Elevated serum levels of Vitamin D in infants with urolithiasis.

INTRODUCTION: The pathophysiology of urolithiasis in infancy is not well known. The aim of this study was to investigate whether infants with urolithiasis have higher serum levels of vitamin D, as a possible risk factor for urolithiasis, compared to infants without urinary calculi. MATERIALS AND METHODS: In this case-control study, 36 infants with urolithiasis (age range, 2.5 to 24 months) were enrolled as well as 36 age- and sex-matched infants without urolithiasis. Random urine samples were tested for calcium, phosphorous, oxalate, citrate, uric acid, sodium, potassium, magnesium, and creatinine levels, and also nitroprusside test was done on the samples. Serum levels of potassium, urea nitrogen, creatinine, 25-hydroxyvitamin D3, parathyroid hormone, calcium, phosphorous, and uric acid were measured in all of the infants with urolithiasis. Serum levels of 25-hydroxyvitamin D3 were also measured in the control group. RESULTS: Serum levels of 25-hydroxyvitamin D3 were significantly higher in the infants with urolithiasis than in the controls (33.85 ± 14.78 ng/mL versus 18.26 ± 7.43 ng/mL, P < .001). Nine infants in the urolithiasis group (25%) were found to have hypercalcemia; 3 of these cases also had hypervitaminosis D. Hypercalciuria was detected in 10 infants with urolithiasis (27.8%), hypocitraturia in 6 (16.7%), hypomagnesiuria in 3 (8.3%), and hyperoxaluria in 1 (2.8%). Nineteen infants with urolithiasis had at least one metabolic disorder. CONCLUSIONS: High serum levels of vitamin D may play an important role in the pathogenesis of urolithiasis in infants with hypercalcemia. We recommend evaluation of vitamin D levels in these infants.

Urinary tract infection after kidney transplantation in children and adolescents.

INTRODUCTION: Urinary tract infection (UTI) is common after pediatric kidney transplantation. The purpose of this study was to evaluate the prevalence of UTI and its risk factors in children and adolescents with kidney transplantation in Shiraz Transplant Center. MATERIALS AND METHODS: All children with kidney transplantation from 1992 to 2008 who were under regular follow-up were included in this retrospective study. Confirmed episodes of UTI after the 1st month of kidney transplantation were reviewed. RESULTS: Of the 216 patients younger than 19 years at the time of transplantation, 138 were included. The mean age at the time of kidney transplantation was 13.6 ± 3.5 years. Urinary tract infection was documented in 24 patients (15 girls and 9 boys), of whom 12 experienced 1 episode, 4 had 2 episodes, and 8 had more than 2 episodes, during a median follow-up period of 54 months. Of the patients with UTI, 14 (58%) had urinary reflux-obstruction disorders as the primary kidney disease, 6 (25%) had suffered hereditary diseases, 3 (12.5%) had glomerular disease, and 1 (4.5%) had a urinary calculus. Occurrence of UTI was not significantly different among children with different primary kidney disease (P = .22). Despite using prophylactic antibiotics after the 1st month of kidney transplantation in all 5 patients with neurogenic bladder, they all experienced recurrent UTI. CONCLUSIONS: Despite discontinuation of antibiotic therapy, UTI was uncommon in children after the first month of transplantation. Two significant risk factors for UTI were female gender and neurogenic bladder in this transplant population.

Outcome of renal transplantation in children: a multi-center national report from Iran.

