Stanley Hellerstein

Growth and development of infants with end-stage renal disease receiving long-term peritoneal dialysis*

The growth and development of four infants with end-stage renal disease receiving long-term peritoneal dialysis was studied during the first year of life. In each patient, dialysis was begun before 4 weeks of age. A nutritional regimen was designed to attain a daily weight gain appropriate for height age while minimizing the blood urea nitrogen level. A neurodevelopmental evaluation of gross and fine motor, cognitive, language, and psychosocial skills was performed at least every 3 months. At age 1 year, the mean height standard deviation score (SDS) was -1.33 +/- 0.2. Weight for height was greater than 95th percentile in one patient and normal in three. Mean caloric and protein intake were 105 +/- 20 kcal/kg/d (11.4 +/- 2.7 kcal/cm/d) and 2.7 g/kg/d (0.30 +/- 0.11 g/cm/d), respectively. Mean blood urea nitrogen was 53.6 +/- 17.8 mg/dL. Developmentally, three of the patients were functioning in the normal range and one was mildly retarded. However, gross motor skills were delayed in all patients. Although infants with end-stage renal disease are usually severely growth retarded and developmentally delayed, our observations suggest that early nutritional intervention and dialysis can yield improved results.

Nutritional management of children with chronic renal failure. Summary of the task force on nutritional management of children with chronic renal failure.

Current information on the adaptations to progressive loss of renal function is presented. The assessment of renal function in infants and children using serum creatinine concentration and its derivatives is considered as are various methods for assessment of growth. Children with creatinine clearances less than 50% of normal, who do not have uremic symptoms (and who are not on dialysis), should be ingesting diets providing close to 100% of the RDA for calories with 8% of the calories as protein. Recommendations for nutritional management of children on chronic peritoneal dialysis are also presented.

Recombinant human erythropoietin therapy in pediatric patients receiving long-term peritoneal dialysis

We evaluated the impact of (s.c.) recombinant human erythropoietin (r-HuEPO) therapy on the hematological status, exercise capacity, and dietary intake of nine pediatric patients (mean age 12.4±3.2 years) receiving long-term peritoneal dialysis. Five children without medical illness served as controls for the exercise testing portion of the study. Following 7.9±2.8 weeks of twice weekly r-HuEPO (50 units/kg per dose), the hematocrit increased from 21.9±3.5% to 31.3±2.5% (P<0.001). A further increase to 33.2±3.0% occurred after 2 months of once weekly therapy. The blood transfusion requirement decreased from 0.5 transfusions per patient-month to 0.05 transfusions per patient-month (P<0.01). Graded exercise testing demonstrated an increase in peak oxygen consumption from 17.8±5.2 to 24.0±7.6 ml/kg per min (P<0.01). The oxygen consumption at anaerobic threshold increased from 13.1±3.9 to 17.1±3.5 ml/kg per min (P<0.02). Treadmill time increased from 5.3±1.2 to 7.5±1.3 min (P<0.001). In each case, the percentage improvement was significantly greater than the improvement seen in the control population. Dietary evaluation revealed no significant change in caloric or protein intake, despite a subjectively improved appetite. r-HuEPO, given by the s.c. route, corrects the anemia and improves the exercise capacity of pediatric patients receiving long-term peritoneal dialysis.

Validation of creatinine assays utilizing HPLC and IDMS traceable standards in sera of children

The purpose of this study was to validate serum creatinine (SCr) concentrations assayed in the Central Biochemistry Laboratory of the National Institutes of Health (NIH)-funded Chronic Kidney Disease in Children (CKiD) study utilizing an enzymatic assay (Siemens Advia 2400) against a method traceable to reference isotope dilution mass spectroscopy (IDMS) developed by the National Institute of Standards and Technology (NIST). High-performance liquid chromatography (HPLC) measured SCr after external validation utilizing IDMS-based standard reference materials. Sera from the first 201 subjects enrolled in CKiD were analyzed and compared for creatinine concentration by enzymatic and HPLC methods. Fifty “normal” pediatric sera were subsequently analyzed. Finally, a “pediatric” reference standard was prepared and examined for accuracy and precision. Enzymatic SCr concentrations (median 1.4xa0mg/dl) of CKiD subjects were well correlated with HPLC (ru2009=u20090.984) but were slightly higher (+7%; pu2009<u20090.001). Agreement was poorer at lower SCr (median 0.4xa0mg/dl) when using samples from normal children and the “pediatric” reference standard. However, the Roche enzymatic assay was comparable with HPLC in accuracy and precision. Referring physicians should be aware of the accuracy and reproducibility of their laboratory’s SCr assay. Our enzymatic assay agreed well with HPLC in CKiD subjects with elevated SCr. We suggest that NIST develop a pediatric SCr standard reference material for use by assay manufacturers to improve accuracy and precision of assays at the low SCr levels observed in most pediatric patients.

