Andrew R. Rosenberg

Evaluation of acute urinary tract infection in children by dimercaptosuccinic acid scintigraphy: a prospective study.

A prospective study examining the incidence of dimercaptosuccinic acid (DMSA) abnormalities in children at the time of acute urinary tract infection, the progression of these abnormalities following treatment and their correlation with the presence of vesicoureteral reflux is reported. DMSA scans performed within 72 hours of presentation in 65 previously healthy children with acute urinary tract infection were abnormal in 34 (52%). The scan appearances of 30 of 36 (83%) initially abnormal kidneys improved or became normal on the repeat DMSA study performed at 3 to 6 months after the acute urinary tract infection. A cystogram demonstrated significant vesicoureteral reflux in 11 of 45 cases (24%). Of these 11 cases 10 had abnormal DMSA studies and 1 had dilated upper tracts on ultrasound. Several conclusions may be drawn from our study. The incidence of DMSA abnormalities at the time of acute urinary tract infection is high but these abnormalities tend to resolve with time. An abnormal DMSA study at the time of urinary tract infection identifies most children with significant vesicoureteral reflux, and in our series a combination of ultrasound and DMSA identified all cases. This study may have major implications for the clinical investigation of children with urinary tract infection.

Isotonic is better than hypotonic saline for intravenous rehydration of children with gastroenteritis: a prospective randomised study

Aims: To determine whether the risk of hyponatraemia in children with gastroenteritis receiving intravenous (IV) fluids is decreased by the use of 0.9% saline. Methods: A prospective randomised study was carried out in a tertiary paediatric hospital. A total of 102 children with gastroenteritis were randomised to receive either 0.9% saline + 2.5% dextrose (NS) or 0.45% saline + 2.5% dextrose (N/2) at a rate determined by their treating physician according to hospital guidelines and clinical judgement. Plasma electrolytes, osmolality, and plasma glucose were measured before (T0) and 4 hours after (T4) starting IV fluids, and subsequently if clinically indicated. Electrolytes and osmolality were measured in urine samples. Results were analysed according to whether children were hyponatraemic (plasma sodium <135 mmol/l) or normonatraemic at T0. Results: At T0, mean (SD) plasma sodium was 135 (3.3) mmol/l (range 124–142), with 37/102 (36%) hyponatraemic. At T4, mean plasma sodium in children receiving N/2 remained unchanged in those initially hyponatraemic (n = 16), but fell 2.3 (2.2) mmol/l in the normonatraemic group. In contrast, among children receiving NS, mean plasma sodium was 2.4 (2.0) mmol/l higher in those hyponatraemic at baseline (n = 21) and unchanged in the initially normonatraemic children. In 16 children who were still receiving IV fluids at 24 hours, 3/8 receiving N/2 were hyponatraemic compared with 0/8 receiving NS. No child became hypernatraemic. Conclusions: In gastroenteritis treated with intravenous fluids, normal saline is preferable to hypotonic saline because it protects against hyponatraemia without causing hypernatraemia.

The Detection of Reflux Nephropathy in Infants by 99 mtechnetium Dimercaptosuccinic Acid Studies

Dimercaptosuccinic acid (DMSA) studies were performed in 113 infants less than 1 year old at risk of renal scarring. Of these patients 86 presented with urinary tract infection and 27 were asymptomatic. A voiding cystourethrogram was performed in all cases and excretory urography (IVP) was done in 99. More abnormalities were detected by DMSA study when compared to scars on IVP. When both studies were abnormal there was an excellent correlation on a site by site basis. Fever or systemic disorder was not a reliable sign to determine whether there was upper tract involvement with infection. The incidence of DMSA abnormalities in infants increased with high grade vesicoureteral reflux and decreased with low grade reflux. There was no significant difference in the incidence of abnormal kidneys between the infected and noninfected groups, suggesting that renal scarring may occur with sterile reflux.

Waiting time and outcome of kidney transplantation in adolescents.

Background. The major cause of late graft failure in adolescent kidney transplant recipients is thought to be nonadherence with medications. Delaying transplantation in adolescents may lead to improved adherence but at the cost of longer time on dialysis. To determine if waiting time on dialysis is a risk factor for graft survival in adolescents, we compared the outcomes of kidney transplants according to age and time on dialysis. Methods. We analyzed data from the Australian and New Zealand Dialysis and Transplant Registry on 2,739 primary kidney transplants performed between 1980 and 2004 in recipients less than 30 years old. Outcomes according to age at transplantation and waiting time were analyzed by Kaplan-Meier curves, log-rank tests, and Cox proportional hazard tests. Results. Overall five- and 10-year graft survival rates were significantly worse in adolescents (65% and 50%, respectively) compared to recipients aged two to 10 years (74% and 58%) and 20 to 29 years (72% and 57%). Waiting time on dialysis was an independent risk factor for failure of living donor grafts in adolescents (hazard ratio 0.53, P=0.03). Five- and 10-year graft survival of preemptive grafts in adolescents were 82% and 70%, respectively, which were similar to survival rates of preemptive grafts in other age groups. Conclusions. Reduced graft survival rates in adolescent recipients are not seen after preemptive transplants. Preemptive grafts are associated with a 50% reduction in the risk of graft failure. Delaying transplantation in adolescents may expose them to increased risk of poorer outcomes.