The outcome of pediatric renal transplantation was previously reported by a single-center study at the year 2006. Therefore, we aimed to evaluate and report the characteristics and outcome of renal pediatric renal transplantation in a multi-center nationwide study. In this nationwide report, medical records of 907 children (≤18yr) with renal transplantation in eight major pediatric transplant centers of Iran were recorded. These 907 patients received a total of 922 transplants. All children who failed to follow-up were excluded. Rather than baseline characteristics, graft and patient outcomes were considered for survival analysis. For further analysis, they were divided into two groups: patients who had graft survival time more than 10yr (n=91) and the ones with graft survival time of equal or less than 10yr (n=831). Of 922 recipients, 515 (55.8%) were boys and 407 (44.2%) were girls with the mean age of 13.10 (s.d.=3.54) yr. DGF and AR were occurred in 10% and 39.5% of the transplanted children, respectively. Transplantation year, dialyzing status before transplantation, DGF, and AR were significant enough to predict graft survival in cox regression model (overall model: p<0.001). Nowadays, there is a successful live donor pediatric renal transplantation in Iran. Graft survival has improved in our recipients and now the graft survival rates are near to international standards.

Bone mineral disorders in pediatric and adolescent renal transplant recipients.

Incomplete resolution of abnormalities of mineral metabolism associated with CRF results in the relatively high prevalence of ROD in pediatric kidney recipients. This non-randomized, cross-sectional, and analytic-descriptive study on bone density, vitamin D, and mineral metabolism was performed in 57 children and adolescents who had received a total of 60 renal allografts in Shiraz, Iran. The height and weight of the patients were measured; their serum calcium (Ca), phosphorus (P), Alk-P, PTH, 25(OH)-vitamin D(3), BUN, creatinine, and electrolyte levels were analyzed, and a complete blood count was performed. In addition, standard radiologic bone assessments, which included conventional left hand-wrist radiography and bone mineral densitometry by the DXA technique, were carried out. Special pediatric software was used for age-related interpretation of the Z-scores of BMD. SPSS(®) software (version 15) was used for statistical analyses. We studied 57 patients (27 males [47.4%]) with a mean age of 18.7 ± 4.25 (9-27) yr and a mean age at transplantation of 13.1 ± 3.46 (4.5-20) yr. They had a post-transplantation follow-up of 67.1 ± 33.8 (6-132) months, and all had well-functioning allografts at enrollment. The mean height age of the patients was 11.9 ± 1.8 (6-15.5), and the mean bone age was 15.6 ± 3.3 (7-19) yr, which corresponded to mean height-age and bone-age retardations of 5.7 ± 2.3 (0.5-10.5) and 1.22 ± 1.47 (0-7) yr, respectively. Hyperphosphatemia and hypercalcemia were each found in nine patients (15.8%), hypophosphatemia in five (8.8%), and hypocalcemia in none of the patients. Seven out of 57 patients (12.3%) had a (Ca×P) product of more than 55 mg(2)/dL(2). Hyperparathyroidism was found in 27 (47.3%) and vitamin D(3) deficiency in four (7%) of the cases. The serum level of Alk-P was higher than the age-related normal range in 20 patients (35%). Left hand-wrist radiography showed no radiologic sign of ROD in any patient. The mean BMD Z-score was -1.77 ± 1.13 (-4.2-1.1) for the lumbar spine and -1.64 ± 0.89 (-3.9 to 1.9) for the femoral neck. "Stepwise backward regression" revealed a significant inverse correlation between the serum level of PTH and the GFR of the transplanted kidney; this correlation was independent from the influence of other variables such as Ca, P, and Alk-P (p = 0.011, ß = -1.556). Bone age and height age both showed significant correlations with age at transplantation and serum levels of P (p < 0.001), but only bone age had a meaningful correlation with Alk-P (p = 0.036). The BMD Z-scores showed statistically meaningful correlations with the serum level of Alk-P, which were independent from the influence of other variables such as Ca, P, and PTH (p ≤ 0.002). Our study revealed a relatively high prevalence of bone mineral disorder in pediatric kidney recipients, which suggests the need for a routine program for periodic screening of these patients to facilitate early diagnosis of either persistent or evolving manifestations of disturbed mineral metabolism, especially ROD.

Gouty arthritis in a 15-year-old girl with Bartter's syndrome.

