The use of plasma creatinine concentration for estimating glomerular filtration rate in infants, children, and adolescents

Randomised multicentre study of a low-protein diet on the progression of chronic renal failure in children. European Study Group of Nutritional Treatment of Chronic Renal Failure in Childhood

BACKGROUND

Some studies have suggested that a low-protein diet slows the deterioration of renal function in patients with chronic renal failure (CRF). The effects of a low-protein diet on renal function and growth, have not been assessed in a large, prospective randomised trial in children with CRF.

METHODS

A 2-year prospective, stratified, and randomised multicentre study recruited 191 patients aged 2-18 years. After a run-in period of at least 6 months, patients were stratified into either a progressive or non-progressive category based on the change in creatinine clearance in this period. The patients were also stratified into three renal-disease categories and then randomly assigned to a control or diet group. In the diet group, the protein intake was the lowest, safe WHO recommendation--i.e., 0.8-1.1 g/kg daily adjusted for age. All patients were advised to have a calorie intake of at least 70% of the WHO recommendations. Glomerular filtration rate (GFR) was measured every 2 months by creatinine clearance; dietary compliance was checked by urinary urea-nitrogen excretion and dietary diaries (weighing method). 112 patients completed an optional third year of the study.

FINDINGS

The low-protein diet did not affect growth. However, there was no effect of diet on the mean decline in creatinine clearance over 2 years (diet vs control: progressive group -9.7 [SD 8.0] vs -10.7 [11.8] mL/min per 1.73 m2; non-progressive group -2.5 [7.5] vs -4.3 [10.0] mL/min per 1.73 m2). Patients classified as having progressive disease were older and had a lower creatinine clearance and a higher blood pressure at randomisation, and had a greater decrease in creatinine clearance than non-progressive patients. On multivariate regression analysis proteinuria (partial R2 = 0.259) and systolic blood pressure (partial R2 = 0.087) were independent predictors of the change in GFR. Similar results were found after the study was extended for a third year.

INTERPRETATION

A low-protein diet for 3 years did not affect the decrease in renal function in children with CRF. Proteinuria and blood pressure explain a large part of the variability of, and may be causally related to the decline in the GFR.

Controlled pilot study of rapid amphotericin B infusions

This pilot study compared the toxicity of a one hour with a four hour amphotericin B infusion in children. There were more severe chills in the former group on the first day of infusion, and more hypotension in the latter group over the study duration.

Evaluation of antibiotic-induced nephrotoxicity in preterm neonates by determining urinary alpha 1-microglobulin

alpha 1-Microglobulin (alpha 1-m, protein HC), a relatively low molecular weight protein of about 31,000 daltons, was measured in urine of three groups of 34 preterm neonates: group A consisted of 9 healthy preterm neonates; groups B (n = 13) and C (n = 12) consisted of preterm neonates with suspected or confirmed bacterial infections. Immediately after birth, all group B neonates were treated with ampicillin and aztreonam in combination, and all group C neonates were treated with oxacillin and amikacin in combination. To optimize amikacin administration, computerized individually tailored doses were administered. Urine samples were obtained from a short collection in sterile bags on the 1st, 4th, and 7th day after delivery in all infants. Urinary alpha 1-m concentrations were measured by a turbidimetric method (latex agglutination photometric immunoassay) and results were expressed as a ratio to urinary creatinine. In group A, urinary alpha 1-m concentrations were stable after birth. In group C, alpha 1-m excretion increased immediately within the 1st day of treatment, and over the 1st week of life urinary alpha 1-m levels were significantly higher than in group A (P = 0.033). These data support the conclusion that amikacin administration was the most important factor inducing renal tubular dysfunction in the neonates of group C.

Pharmacokinetics of bumetanide in critically ill infants

OBJECTIVE

Define the pharmacokinetics of bumetanide after single intravenous doses in volume-overloaded critically ill infants.

METHODS

A prospective, open-label study was carried out in a group of 58 infants aged 0 to 6 months who required diuretic therapy. Each patient received a single dose of intravenous bumetanide. Doses selected in sequential order ranged from 0.005 to 0.10 mg/kg. Hematologic and serum chemistry studies were performed before and at 6 and 24 hours after bumetanide administration. Determinations of urine volume and chemistries were performed before (collected from -2 to -4 hours to time 0) and at 1, 2, 3, 4, 6, and 12 hours after bumetanide dosing. Serum samples collected at time 0 and at 5, 15, 30, 60, 120, 180, 240, 360, and 480 minutes and urine collected at time 0 and at 0 to 1, 1 to 2, 2 to 3, 3 to 4, 4 to 6, and 6 to 12 hours were analyzed for bumetanide concentration. Data were evaluated by standard noncompartmental pharmacokinetic techniques.

RESULTS

Peak serum bumetanide concentrations occurred at 5 minutes after bumetanide administration. Area under the curve and peak serum bumetanide concentrations showed linear increases over the twentyfold dose range; whereas beta volume of distribution, volume of distribution at steady state, clearance, renal clearance, half-life, and mean residence time values were independent of dose. Peak urinary excretion rates of bumetanide increased linearly with increasing doses. The mean percent of bumetanide recovered in the urine from 0 to 12 hours was 40% +/- 15% of the administered dose.

CONCLUSIONS

Distribution and elimination kinetics of bumetanide were similar in all patients. Elimination kinetics were first order over the dose range of 0.005 to 0.10 mg/kg. Pharmacokinetic parameter estimates (beta volume of distribution, volume of distribution at steady state, clearance, renal clearance, half-life, and mean residence time) were independent of the dose of bumetanide administered. Single doses of bumetanide up to 0.10 mg/kg appear to be well tolerated in acutely ill volume-overloaded infants aged 0 to 6 months.

Renal magnesium handling in infants and children

Renal handling of magnesium (Mg) has been incompletely studied during infancy and childhood due to the difficulty, until recently, of measuring the diffusible fraction of plasma Mg. In the present investigation this methodology has been used to assess Mg homeostasis in 45 healthy infants, aged 1 to 12 months, and in 63 healthy children, aged 1 to 15 years. When compared to children, infants had significantly higher plasma values (mean +/- SD) for both total (0.76 +/- 0.08 versus 0.70 +/- 0.06 mmol l-1; p < 0.001) and ultrafilterable Mg (0.51 +/- 0.07 versus 0.49 +/- 0.04 mmol l-1; p < 0.05). No significant correlations were present between values of plasma Mg and plasma concentrations of calcium, creatinine, total protein or albumin. The ratio Umg/Ucr, calculated in the second morning urine (median, 3rd-97th centiles), was also significantly higher during infancy (0.023, 0.009-0.07 versus 0.015, 0.006-0.04; p < 0.001). On the contrary, fractional excretion of Mg (median, 3rd-97th centiles) was identical in both age groups and did not correlate significantly with age (infants: 3.2, 1.0-7.8%, children 3.4, 1.6-8.1%; p = NS). During a Mg infusion, carried out in six children, we could establish an approximative value for renal Mg threshold (plasma ultrafilterable Mg = 0.50 mmol l-1) close to that found in adults. These results indicate that no functional immaturity is present during infancy for renal tubular reabsorption of Mg and that the high Umg/Ucr ratio observed in this age group is a phenomenon not dependent on a higher urinary Mg excretion but probably related to a lower urinary creatinine excretion per unit of lean body mass.