Autosomal dominant inheritance of multicystic dysplastic kidney

Abstractu2002Unilateral multicystic dysplastic kidney (MCDK) in a normal infant is believed to be a sporadic disorder, with an incidence of about 1 in 4,300 live births. Isolated unilateral MCDK occurring in a family without other genitourinary abnormalities has not been described. We report a family in which isolated unilateral MCDK occurred in a woman and her two children. The mother presented with a palpable abdominal mass during infancy, which on excision was found to be a MCDK. Both the children were found to have MCDK on prenatal ultrasonography, which was later confirmed on postnatal evaluation. The MCDK in the children continues to involute on follow-up urinary tract ultrasonography. The inheritance of MCDK appears to be autosomal dominant in this family.

Vitamin status of infants receiving long-term peritoneal dialysis

The oral vitamin intakes and blood vitamin concentrations of seven infants receiving long-term peritoneal dialysis were measured. The serum concentrations of vitamin A, vitamin B12, vitamin C and folic acid were determined. Thiamine and riboflavin were assessed by the activation of erythrocyte transketolase and erythrocyte glutathione reductase, respectively. Vitamin B6 was measured as plasma pyridoxal phosphate. All patients received a daily vitamin supplement devoid of vitamin A. Dietary vitamin intake was derived from infant formula. In all cases, the patients blood concentrations of the water-soluble vitamins were equal to or greater than normal infant values. Serum vitamin A levels were elevated despite the lack of supplementation. The combined dietary/supplemental water-soluble vitamin intake of the patients exceeded the recommended daily allowance in all but one patient. These preliminary data emphasize the need to further evaluate the vitamin requirements of infants receiving long-term peritoneal dialysis.

The cimetidine protocol: a convenient, accurate, and inexpensive way to measure glomerular filtration rate

1.73 m2 (measured or calculated) to a maximum of 1,600 mg. The dose is reduced to 80% for those with CCr 50–75 ml/min per 1.73 m 2 , to 70% for CCr 30–50 ml/min per 1.73 m2, to 60% for a C Cr of 20–30 ml/min per 1.73 m 2 , and to 50% for those with a CCr <20 ml/min per 1.73 m 2 . A final dose, of half the daily dose, is given approximately 2 h before beginning the urine collection on the morning of the day of the clearance study.

Timed-urine collections for renal clearance studies

The purpose of this study was to describe the reproducibility of timed-urine collections for renal clearance studies and the effect variations in urine collection has on measurement of glomerular filtration rate (GFR). Data from 222 cimetidine clearance studies (GFR-Cim) were obtained from 32 pediatric renal patients over a period of 8 years. There were three to 18 studies per child aged 4.8 years to 21 years at the time of a study. The urinary creatinine excretion rate is measured during supervised urine collection periods. The creatinine excretion rates in each child were compared to obtain data on the reproducibility of the urine collections. The coefficient of variation (CV) of the creatinine excretion rate is approximately 10% in both children and adults. The variation in GFR to be expected during repeated renal clearance studies in subjects with stable GFR, using voided urine collections, was similar in children and adults, with a CV of 12% to 14%.

Creatinine excretion rates for evaluation of kidney function in children

A protein load protocol for evaluation of kidney function was tested in normal children and pediatric renal patients. An overnight, timed urine collection was used for calculation of the baseline cretinine clearance and creatinine excretion rate. One hour following ingestion of a standardized protein meal (baked chicken), a 2–3 h urine collection was begun. The post-protein meal changes in creatinine clearance showed considerable variation in both the normal children and those with renal disorders. In contrast, the rate of excretion of creatinine was consistently increased in the normal children following the protein meal (73.4±18%; range 48.2%–122.4%). Of 33 renal patients, 14 showed less than a 48% increase in creatinine excretion rate, even though 9 of these children had baseline creatinine clearances within the normal range. These 9 patients have evidence of less than normal quantities of functioning renal tissue. Serial studies over a year on 2 children who presented with acute renal failure showed a progressive increase in creatinine clearance with scant increases in creatinine excretion rate. These studies provide indirect evidence that a less than normal enhancement of the rate of creatinine excretion following a protein load reflects the presence of adaptive glomerular hyperfiltration and hyperperfusion.

Septicemia and subperiosteal cephalhematomas

Summary The clinical courses of 2 infants with recurrent septicemia and meningitis have been described. The condition of the infants deteriorated while they were receiving antibiotics to which the infecting organisms were sensitive. Blood cultures became positive and the patients developed purulent meningitis. Infected cephalhematomas were apparently the foci of these persistent infections. Diagnostic aspiration of subperiosteal cephalhematomas should be considered in the management of infants with clinical septicemia or meningitis.