A 15-year-old girl, a known case of Bartter's syndrome (BS) for 7 years, developed severe pain in her right knee and right and left ankle. Her older sister had BS and developed end-stage renal disease (ESRD) at the age of 14 years. Her serum uric acid was 12.6 mg/dL, 6 months ago, and 15.4 mg/dL in her recent lab data. Hyperuricemia and gouty arthritis are commonly seen in adults with BS, but to our knowledge there is no report of gouty arthritis in pediatric literature.

Subclinical atherosclerosis and related risk factors in renal transplant recipients.

Long-term survival after successful renal transplantation is shortened by cardiovascular disease. Cardiovascular disease is a main cause of morbidity and death among children and young adults after renal transplantation. The aim of our study was to measure the carotid intima media thickness (cIMT) and determine its relationship to the risk factors for early arteriopathy in renal transplant recipients. Sixty-six stable renal transplant patients (36 female and 30 male), 7-25 years of age (mean 18.3 +/- 4.5 years) were enrolled in this study. The cIMT was measured by high-resolution B mode ultrasonography in multiple projections. The results were correlated with clinical and paraclinical parameters, including age, gender, body mass index (BMI), blood pressure, glomerular filtration rate (GFR), duration of dialysis, duration of chronic kidney disease (CKD), post-transplantation interval, calcium-phosphate (CaxP) product, cumulative dose of Ca-based P binder and calcitriol, lipid profile, uric acid, and cyclosporine level. The mean post-transplantation follow-up period was 64 +/- 40 months. The mean cIMT standard deviation score (SDS) of the patients and the control group was 0.60 +/- 0.81 mm (range -1.10 mm to 2.75 mm) and -1.25 +/- 0.95 mm (range -3.23 mm to 0.26 mm), respectively. Renal transplant recipients had a significantly greater cIMT than that of the controls (P < 0.001). Among several risk factors, there were positive correlations between cIMT SDS and gender, and cumulative dose of calcitriol (P = 0.02 and P = 0.02, respectively). In conclusion, subclinical atherosclerosis is present in young transplant recipients. Non-invasive monitoring of cIMT in renal transplant patients for the detection of early vascular lesions might be of value in preventing cardiovascular disease. Further studies are needed to see if proper monitoring of vitamin D therapy before and after transplantation could be helpful in the prevention of arteriopathy in renal transplant recipients.

The outcome of Iranian children on continuous ambulatory peritoneal dialysis: the first report of Iranian National Registry.

BACKGROUND: Continuous ambulatory peritoneal dialysis is not a very common modality to treat Iranian children with end-stage renal disease; however, there is sometimes no choice but to offer this therapy to salvage the patient. Obviously, promotion in each program needs re-evaluation to find the pitfalls. Therefore, a nation-wide survey on pediatric continuous ambulatory peritoneal dialysis was conducted to find the cause of death or termination of dialysis. METHODS: All children, younger than 14 years old, treated by continuous ambulatory peritoneal dialysis in nine main pediatric nephrology wards in Iran between 1993 and 2006 were included in this historical cohort study. Patient and technique survival rates were determined. Kaplan-Mayer and Cox-regression analysis were used to compare the survival. 2 x 2 table was used to calculate the risk ratio. A P<0.05 was considered significant. RESULTS: One hundred twenty children with a mean age of 47.6 months were on continuous ambulatory peritoneal dialysis. The most frequent cause of renal failure was hereditary-metabolic-cystic disease. One hundred eighty-two peritoneal dialysis catheters were inserted surgically. The median first catheter exchange was 0.74 year (95%CI: 0.5 - 0.98). The most frequent cause of catheter replacement was catheter outflow failure due to displacement, adhesion, and infection (persistent peritonitis or tunnel infection). The mean patient survival was 1.22 years (95%CI: 0.91 - 1.53). The mortality rate was 55% before 1997, and 60% between 1998 and 2001, which declined to 23% after 2002 (P<0.05). Young age (<24 months) was the only independent factor that predicted mortality (P<0.05). The outcome of children was as follows: recovery of renal function (6.7%), renal transplantation (8.3%), switch to hemodialysis (16.7%), still on continuous ambulatory peritoneal dialysis (23.3%), death (43.3%), and lost to follow-up (1.7%). CONCLUSION: The mortality is still high among Iranian children on peritoneal dialysis. Young age is the most important factor influencing on survival and mortality.