Progressive glomerular toxicity of ifosfamide in children

Glomerular toxicity following ifosfamide (IFO) is not as well recognized as renal tubular damage. Following a case of ifosfamide-induced renal failure with histological evidence of glomerular changes, we undertook a retrospective study of all IFO-treated children to assess the extent and severity of its glomerular toxicity and to identify possible predisposing factors. Thirty-seven children with a follow-up of 6 months or more from the end of chemotherapy were studied. They were a median of 10.8 years old (range 3.25-18.5), had received a median of 54 g/m2 (range 9-135) of IFO, and had a median follow-up of 29 months (range 6-68). The criteria to identify glomerular dysfunction were raised plasma creatinine (Pc) values on two occasions or a low glomerular filtration rate (GFR) measured by Tc-99-DTPA clearance. Detailed assessment was carried out to identify other nephrotoxic influences in these children. Subjects in whom glomerular dysfunction could be causally linked to IFO were compared with the rest of the group for a variety of predisposing factors. Of eight children with glomerular dysfunction, two had other nephrotoxic influences and were excluded from further analysis. In six (17.1%) children, glomerular dysfunction appeared to be causally linked to IFO. Their median GFR was 61.9 ml/min/1.73 m2(range 33-85) and Pc was 123 mumol/l (range 85-216). Five of the six had normal glomerular function at the end of therapy and the raised Pc values were first noted 19, 21, 26, 29, and 36 months later. Children with glomerular toxicity had a significantly longer median follow-up (41.5 vs. 19 months; P = 0.04) than the rest of the group, suggesting late onset of this problem. They were older at the time of the study and had received nearly twice the dose of IFO, though the differences in age and dose did not reach statistical significance. The earliest signs of renal toxicity were seen in the index case, who had had prior nephrectomy. All affected children had coexistent and preceding tubular toxicity. The inadequacies of tests commonly used to assess glomerular function and the possibility of underestimation of dysfunction are discussed. Glomerular dysfunction following IFO is poorly recognized and evidence from this study of its later onset and progressive nature is a cause for concern. The index case is described with histological findings.

Population pharmacokinetics of ganciclovir in newborns with congenital cytomegalovirus infections. NIAID Collaborative Antiviral Study Group

The population pharmacokinetics of ganciclovir was investigated in a group of 27 newborns with symptomatic congenital cytomegalovirus infection by nonlinear mixed-effects modeling analysis. Individual characteristics including approximated creatinine clearance from serum (ASCC) and body weight (WGE) were identified to significantly influence total clearance from plasma (CL) and the apparent total volume of distribution (V) of ganciclovir, respectively. The regression equations used to model these relationships were expressed as CL (in liters per hour) = 0.262 + (0.00271 x ASCC) and V (in liters) = 0.627 + (0.437 x WGE). By using this model, typical values of the pharmacokinetic parameter CL and V were 0.428 +/- 0.079 liters/h and 1.773 +/- 0.320 liters, respectively. Upon validation with a larger number of newborns, this model should allow for the definition of possible relationships between the pharmacokinetic disposition of ganciclovir and pharmacodynamic events in neonates.

Induction of an experimental Fanconi syndrome in mice: its effect on the glomerular filtration function studied by 99mTc-DTPA

An experimental mice model of maleate (MAL)-induced Fanconi syndrome has been used to test 99mTc-DTPA ability to detect hampered glomerular filtration rate (GFR) early in drug-induced Fanconi syndrome. In fact, declining GFR has been reported both in idiopathic and acquired Fanconi syndrome. The above MAL model shows urine biochemistry changes similar to those reported in patients suffering from Fanconi syndrome. Moreover, biodistribution study and whole-body autoradiographies performed after IV injection of 99mTc-DTPA in MAL and control mice show significantly delayed pharmacokinetics of the above radiopharmaceutical in a MAL dose-dependent effect. After administration of a MAL dose of 6 mM/kg BW, the 5-min biodistribution of 99mTc-DTPA, a radiopharmaceutical freely excreted by glomerular filtration, is significantly changed in all organs. In blood of MAL mice, 27.62 +/- 2.86% of the injected dose is still circulating compared to 13.67 +/- 1.22% of the injected dose in control mice, and only 1.37 +/- 0.31% of the injected dose has been excreted in urine of MAL mice compared to 24.66 +/- 4.12% of the injected dose in urine of control mice. The obtained results suggest that 99mTc-DTPA may be efficient both in the early detection of abnormal GFR in acquired Fanconi syndrome after application of a nephrotoxic treatment, and in the follow-up of patients in recovery phase after discontinuation of the therapy.

Developmental renal physiology of the low birth weight pre-term newborn

PURPOSE

The remarkable growth of the kidney and the rapid changes in renal function in the second half of gestation and early postnatal period are discussed.

MATERIALS AND METHODS

Adaptation to the extrauterine environment involves immediate postnatal natriuresis that is prolonged in the pre-term neonate, followed by the sodium retention necessary for growth. Glomerular filtration rate increases throughout the postnatal period, and it is modulated by the renin-angiotensin system and prostaglandins. Because of this, the fetus and neonate are particularly susceptible to renal injury following the administration of angiotensin converting enzyme inhibitors or nonsteroidal anti-inflammatory drugs. Renal tubular function in the neonate is characterized by reduced renal concentration and acidification ability, which can be further compromised by obstructive uropathy. Urine calcium excretion is high in the neonate, which can be aggravated by calciuric drugs, such as furosemide and glucocorticoids.

RESULTS

Reduced renal mass results in compensatory renal growth even in the fetus, a response that could prove maladaptive later in life through excessive glomerular hyperfiltration and progressive interstitial fibrosis.

CONCLUSIONS

These factors underscore the importance of attempting to maximize functional renal mass in the neonate or infant with renal impairment of any etiology.