HBV associated nephrotic syndrome: resolution with oral lamivudine

A 6 year old boy presenting with a five month history of fever, lethargy, and anorexia, was found to have hepatitis B associated membranous glomerulonephropathy and nephrotic syndrome. After two months treatment with oral lamivudine, his proteinuria cleared and serum albumin and aminotransferases normalised, associated with disappearance of hepatitis B e antigen (HBeAg) and appearance of anti-HBeAg antibodies. After 12 months, without side effects, lamivudine was discontinued. He remains well 11 months off treatment.

BK viral infection in an Australian pediatric renal transplant population

Abstract: BK virus (BKV) is recognized as a significant cause of renal allograft dysfunction in adults, and there is growing awareness of its importance in the pediatric population. Eighteen pediatric renal transplant recipients and 18 age‐matched controls were prospectively studied. Anti‐BKV immunoglobulin G (IgG) and IgM titres were assayed in all subjects at entry to the study. Polymerase chain reaction (PCR) for BKV DNA was performed on urine and serum at entry, and prospectively tested again at 4, 8 and 12 months. Mean age ± s.d. of transplant recipients and controls was 14.6 ± 3.3 and 13.9 ± 0.33 yr respectively [not significant (NS)]. Transplant patients were studied at a mean time of 5.6 ± 4.2 yr post‐transplant. 56% of transplant patients and 39% of controls were seropositive (+ve BKV IgG) (NS). Plasma BKV PCR was positive in one transplant patient (who also had positive urine PCR) and in none of the controls. The prevalence of positive urine PCR in transplant patients was greater than in controls (33% vs. 0%, p = 0.02). Positive urine BKV PCR was more commonly found in patients treated with mycophenolate than azathioprine (p = 0.04). We conclude that the prevalence of BKV seropositivity and viral activation in this Australian pediatric renal transplant population is similar to that reported in adult and pediatric populations in other countries. BK viruria was more common in children with greater immunosuppression, suggesting that this group is at higher risk of BKV induced nephropathy.

The relationship between serum creatinine, serum cystatin C and glomerular filtration rate in pediatric renal transplant recipients: A pilot study

Abstract: Serum cystatin C more accurately reflects glomerular filtration rate (GFR) in pediatric renal transplant recipients than serum creatinine. Nineteen pediatric renal transplant recipients, 15 male and 4 female, ranging in age from 8.35 yr to 19.06 yr (median 13.52 yr), were enrolled in the study over an 18‐month period. Twenty‐eight measurements of 99mTc‐DTPA GFR were compared with simultaneous measurements of serum cystatin C and Cr. Linear regression analysis, Pearson correlation coefficients and analysis of variance (anova) were used to determine the relationship between creatinine, cystatin C and GFR. The correlation coefficients (R2) for the relationship of 1/Cr to DTPA‐GFR and for 1/cystatin C to DTPA‐GFR were 0.63 and 0.58, respectively. There was no significant difference between serum cystatin C and serum creatinine as markers of GFR. Serum cystatin C, which costs more to measure than serum creatinine, offers no advantage in monitoring the renal function of pediatric renal transplant recipients.

Post‐streptococcal glomerulonephritis in Sydney: A 16‐year retrospective review

Aim:  Post‐streptococcal glomerulonephritis (PSGN) is a frequent cause of acute nephritis in children. Numerous studies have described PSGN in high‐risk populations yet few data describing PSGN in a low‐incidence population exist. This study aimed to describe the epidemiology, clinical manifestations, diagnosis, complications and outcomes of PSGN in an urban Australian population.

Effects of Growth Hormone Treatment for Short Stature on Calcium Homeostasis, Bone Mineralisation, and Body Composition

We investigated the effect of growth hormone (GH) treatment on mineral and vitamin D homeostasis, bone mineralisation, and body composition in short-statured children without GH deficiency (GHD). 11 children received GH (0.50 +/- 0.08 IU/kg/week) for 24 weeks. 1,25-Dihydroxyvitamin D3 levels (mean +/- SD in pmol/l) rose from a baseline of 73.7 +/- 39.2 to 114.0 +/- 32.7 at 8 weeks (p < 0.05) and 111.9 +/- 39.7 at 24 weeks (p < 0.01). Body composition evaluation using dual-energy X-ray absorptiometry revealed increased lean tissue mass and a reduction in fat tissue. As a percentage of total body mass, fat decreased from 19.0 +/- 11.8% at baseline to 17.3 +/- 11.5% at 8 weeks (p < 0.005) and 16.8 +/- 11.5% at 24 weeks (p < 0.05). L2-L4 bone mineral density was 0.637 +/- 0.155 g/cm2 at baseline and 0.666 +/- 0.160 g/cm2 at 24 weeks (NS). We conclude that recombinant human GH treatment of short children without GHD has significant effects on vitamin D homeostasis and body composition.

Renal effects of growth hormone. II. Electrolyte homeostasis and body composition

Growth hormone (GH), either directly or through insulin-like growth factor-1 (IGF-1), has a wide spectrum of physiological and renal effects. This review concentrates on the effects of GH (derived from either pituitary or recombinant technology) and IGF-1 in three main areas: (1) sodium and water homeostasis; (2) calcium and phosphate balance, bone density and interactions with mineral regulating hormones; (3) fat and lean body mass. Observations of physiological changes in states of GH deficiency and excess in humans and animal models are presented. The lack of long-term toxicological data indicates that GH treatment for short stature in non-GH deficient children, with or without renal disease, should proceed with caution.