Gastrointestinal evaluation in pediatric kidney transplantation candidates.

INTRODUCTION: Our aim was to determine the frequency of peptic ulcer and Helicobacter pylori infection by gastrointestinal evaluations in pretransplantation phase in children with end-stage renal disease (ESRD). MATERIALS AND METHODS: Twenty-four children with ESRD (13 girls and 11 boys) with a mean age of 14.7 +/- 3.4 years on maintenance hemodialysis were included in this study. Upper gastrointestinal endoscopies were performed and 4 gastric, antral, and duodenal biopsy specimens were obtained for urease test and histological study. Serum gastrin levels were measured in all patients, too. A control group was chosen to compare the rate of H pylori infection between children with ESRD and healthy children. RESULTS: Gastrointestinal symptoms were present in 16 (66.7%) of 24 patients. Seventeen (70.8%) patients had abnormal upper gastrointestinal endoscopic findings. Infection with Helicobacter pylori was detected in 16 patients and 5 healthy children (66.7% versus 20.0%, P < .001). The frequency of dyspeptic symptoms was not different significantly between uremic patients with and without H pylori infection (P = .67). The same results were found regarding the upper gastrointestinal abnormalities found by endoscopy (P = .65). Oral alkalizing supplement was received by 63% of symptomatic and 80% of asymptomatic patients. Serum gastrin levels were significantly higher in infected patients than in noninfected patients with H pylori (P < .001). CONCLUSIONS: We found a significant number of patients with peptic ulcer diseases, H pylori infection, and secondary hypergastrinemia. This study showed that clinical symptoms are not a reliable predictor of gastrointestinal problems and this is more confusing in patients who received alkalizing solutions.

A neglected case of renal tubular acidosis.

In this report, we present a case of a child with distal renal tubular acidosis, severe failure to thrive and profound rickets, who was only 7.8 Kg when presented at 6 years of age. His response to treatment and his follow-up for four years is discussed. Although failure to thrive is a common finding in renal tubular acidosis but the physical and x-ray findings in our case were unique.

Fungal peritonitis in Iranian children on continuous ambulatory peritoneal dialysis: a national experience.

INTRODUCTION: 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. MATERIALS AND METHODS: 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. RESULTS: 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. CONCLUSIONS: 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.

Spectrum of In-patient Renal Diseases in Children "A Report from Southern part Islamic Republic of Iran".

This survey was performed on children with renal diseases admitted to Shiraz Pediatric Nephrology Unit from October 1993 to March 2000. There was a total of 1358 children, of whom 709 (52%) were boys, with age range of 1 month to 16 years and a mean of 6.5 +/- 4.7 years. Thirty percent of children were below age of 2 years. Admission diagnosis was acute nephritis in 312 (23%) patients, urinary tract infection in 259(19.1%), nephrotic syndrome in 252 (18.6%), chronic renal failure in 202 (14.9%), urologic problems in 101 (7.5%), acute renal failure in 99 (7.3%), metabolic disorders in 47 (3.5%) and hypertension in 39 (2.9%). Acute poststreptococcal nephritis was the most common disease in the acute nephritis group. Minimal change nephrotic syndrome was the most common in the nephrotic syndrome group (64.2%). Chronic renal failure was mainly due to congenital urological malformations (46%). Acute renal failure (ARF) was caused mainly by gastroenteritis. There were six cases of ARF due to scorpion sting and 12 cases due to various malignancies and associated tumorlysis syndrome. Persistent hypertension was caused mainly by reflux nephropathy (50%). We conclude that the patterns of renal diseases found in the Iranian children were similar to those reported from other developing countries with predominance of infection related diseases.