Short dialyzed children respond less to growth hormone than patients prior to dialysis. German Study Group for Growth Hormone Treatment in Chronic Renal Failure

Recombinant human growth hormone (rhGH) is a new treatment modality for short children with chronic renal failure (CRF) prior to and during dialysis. It is difficult to analyze whether dialysis patients respond less to rhGH than children with CRF on conservative treatment because they are older and often in a pubertal age range. One hundred and eight patients were treated with 28-30 IU rhGH/kg per week for at least 1 year. We analyzed the growth response to rhGH in 56 prepubertal patients aged less than 10 years at the start of rhGH treatment; 38 children with a mean age of 6.5 +/- 2.4 years were on conservative treatment (CT) and 18 patients with a mean age of 6.5 +/- 2 years on dialysis treatment (D). Mean height velocity was 4.9 +/- 2.3 cm/year in children on CT and 4.6 +/- 1.8 cm/year in children on D. During the 1st treatment year, height velocity was 9.5 +/- 3.8 cm/year in CT patients and 7.3 +/- 1.3 cm/year in D patients (P < 0.05). The change in height was +1.1 +/- 0.8 standard deviation (SD) in CT patients and +0.5 +/- 0.4 SD in D patients (P < 0.005). During the 2nd treatment year, the change in height was again greater in CT patients (0.5 +/- 0.4 SD vs. 0.2 +/- 0.4 SD; P < 0.05). The difference in height velocity and change in height standard deviation score was also significant when a subgroup of patients was matched for sex, age, height. Height velocity and the change in height velocity during rhGH treatment were not correlated with residual renal function, the degree of anemia, or metabolic acidosis. We conclude that short children on D respond less to rhGH than short children on CT, indicating a greater insensitivity to rhGH during D treatment.

Postoperative medium-term follow-up of patients with bilateral, massive primary vesicorenal reflux and reduced renal function at presentation

We report the results of a medium-term follow-up study of 52 patients with bilateral, massive primary vesicorenal reflux (PVRR) with renal damage at presentation. Ten infants between 2 and 5 months of age, with a total of 19 renal units, had a temporary vesicostomy followed by ureteral reimplantation after 12-15 months; 42 patients with 81 renal units had primary ureteral reimplantation. The postoperative observation period covered 9.5 years on average (20 months - 21.5 years). The study showed that: (1) urinary specific gravity remained reduced in about 61% of patients; (2) proteinuria improved significantly, in a direct proportion to the favorable evolution of renal function; (3) the frequency of acute pyelonephritis decreased significantly from 98% to 23%. Postoperatively, 27 patients (51%) had one or more episodes of urinary tract infection (UTI) and 12 (23.0%) still had episodes of acute pyelonephritis. (4) At follow-up 7 patients (13.5%) had stable hypertension, while 3 others had unstable hypertension (19.2%); 8 had chronic renal insufficiency or end-stage renal disease. When only adolescents more than 12 years old were considered, the incidence of hypertension increased to 34.4% (10.29). (5) Some renal scarring developed despite successful antireflux surgery, and parenchymal growth, which was severely impaired prior to surgery, restarted although it remained below - 2 standard deviations from the mean. (6) In the overall series glomerular filtration rates (GFR) significantly improved after successful surgery. However, this improvement was much more evident in patients operated upon within the 1st year of life and in those who had had a temporary vesicostomy. In the subgroup of patients operated upon after 6 years of age, successful surgery had no effect on the further decline of renal function when this was already severely compromised. We conclude that early antireflux surgery or, in selected cases, temporary vesicostomy followed by ureteral reimplantation was effective in significantly improving GFR and sharply decreasing febrile UTIs in patients with massive bilateral PVRR and renal damage at presentation.

Early age-dependent growth impairment in chronic renal failure. European Study Group for Nutritional Treatment of Chronic Renal Failure in Childhood

We report early linear growth in 73 children (51 boys, 22 girls) with early onset of chronic renal failure (CRF). The inclusion criteria was onset of CRF before 6 months of age, two or more height measurements during the 1st year of life, follow-up for at least 3 years and continuously impaired renal function with a glomerular filtration rate below 50 ml/min per 1.73 m2 at 1 year or later. Only height measurements taken during conservative treatment or dialysis were included. The data were analysed in terms of the infancy-childhood-puberty growth model. There was an age-dependent growth failure in early life leading to an attained height of -3 standard deviation score (SDS) at 3 years of age. Approximately one-third of the reduction in height occurred during fetal life and one-third during the first postnatal months. Between 0.75 and 1.5 years of age height also decreased by 1 SD as a consequence of a delayed onset of the second, the 'childhood', phase of growth in 36% of the patients and by an 'offset childhood' growth pattern--i.e. a return to the infancy phase pattern after onset of the childhood phase--in 60% of the patients. Growth between 0.25-0.75 and 1.5-5 years of age was generally percentile parallel and thus less likely to be affected in CRF with early disease onset. The glomerular filtration rate was not related to the height gain in early life. We speculate that the growth failure during fetal life and the first postnatal months reflects metabolic and/or nutritional influences and the impaired growth at 0.75-1.5 years of age is related to a partial insensitivity to growth hormone.

Growth charts for prepubertal children with chronic renal failure due to congenital renal disorders. European Study Group for Nutritional Treatment of Chronic Renal Failure in Childhood

Despite the high prevalence of and therapeutic attention to growth failure in children with chronic renal failure (CRF), systematic evaluations of spontaneous growth in CRF are lacking. Therefore, we collected retrospectively longitudinal growth and biochemical data in 321 prepubertal patients treated for CRF due to congenital renal disorders. Data were recorded at 3-month intervals during the first 2 years of life and 6-monthly thereafter, up to the age of 10 years. Around 100 measurements were available per age interval. Mixed-longitudinal percentile curves of height and height velocity were constructed. Moreover, a statistical comparison with the heights and height velocities of healthy children and an evaluation of the effect of biochemical parameters on growth was performed. The CRF children had normal heights at birth but dropped below the 3rd normal percentile during the first 15 months of life. Thereafter, growth patterns usually were percentile parallel, with a mean height standard deviation score (SDS) of -2.37 +/- 1.6. Height velocities were consistently lower in patients with glomerular filtration rates (GFRs) below one-third of the lower normal limit (25 ml/min per 1.73 m2 for patients > 1 year) than in patients with better renal function. This difference in growth rates resulted in a mean height SDS of -1.65 +/- 1.5 SDS and -2.79 +/- 1.4 SDS (age 1-10 years) in the subgroups with relatively better and worse GFR, respectively. Regression analysis confirmed that GFR was a weak but significant predictor of height velocity SDS in most age groups.

