine ratio for diagnosis of pyelonephritis were 73.6% and 77.3%, respectively, with a cutoff point of 10.16 U/g [area under the curve = 0.76, 95% confidence interval, 0.67 to 0.76]. Significantly higher levels of urinary NAG were found in those who had a negative urine culture at diagnosis [8.8 +/- 10.4 U/L] compared to those with a positive urine culture [4.5 +/- 8.7 U/L]. We concluded that urinary NAG is elevated in children with pyelonephritis and it can be considered as a further criterion in the diagnosis of upper urinary tract infection

Urinary lnterleukin-8 in acute pyelonephritis of children: a before-after study

The aim of this study was to assess urinary interleukin-8 [IL-8] levels in pyelonephritis and its relation with the clinical course of the infection and of inflammatory changes detected by renal scintigraphy. In this quasi-experimental before-after study, we evaluated 91 children aged 1 to 144 months [mean 34.4 +/- 35.2 months] with pyelonephritis. Inflammatory markers including erythrocyte sedimentation rate, C-reactive protein, leukocyte count, and urinary IL-8, together with the results of ultrasonography, voiding cystourethrography, and dimercaptosuccinic acid renal scintigraphy were evaluated in these children. The ratios of urinary IL-8 to creatinine [IL-8/C] before and after the treatment were compared with each other. Urinary IL-8/C levels were significantly higher after the empirical treatment in comparison with those before the treatment [0.19 +/- 0.21 versus 0.51 +/- 0.53, P < .001]. No correlation was found between the urinary IL-8 levels and leukocyturia, urine culture results, other inflammatory markers, or findings of imaging examinations. We found high urinary IL-8 levels in children with pyelonephritis. We also documented its increasing after the treatment. We conclude that evaluation of urinary IL-8 can be a noninvasive test for diagnosis of upper urinary tract infection and its response to treatment

[Urinary tracts hereditary abnormalities]

The true incidence of renal hereditary diseases and urinary tract anomalies is difficult to ascertain. The incidence is estimated to be 3-6 in 100000 live births. Infant deaths from genitourinary anomalies are estimated to be approximately 6.3% of all causes of infant mortality. The first step to approach to a child with urinary tract anomaly is to make a specific diagnosis based on history taking and physical examination. Chromosomal abnormalities are found in approximately 10-20% of all renal anomalies. The first and the best way to evaluation of kidney and urinary tract anomalies is ultrasonography. Other laboratory and imaging methods like as voiding cystourethrography, isotope scans, intravenous urography and biochemistry and genetic testes would be useful after ultrasonography. The genetic consult is necessary in every child with renal and urinary tract anomalies. The hereditary diseases of the kidney are renal anomalies, hereditary syndromes and associations and hereditary tubular and glomerular diseases which are going to be discussed in this article

Fungal peritonitis in Iranian children on continuous ambulatory peritoneal dialysis

Fungal peritonitis [FP], causing catheter obstruction, dialysis failure, and peritoneal dysfunction, is a rare but serious complication of peritoneal dialysis. In this study, the frequency and risk factors of FP are evaluated in children who underwent peritoneal dialysis. A retrospective multicenter study was performed at the 5 pediatric peritoneal dialysis centers in Iran from 1971 to 2006, and FP episodes among 93 children were reviewed. Risk ratios were calculated for the clinical and demographic variables to determine the risk factors of FP. Ninety-three children aged 39 months on average were included in study. Sixteen out of 155 episodes of peritonitis were fungi infections, all by Candida albicans. The risk of FP was higher in those with relapsing bacterial peritonitis [P = .009]. Also, all of the patients had received antibiotics within the 1 month prior to the development of FP. Catheters were removed in all patients after 1 to 7 days of developing FP. Six out of 12 patients had catheter obstruction and peritoneal loss after the treatment and 5 died due to infection. Fungal peritonitis, accompanied by high morbidity and mortality in children should be reduced by prevention of bacterial peritonitis. Early removal of catheter after recognition of FP should be considered

Tumor markers in patients undergoing hemodialysis and kidney transplantation

Objective: To evaluate the effect of dialysis and kidney transplantation on serum levels of several tumor markers such as PSA, AFP, CA125, CA19-9, CA15-3, CEA and to compare with normal age matched controls

Methods: Between September of 2000 and July of 2001, the following tumor markers: PSA, AFP, CA125, CA19-9, CA15-3 and CEA were measured by ELISA Method in 29 hemodialyzed patients [group A] in 30 successfully transplanted patients [group B] and in 30 normal volunteers who did not present any clinical symptoms or signs of neoplasia

Results: The serum level of CEA was above the cutoff limit in 6.7% of hemodialyzed patients [group A] but was in the normal range in transplanted and control groups. The level of CEA were significantly higher in hemodialyzed patients in comparison to other groups [p<0.003]. Serum levels of AFP and PSA were not significantly different between the three groups [p=0.595 and p=0.545, respectively]. Although serum level of CA 19-9 was elevated in 3.3% of hemodialyzed and control group the differences between the three groups were not significant [p=0.507]. Serum level of CA 125 was elevated in 13.3% of group A, 13.8% of group B and 6.7% of control group [p=0.347]. Serum level of CA15-3 was elevated in 13.3%, 6.9% of group A, B and control group, respectively and the differences were not significant [p=0.156]

Conclusion: Hemodialyzed and transplanted patients show a high false positive rate of CEA, CA125 and CA15-3 and may be unreliable for monitoring of malignancies in these patients while other markers evaluated [AFP, PSA and CA 19.9] appear to maintain their specificity in these situations