Evolution of upper urinary tract and renal function in patients with posterior urethral valves

From January 1972 to June 1993, 166 patients with posterior urethral valves (PUV) were treated in our surgical department, 59 with a milder form of PUV (upper urinary tract [UUT] complication rate 29%) and 107 with a severer form (UUT complication rate 96.3%). Only the latter group was studied for long-term (mean 9.3 years) evaluation of the UUT and renal function. A temporary vesicostomy was the primary treatment in 25 patients. Indications for temporary diversion were very young age and/or low birth weight, severe and bilateral UUT complications, and severe renal damage. All the other patients were treated by primary endoscopic valve fulguration. After removal of the lower urinary tract obstruction, vesicorenal reflux (VRR) resolved spontaneously or was ameliorated in 59.2% of the renal units. Spontaneous normalization or evident amelioration were found at long-term follow-up in nearly 70% of dilated, non-refluxing ureters. Ureteral reimplantation was performed on 41 of the 202 dilated or refluxing ureters (surgical rate 20.3%). The surgical failure rate requiring reoperation was 5% (2/41). The prerequisite for successful reimplantation was a large-capacity, stable, and compliant bladder. Ten nephroureterectomies were carried out for unilateral, massive VRR and renal dysplasia; 1 late nephrectomy was performed for arterial hypertension. The evolution of renal function showed statistically significant overall improvement, which was more evident in patients diagnosed and treated in the 1st month of life (P = 0.000) than in those treated between 1 and 12 months (P = 0.004) or after 1 year of age (P = 0.025). Renal function considerably improved in the vesicostomy group (P = 0.000). Thirteen patients (12.4%) are now either dead (2) or have end-stage renal disease (6) or chronic renal insufficiency evolving toward end-stage renal disease (5); 5 of these 13 were treated by vesicostomy in the first days or months of life, and at presentation the glomerular filtration rate (GFR) was less than 25 ml/min . 1.73 m(2). Determination of basic GFR and, even more, functional renal reserve is relevant in predicting the long-term evolution. In the author's opinion, vesicostomy is the procedure of choice in very ill newborns or infants. Aggressive management with early surgical reconstruction is rarely justified, because frequently UUT complications resolve spontaneously or clearly improve, and their surgical treatment has limited and very precise indications.

Pharmacokinetics of vancomycin in critically ill infants undergoing extracorporeal membrane oxygenation

Extracorporeal membrane oxygenation (ECMO) is a widely used therapy for neonates with respiratory failure. Because of sepsis, many of these infants require antibiotics like vancomycin during ECMO treatment. ECMO transiently alters renal function and increases the circulating blood volume by 75%. Initial vancomycin pharmacokinetics were determined in 12 infants undergoing ECMO to determine an adequate drug administration regimen. Vancomycin dosage was based on current recommendations for weight and gestational age. Pharmacokinetic parameters were determined by fitting the data to a two compartment model. This study yielded a mean steady-state volume of distribution of 1.1 +/- 0.5 (range, 0.6 to 2.1) liters/kg and a mean vancomycin clearance of 0.78 +/- 0.19 (range, 0.49 to 1.07) ml/min/kg. The mean vancomycin half-life was 16.9 +/- 9.5 (range, 8.8 to 42.9) h. Nomogram-calculated creatinine clearance was a significant predictor of vancomycin terminal rate constant and clearance. These data suggest alterations in the pharmacokinetics of vancomycin in infants on ECMO. With the goal of achieving vancomycin concentrations in serum above the MIC for the offending pathogen while using the least amount of the drug necessary, new administration guidelines for term infants without renal impairment undergoing ECMO should be 20 mg of vancomycin per kg at an interval of 24 h. With significant renal impairment, the interval should be extended on the basis of concentrations in serum. In comparison with previously published data, the neonates undergoing ECMO in our study demonstrated a much larger volume of distribution, a lower clearance, and consequently a longer vancomycin half-life.

Compensatory hypertrophy and progressive renal damage in children nephrectomized for Wilms' Tumor

Clinical, biochemical, and sonographic evaluation of the remaining kidney function and size was performed in 34 patients, 12 males and 22 females, ages 2.1-19.6 years, nephrectomized (NP) for Wilms' tumor (WT) at least 2 years before (mean 8.6). All patients had normal blood pressure and serum bicarbonates. Two of them had microhematuria, four proteinuria 4 mg/m2/hr, and 11 microalbuminuria (MA) > 20 mg/24 hr. Only one patient had reduced creatinine clearance and maximum bipolar length (MBL) as well as kidney volume (KV) < 100% of expected. In the other patients, average MBL was 128 +/- 11% (P = 0.0001). MBL, but not KV, was inversely correlated (P = 0.04) to age at NP. KV, but not MBL, was directly correlated (P = 0.009) to MA. Average MA was 48 +/- 94 mg/24 hr and was correlated to the time from NP (P = 0.026). The remaining kidney increases in volume much more than in length. The increase in KV is related to the degree of MA, whereas the increase in MBL is higher in subjects younger at NP. The high prevalence of significant MA, which is in turn related to the time from NP and to the KV, raises some concerns about the long-term renal prognosis of children NP for WT.

Pneumococcal polysaccharide vaccine in children with chronic renal disease: a prospective study of antibody response and duration

We studied the antibody response to pneumococcal serotypes 3 and 14 after pneumococcal polysaccharide vaccine was administered to 41 children with renal disease. One month after vaccination, 76% and 61% of patients achieved at least a twofold titer rise to serotypes 3 and 14, respectively; this finding was comparable to historic control values. One year after vaccination, the majority of patients retained protective antibody levels. Achieving a titer > or = 1.0 microgram/ml IgG at 1 month was highly predictive of retaining a protective antibody level > or = 0.15 microgram/ml at 1 year.

Quantitative analysis of glomeruli lesions in patients with mesangial proliferative glomerulonephritis

By using computer imaging analysis system combined with light microscopy, the glomeruli lesions on biopsy specimens sections were quantitatively analysed. The pathological changes of mesangial proliferative glomerulonephritis (MsPGN) in children were quantitatively evaluated and the correlation between the mesangial matrix area (MA) and some clinical data were also analysed. The results indicated that the levels of various glomerular parameters in MsPGN group were higher than those of normal controls. No correlation was found between MA and 24 h urinary protein excretion, but a negative correlation was revealed between MA and estimated GFR. MA was also correlated with the duration of MsPGN recovery. It was suggested that the quantitative analysis of glomerular parameters by computer is a reproducible methods. The parameter of MA may be used for evaluation of the renal function, determination of the duration of therapy and evaluation of prognosis of MsPGN in children.

Management of the difficult nephrotic patient

Most children with nephrotic syndrome do well, usually with multiple relapses and remissions. Some children require high doses of oral steroids to sustain a remission and develop significant steroid toxicity. These patients frequently can be managed with oral alkylating agents or with cyclosporine. A few nephrotic children to not respond to oral prednisone. The most common biopsy finding in steroid-resistant patients is focal segmental glomerulosclerosis. Many patients with this condition progress to chronic renal failure. Evidence suggests that the outcome is improved with either cyclosporine or with a protocol using pulse intravenous methylprednisolone and oral alkylating agents.

Pubertal growth in children with chronic renal failure on conservative treatment

The pubertal growth spurt was followed for at least 3 years in 5 boys and 6 girls with chronic renal failure on conservative treatment. The peak height velocity averaged 8.6 cm/year (range 5.8-10.1 cm/year) in males and 8.2 cm/year (range 6.4-11.5 cm/year) in females. In none was the pubertal growth spurt below the 3rd percentile for chronological age. At the end of the follow-up period, all patients but 2 had stature within the normal limits of parental target. The relative variation of height averaged - 0.013 standard deviation scores per year. On the whole, the pubertal growth spurt was normal in subjects with chronic renal failure on conservative treatment.

Technetium-99m mercaptoacetyltriglycine clearance: reference values for infants and children

Six hundred and thirty-nine clearance studies performed in children aged 7 days to 19 years utilizing technetium-99m mercaptoacetyltriglycine (MAG 3) were retrospectively analysed. Standardized conditions for the investigation included: parenteral hydration (60 ml/hxm2 body surface) in addition to normal oral fluid intake, weight-related dose of 99mTc-MAG 3 (1 MBq/kg body weight, minimum 15 MBq) and calculation of clearance according to Bubeck et al. Of the 513 children, 169 included in this analysis could be classified as "normal" with regard to their renal function. Normal kidney function was judged by the following criteria: normal GFR for age, normal tubular function (absence of proteinuria and glucosuria), normal renal parenchyma (on ultrasonography, MAG 3 scan and intravenous pyelography), absence of significant obstruction and gross reflux (>grade I), no single kidney and no difference in split renal function >20%. Results showed increasing MAG 3 clearance values for infants during the first months of life, reaching the normal range for older children and adults between 7 and 12 months.

Body growth in children with polycystic kidney disease. Arbeitsgemeinschaft für Pädiatrische Nephrologie

We analysed the body growth of 121 prepubertal children with polycystic kidney disease participating in a longitudinal multicentre study. The patients were followed from an age of 1 to 9 years in girls and 1 to 10 years in boys over a mean period of 3.6 years. Children with end-stage renal disease were excluded. Fifty-four patients had the autosomal dominant form of the disease and 67 the autosomal recessive form. At last observation, 2% of patients with the dominant form and 28% of those with the recessive form had an estimated glomerular filtration rate of < 60 ml/(min 1.73 m2). At first observation, the mean height SD score (SDS) in patients with the dominant form was almost the same as in controls, whilst in those with the recessive form it was significantly decreased (girls -0.82 SDS, boys -0.68 SDS, p < 0.001). During the follow-up the height SDS decreased slightly in both groups (NS). In patients with autosomal recessive kidney disease the degree of growth retardation appeared to be related to renal function: at last observation the height of girls with an estimated glomerular filtration rate of < 60 ml/(min 1.73 m2) was more retarded than that of boys (mean -2.1 SDS versus -1.5 SDS, NS). The height SDS and renal function at last observation correlated in girls (r = 0.83, p < 0.001) but not in boys (r = 0.55) with the recessive form. No correlation was found between the height SDS and hypertension. The weight-for-height SDS at onset was significantly reduced in patients with the recessive form with decreased renal function. Our data suggest that the autosomal recessive, but not the dominant, form of polycystic kidney disease is associated with early growth retardation, which seems to be more severe in girls, probably due to the more rapid deterioration of renal function.

Immune response to influenza vaccination in children with renal disease

Although immunization with influenza vaccine is recommended for children with chronic renal disease and after organ transplantation, the antibody response in these children has not been well described. We studied the response to the 1993-1994 trivalent influenza vaccine in children, aged 1-21 years, with chronic renal failure (n = 15), end-stage renal disease requiring dialysis (n = 10), and post renal transplantation (n = 17). Each group's antibody response was compared with that of a control group (n = 7). No significant differences were found in seroconversion rates, percentage of patients achieving protective hemagglutination-inhibition titers post vaccination or change in geometric mean titers from pre to post vaccination between study groups and controls. These results suggest that pediatric patients with renal disease will respond and therefore will benefit from currently recommended influenza immunization.

Length/serum creatinine ratio does not predict measured creatinine clearance in critically ill children

OBJECTIVE

Information regarding renal function is important in critically ill children to adjust the dosage of drugs that are eliminated by the kidneys. Methods for estimating glomerular filtration rate (GFR) based on age and serum creatinine level have shown good agreement with measured creatinine clearance (CLCR) in children without critical illness but have not been examined in critically ill children.

METHODS

CLCR (24 hours) was measured (CLCR-measured) in 100 individuals (aged 5.6 years [range, 0.1 to 20.8 years]) admitted to a pediatric intensive care unit. Urine was collected by indwelling bladder catheters. Serum levels were determined. CLCR was calculated (CLCR-measured) according to the standard formula. GFR was estimated (CL-estimated) according to a published method, in which GFR is based on serum creatinine levels, patient length, and a constant that varies with the age and sex of the child. For each patient, the percentage difference between methods was calculated as the difference between the methods divided by the average obtained by the two methods and expressed as a percentage. Bias was calculated as the absolute value of the percentage difference.

RESULTS

CLCR-measured and CL-estimated were significantly correlated (CLCR-measured = 0.57 CL-estimated + 16.8; r = 0.68; p < 0.001). However, CL-estimated was greater than CLCR-measured in 84 patients. The difference ranged from -230 to +123 ml/min/1.73 m2 (mean -25.9 ml/min/1.73 m2 [95% confidence interval, -18.1 to 33.7 ml/min/1.73 m2]). The mean percentage difference between the methods was also large (-38.1% [95% confidence interval, -47.1% to 29.2%]) and ranged from -153.2% to 102.1%. The mean bias was 45.2% (95% confidence interval, 37.7% to 52.8%). In 36 of 100 patients the discrepancy between the two methods was greater than 50%. Adjusting for weight percentile, as a proxy for abnormal muscle mass, did not improve the model.

CONCLUSION

A method to estimate GFR in children that is based on age and sex, but not critical illness, does not correspond with measured 24-hour CLCR. Use of this method to adjust dosage of drugs eliminated by the kidney might result in significant overdosage in most critically ill children.

Improved absorption of cyclosporin A from a new microemulsion formulation: implications for dosage and monitoring

Recently, a new oral microemulsion formulation of cyclosporin A (CsA)--Neoral (Sandoz, Basle, Switzerland)--with a higher bioavailability has become available. Ten stable paediatric renal transplant recipients with excessive variations in CsA trough levels with the original Sandimmun (Sandoz, Basle, Switzerland) preparation were switched to Neoral on a 1:1 basis. Pharmacokinetic studies revealed impaired absorption of Sandimmun in six patients. Compared with equal doses of Sandimmun, the 8-h area under the concentration-time curve increased from 1,422 to 2,657 ng x h/ml and the peak concentration rose from 319 to 824 ng/ml (P < 0.01). In six patients with Sandimmun malabsorption, conversion on a 1:1 basis led to a reduction in creatinine clearance which was reversible after dose reduction by 9%-25%. With trough levels at the lower end of the present target range, creatinine clearance stabilised around pre-conversion values.

Quality of life after orthotopic liver transplantation in children. An overview of physical, psychological and social outcome

Orthotopic liver transplantation is now routinely performed as a cure of numerous untreatable paediatric liver diseases. Evaluation of post-transplant quality of life is subjective and very difficult. It has to take into account the pre-transplant quality of life and the emotional stress to the family. Transplantation saves life in 65%-90% of the patients. Several diseases may, however, recur after transplantation, such as hepatitis B, C or NANB, or tumours. Some metabolic diseases may also progress in other organs. Extra-hepatic manifestations or sequelae may persist after transplantation. Complications of transplantation include renal function impairment, hypertension, viral and opportunistic diseases. Of particular concern is the post-transplant lymphoproliferative syndrome. Liver transplantation is able to restore growth. Children are less frequently admitted to hospital after transplantation, take fewer medications, return to school, are less dependent and interact more normally with their peers. Quality of life may not reach perfection, and depends also on the way our society accepts these imperfections.

Gastrocystoplasty: technical and metabolic characteristics of the most versatile childhood bladder augmentation modality

The authors report on 23 patients who underwent complex continent urinary reconstructions, made successful by the selection of gastrocystoplasty as the chosen augmentation modality. The mean patient age was 6.1 years, and the mean weight was 17.9 kg. The minimum follow-up period was 1.5 years. The bladder capacity increased from a preoperative mean of 77.8 +/- 52.2 (SD) mL to a postoperative mean of 303.5 +/- 117.4 mL (P < .000001). No adverse effects on renal function or serum electrolyte composition were encountered, and there were no instances of acidosis or alkalosis. Continence was achieved in 91% of patients. In two patients (0.9%), hematuria-dysuria developed; one case was extremely mild. The other occurred only during a period of severe oliguria and resolved after transplantation. Gastrointestinal complications were minimal. Five patients had end-stage renal disease at the time of reconstruction and have since had successful transplantation. Gastrocystoplasty is particularly applicable to the pediatric population because of its unique anatomic and metabolic characteristics, which bestow tremendous versatility.

Secondary amyloidosis from long-standing bacterial endocarditis

Survival of patients with increasingly complex congenital heart disease has produced a population of children and adolescents who are susceptible to subacute bacterial endocarditis (SBE). We report a child whose endocarditis went unrecognised, and who developed amyloidosis. Asymptomatic proteinuria, haematuria and renal impairment are occasionally seen in SBE and usually indicate glomerulonephritis. Amyloidosis should also be suspected in children with long-standing bacterial endocarditis with proteinuria or other evidence of renal impairment, especially if associated with organomegaly. The diagnosis is made by renal biopsy.

Residual renal function in children on haemodialysis and peritoneal dialysis therapy

Residual renal function was studied in 28 haemodialysis (HD) and 31 peritoneal dialysis (PD) patients aged 1-20 years observed over 6-43 (median 19) months. After the start of dialysis urine volume (UV) decreased to 57%, 46% and 26% of initial mean values in HD patients after 6, 12 and 24 months, respectively. In PD patients the corresponding figures were 57%, 69% and 62%. Mean UV calculated from all individual mean UV measurements observed was higher in PD than HD patients (954 vs. 537 ml/m2 per 24 h, P < 0.01). A better conservation of diuresis in PD patients was also suggested by a significantly longer persistence of a UV greater than 500 ml/m2 per 24 h compared with HD patients. Cox proportional hazard analysis identified dialysis modality and pre-dialysis UV of less than 1,000 ml/m2 per 24 h as the only significant risk factors for UV survival. However, the decline of UV per time was similar in both modes of treatment. No significant changes of glomerular filtration rate were observed during both HD and PD treatment.

Infundibulopelvic stenosis: a long-term followup

We followed 21 patients with congenital infundibulopelvic stenosis, a rare obstructive disorder of the intrarenal collecting system, for a median of 11 years (range 2 to 28 years). Of these patients 19 (90%) had evidence of bilateral renal disease. In particular, 10 patients had bilateral infundibular pelvic stenosis, 6 a contralateral cystic dysplastic kidney and 3 a congenitally absent kidney. Extended observations of the patients with this disorder revealed that end stage renal disease or renal insufficiency developed in 8 patients (37%), all with bilateral renal anomalies. Renal biopsies in patients with end stage renal failure revealed widespread areas of renal dysplasia proximal to the stenotic infundibulum with focal or global glomerulosclerosis of the glomeruli, which was not involved in the dysplastic process. These pathological findings are consistent with the presence of a renal hyperfiltration injury. Our data suggest that the prognosis of infundibulopelvic stenosis is dependent upon the extent of total renal mass involved with the disease process and the duration of followup.

Belgrade and Hantaan hantaviruses--the causative agents of severe haemorrhagic fever with renal syndrome in children in Serbia

During an outbreak of haemorrhagic fever with renal syndrome (HFRS) in 1989, five children (3 girls, 2 boys, aged 6.8-16 years) with a severe form of the disease were treated; four of these were followed for 22-28 months. The main clinical features in all five patients were: fever, headache, myalgia, abdominal and back pain and vomiting; haemorrhagic syndrome was present in four children. Renal syndrome presented with severe acute renal failure in all five patients. All patients recovered. Serological confirmation by an indirect immunofluorescence assay, by enzyme immunoassay for IgM antibodies and by plaque reduction neutralization test showed infection by Belgrade virus in three and by Hantaan virus in two patients. It was not possible to differentiate these two serogroups on the basis of clinical features. This study provides further information on the circulation of different hantaviruses causing severe HFRS in Serbia.

Inaccuracy of glomerular filtration rate estimation from height/plasma creatinine ratio

Use of a height/plasma creatinine formula to estimate glomerular filtration rate (GFR) is simpler and less invasive than renal or plasma clearance methods. The aim of this study was to determine whether these formulas enabled accurate prediction of GFR measured from the plasma clearance of 51Cr labelled ethylenediaminetetra-acetic acid (51Cr-EDTA). Thirty nine patients underwent GFR measurement at least six months after potentially nephrotoxic chemotherapy. Altman-Bland analysis was performed on the measured GFR and that estimated simultaneously using the original and a modified Counahan-Barratt formula and the Schwartz formula. The limits of agreement of the estimated GFR with the measured GFR were unacceptably wide in each case, despite highly significant correlation coefficients. The bias was smallest for the modified Counahan-Barratt formula. Use of these formulas to estimate GFR in children is insufficiently accurate for research purposes and has limitations in clinical practice. Furthermore, use of correlation coefficients to evaluate different methods of measuring GFR is inappropriate.

Body electrolytes in bronchopulmonary dysplasia and the effects of diuretic therapy

Body electrolytes and their regulatory hormones were studied in preterm infants who suffered from bronchopulmonary dysplasia under two groups: those who were not treated with diuretics (Group II), and those who were treated with diuretics (Group III). The values were compared with a group of matched healthy controls (Group I). Lower serum Na levels, a need of higher Na intake, and higher urinary Na concentrations and urinary specific gravity were found in Group II infants. FeNa was normal and the urinary flow rate was lower than the controls. These data suggest an inability of these infants to dilute urine. Group III infants who were treated with diuretics showed higher serum Na levels and lower urinary specific gravity than Group II infants. These values, as well as water and Na intake/output ratios, were all similar to the control values. Serum aldosterone level was highest in Group II but did not reach significance. Intracellular K concentration was not different between the groups indicating an optimum total body K balance. A significant negative correlation between serum Na and aldosterone levels was found in Group II infants, which was not noted in the controls. Significant correlations were also found between FeNa and plasma aldosterone level in the BPD groups, unlike the controls. The control group of infants showed significant positive correlation between Na balance and serum Na levels. Our results suggest that inability to dilute urine appropriately might be the reason for the BPD patients to retain body water. Water restriction and diuretic therapy therefore are reasonable therapeutic approaches in such cases.

Estimation of ifosfamide/cisplatinum-induced renal toxicity by urinary protein analysis

Ifosfamide (IFO) chemotherapy has been reported to result in deToni-Debré-Fanconi syndrome in a minority of patients only, but evaluation of tubular transport capacities has identified a substantial number of patients as having subclinical tubular dysfunction. After completion of combination chemotherapy employing IFO (n = 37) or IFO plus cisplatinum (CPL) (n = 27), glomerular and tubular function was assessed in 64 patients by the urinary excretion of transferrin, IgG, albumin, alpha 1-microglobulin (A1M) and N-acetyl-beta-D-glucosaminidase. Sodium dodecyl sulphate polyacrylamide gel electrophoresis was performed in 21 patients. The determination of urinary marker proteins was compared with the glomerular filtration rate, the fractional phosphate and percent amino acid reabsorption. A reduced glomerular filtration rate was observed in 9.8% of patients. Tubular dysfunction was frequent, with a predominance of renal amino acid (57%) and A1M (48%) loss. IFO-mediated renal toxicity was dose dependent. CPL treatment resulted in significant enhancement of tubular toxicity induced by IFO, whereas concomitant gentamicin therapy did not affect tubular function. Measurement of urinary protein cannot replace other tests for tubular dysfunction in IFO-treated patients, because the spectrum of IFO-induced nephrotoxicity includes dysfunction of different and independent transport mechanisms of the proximal tubular system. Increased urinary A1M excretion is an important indicator of impaired tubular protein reabsorption.

Renal scarring after acute pyelonephritis

Seventy six children, 18 boys and 58 girls, aged 0-15.9 (median 1.0) years, with acute pyelonephritis were prospectively studied with a technetium-99m dimercaptosuccinic acid (DMSA) scan during infection and two months later. Fifty nine of these children were also studied two years after the infection. Seventeen children with a normal DMSA scan during infection or at two months after infection, or both, were not investigated by a DMSA scan at two years after acute pyelonephritis. A micturition cystourethrogram was performed in all the children after two months. Changes on the DMSA scan were found in 65 (86%) children during acute pyelonephritis, in 45 (59%) children at two months, and in 28 (37%) children at two years after infection. Vesicoureteric reflux (VUR) was found in 19 (25%) children at two months. Renal scarring was significantly correlated with the presence of gross VUR and recurrent pyelonephritis, but 62% of the scarred kidneys were drained by non-refluxing ureters. Children with scars were older at the time of acute pyelonephritis than those without scars but no difference was found between the groups with regard to duration of illness, levels of C reactive protein and maximum white cell count, glomerular filtration rate, nor renal concentration capacity at the time of infection. It is concluded that renal scarring after acute pyelonephritis in children is more common than has been previously thought. Although children with gross VUR and recurrent pyelonephritis are at the greatest risk, renal scarring is more often seen without these risk factors.

Prognostic value of sonography in childhood nephrotic syndrome

This retrospective case review of 43 children with primary nephrotic syndrome was designed to evaluate the relationship among renal ultrasound findings at presentation, subsequent corticosteroid responsiveness and histological diagnoses. Fifty-one percent of patients had abnormal sonograms; nephromegaly was present in 42% and increased renal echogenicity in 35%. There was no relationship between nephromegaly and either response to corticosteroids or specific glomerular lesions causing nephrosis. Although the presence of echogenic kidneys did not denote a particular type of renal disease, it was significantly more frequent in corticosteroid-resistant than in corticosteroid-responsive patients (62% vs. 18%, P < 0.05). We conclude that increased renal echogenicity at time of presentation is a possible indicator of corticosteroid resistance in children with primary nephrotic syndrome.

Ifosfamide-induced subclinical nephrotoxicity and its potentiation by cisplatinum

Renal function was assessed in 72 children and adolescents 3.5 to 123 months after completion of chemotherapy employing ifosfamide (n = 39) or ifosfamide plus cisplatinum (n = 33). No patient had preexisting renal parenchymal disease. Whereas reduction in glomerular filtration rate was present in six of 69 patients (8.7%), impairment of tubular transport for phosphate, glucose, and amino acids was more frequent: 32.8% of the patients showed reduction in phosphate reabsorption, and glucose and amino acid reabsorption was lowered in 16.4% and 55.0%, respectively. Elevated sodium excretion was found only occasionally, and there was no evidence of renal tubular acidosis. Proximal tubular damage is related to ifosfamide chemotherapy, but correlation between ifosfamide dose and phosphate reabsorption was not linear. The most severe depletion of phosphate reabsorption was seen in patients treated with both ifosfamide and cisplatinum. On reexamination of phosphate reabsorption after a median interval of 8 months, the majority of patients with initially reduced values showed further deterioration of this function.

Aluminum in the neonate related to parenteral nutrition

Sources of aluminium loading and exposure in preterm and full-term newborns were studied. Parenteral nutrition solutions were the main source of aluminium representing 88.7% of total aluminium intake. Blood and urine aluminium levels were followed over a 28-day period in a group of 26 preterm and 9 term infants while receiving parenteral nutrition (duration 15.6 +/- 8.7 days) and later when being formula fed. Urine levels were followed up to 13 weeks in a subgroup of the neonates. Serum aluminium levels (0.86 +/- 0.38 mumol/l) and urine aluminium/creatinine ratio (1.52 +/- 0.81 mumol/mmol) were increased when the infants were receiving parenteral nutrition compared with the control group (p < 0.001). The urine aluminium/creatinine ratio remained high up to 10 weeks following withdrawal of parenteral nutrition and suggested tissular loading. This was confirmed after high aluminium levels were found in post-mortem brain and bone samples from two preterm and one full-term infant. We conclude that both preterm and full-term neonates are susceptible to accumulation of aluminium in tissue while receiving parenteral nutrition.

The renal clearance and infusion clearance of inulin are similar, but not identical

Thirty-eight simultaneous renal (R-Cin) and infusion (INF-Cin) clearances of inulin were done. The equilibration period preceding the clearance studies was of at least two hours duration. The R-Cin on each subject was based on two clearance periods during which the plasma inulin concentration ([P(in)]) varied by 1.0 mg/dl or less and the rate of inulin excretion by less than 10%. There was excellent correlation between the R-Cin and the INF-Cin (r = 0.976), but the INF-Cin consistently exceeded the R-Cin (mean difference = 13.8 +/- 8.8 ml/min/1.73 m2, t = 9.7163 and P = < 0.001). Complete equilibration of inulin in body fluids has been assumed when [P(in)] levels were relatively constant (variation < 10%). However, complete equilibration of inulin would not be present, even with relatively constant P(in) levels, if the rate of infusion of inulin were equal to the rate of excretion plus the rate of penetration of inulin into less permeable components of the extracellular fluid compartment (that is, dense connective tissue solids). Estimation of glomerular filtration rate using the INF-Cin requires complete equilibration of inulin in body fluids, a process probably requiring 12 to 15 hours or longer.

Treatment of IgA nephropathy in children: efficacy of alternate-day oral prednisone

We have previously reported our experience with the use of alternate-day prednisone in the treatment of 6 patients with IgA nephropathy who have clinical or pathological risk factors for disease progression. We have now treated a total of 13 patients and followed them from 4 to 10 years. Patients received an alternate-morning dose of prednisone for 2-4 years. Dosage began at 60 mg/m2 for 3 month, was reduced to 30 mg/m2 by 1 year and 15 mg/m2 by 2 years. At last observation, urinary protein excretion was normal in 12 patients and no patient had hematuria. Twelve patients had normal estimated glomerular filtration rate (GFR) and one had renal insufficiency (GFR = 38 ml/min per 1.73 m2). A renal biopsy was performed in 11 patients after 2 years of treatment. Activity score decreased from 5.2 to 4.3 (P = 0.03) and chronicity score increased from 2.2 to 2.8 (P = 0.12). There were no complications of treatment. When compared with a historical group, the treated patients had a significant improvement in urinalysis (P < 0.00001) and preservation of normal GFR (P = 0.03). We conclude that alternate-day prednisone therapy may benefit patients with IgA nephropathy. A large prospective controlled trial is needed.

Impact of tuberculosis in children with idiopathic nephrotic syndrome

Forty black South African children (mean age 4.7 +/- 2.6 years) with idiopathic nephrotic syndrome due to focal glomerulosclerosis (FSGS) were evaluated. Tuberculosis (TB) was found in 37.5% of children with FSGS (FSGS-TB) compared with 6% of a comparable group with minimal lesion nephrotic syndrome. No significant differences were found in the initial mean serum albumin, cholesterol, triglyceride and creatinine levels in FSGS-TB compared with children with glomerulosclerosis but without TB (FSGS-nonTB). The mean serum levels of C4, IgA and IgM were increased by 30%, 25% and 23%, respectively in children with FSGS-TB compared with FSGS-nonTB. Initial estimated creatinine clearance was similar in the two groups, but after a mean follow-up of 2.4 years, the mean estimated creatinine clearance of children with FSGS-TB was significantly reduced by 46% from the initial value, but remained stable in the FSGS-nonTB group. FSGS-TB children also had significantly increased requirements for renal replacement therapy compared with children with FSGS-nonTB. We conclude that TB infection is commonly associated with FSGS in black South African children; this may have deleterious effects on renal function.

Respiratory function in the prune-belly syndrome

Respiratory function was evaluated in 11 patients with prune-belly syndrome. Nine had evidence of gas trapping and six of restrictive lung disease. These abnormalities of lung function appear to be secondary to the musculoskeletal disorder associated with prune-belly syndrome rather than parenchymal lung disease.

Protein restriction in chronic renal failure

The aim of the study was to investigate the effect of a protein restricted diet on renal function and growth of children with chronic renal failure. In a multicentre prospective study 56 children (aged 2-18 years) with chronic renal failure were randomly assigned to the protein restricted (0.8-1.1 g/kg/day) or the control group. All children were followed up by the same paediatrician and dietitian. After a follow up period of three years there was no significant difference in glomerular filtration rate between children on a protein restricted diet and children of the control group. There was no significant difference in weight with respect to height and height SD score between the protein restricted and the control group. Compliance with the protein restricted diet, as indicated by the prospective diet diaries and the serum urea:creatinine ratio, was good. This study shows that children with chronic renal failure do not benefit from a protein restricted diet.