Donald I. Moel

FAMILY ADJUSTMENT TO PEDIATRIC AMBULATORY DIALYSIS

Continuous ambulatory peritoneal dialysis has recently been a successful medical treatment for children with end-stage renal disease. The psychosocial issues for families and patients are considered within the context of the childs developmental stage (infants and toddlers, school age, and adolescence). The parents conflicting duties as both a provider of medical care and a parent often lead to disturbances in family relationships.

Renal function 9 to 17 years after childhood lead poisoning.

Renal function was studied in 74 subjects who, between 1966 and 1972 (ages 1 to 6 years) had had blood lead levels (PbB) ≥100 μg/dl (range 100 to 471 μg/dl, median 142 μg/dl) and in 21 sibling controls. PbB measured in 1983 in study subjects remained significantly higher than in sibling controls (mean ± 1 SD 14.5 ± 4.5 vs 11.6 ± 2.6 μg/dl, P 2 -microglobulin (β 2 -M), and elevated fractional excretion β 2 -M %×100 was similar in the two groups. Mean values for these tests were similar in study subjects compared with sibling controls. Mean systolic blood pressure was significantly higher in study subjects compared with that in sibling controls (117±12 vs 109±10 mm Hg), but the control group contained a preponderance of females and the study group had more overweight females; mean diastolic blood pressure was similar in the two groups. We conclude that in our adolescent subjects who had had lead poisoning 9 to 17 years earlier, there is little if any evidence of chronic nephropathy.

Successful renal transplantation in a 3-month-old infant

as in our first patient. Such a well-defined purely echolucent mass probably represents a central hematoma of the adrenal gland. Our pat ient 2 had a Complex mass with both cystic and solid elements; this pattern is consistent with adrenal hemorrhage and adrenal necrosis, a combination found in 15% of hemorrhagic adrenal glands at autopsy, 3 but it could also represent adrenal hemorrhage with clot. The possibility that neonatal neuroblastoma could cause these ultrasonic findings underlines the necessity for obtaining careful f011ow-up in such patients, although in neonatal neuroblastoma the solid elements predominate over the cystic. In addition, the clinical history, rapid resolution of the mass, and lack of any symptoms or signs of neuroblastoma made this diagnosis unlikely in Patient 2. The value of ultrasonography is emphasized because it is safe, simple, and noninvasive. Fol low-up studies with abdominal ultrasound provide an easy method to follow the resolution of adrenal hematomas.

The Role of Prostaglandins in Early Polyuria Induced by Cisplatin in the Rat

To assess a possible role of prostaglandins in the early phase of cisplatin-induced abnormalities in renal concentrating ability, three groups of rats were studied. In a first group we measured prostaglandin production from renal medullary microsomes isolated from rats sacrificed at different time periods after cisplatin, 5 mg/kg alone (PB/CP) or cisplatin plus aspirin, 300 mg/kg p.o., 1 h before cisplatin and daily (ASA/CP). In a second group of rats, balance studies were performed in PB/CP and ASA/CP animals for 4 days after cisplatin to determine the effect of such treatment on the renal excretion of solute and water. In another group of rats inulin clearance was measured in PB/CP and ASA/CP animals 4 days after such treatment. The rats received aspirin or phosphate buffer alone (50 mg/ml sodium phosphate, pH 8) to determine the effect of such treatment on prostaglandin production and renal function. In PB/CP Uosm fell and prostaglandin synthesis increased on days 1-3. Prostaglandin synthesis returned to baseline values by day 4, but Uosm remained low. Inulin clearance was low 4 days after cisplatin. In ASA/CP rats prostaglandin synthesis did not increase and the early polyuria was ameliorated. Aspirin did not prevent the later polyuria. Inulin clearance in the ASA/CP group was markedly reduced to levels below those observed with cisplatin alone. These data demonstrate that elevated rates of prostaglandin synthesis occur early in the course of cisplatin-induced renal failure and suggest that prostaglandins may play a role in the early cisplatin-induced concentrating defect.

Continuous Ambulatory Peritoneal Dialysis: The Pediatric Experience

Continuous ambulatory peritoneal dialysis has become a highly acclaimed method of maintenance therapy in the management of end stage renal disease in childhood. This type of dialysis affords freedom and comfort, and lessens dependence. Furthermore, the over-all reduction in hospital-related cost of this therapy currently has made continuous ambulatory peritoneal dialysis the recommended procedure of choice at our institution. From July 1980 through May 1986 we offered this form of therapy to 45 patients between 4 days and 17 years old. A total of 68 Tenckhoff catheters were placed. Reasons for catheter removal included persistent peritonitis, tunnel infection, catheter leakage, catheter obstruction, successful kidney transplant, motivational failure, midline nephrectomy and death. Patient and parent instruction and indoctrination were critical factors in catheter survival. Our experience with the specific technical aspects of insertion documented that the single cuff, coiled Tenckhoff catheter and long, subcutaneous tunnel were definite advantages. These factors favored early use and long-term survival. The course of these patients with respect to nutrition, growth, emotional activity, infections and catheter survival is presented.

Renal prostaglandin E2 synthesis and degradation in the developing rat.

Postnatal development of glomerular filtration rate (GFR) and renal blood flow is associated with a fall in renal vascular resistance that may be mediated by vasoactive substances. We examined differences in the regulation of one such substance, prostaglandin E2 (PGE2). The present studies examined renal cortical and medullary PGE2 synthesis and degradation in rats aged 20 days (30.7 g), 31 days (101 g), and 120 days (413 g). PGE2 synthesis in cortical microsomes was highest in 20-day-old rats compared to 31- and 120-day-old rats. In contrast, medullary PGE2 synthesis was lowest in 20-day-old rats compared to 31- and 120-day-old rats. Both cortical and medullary PGE2 degradation were highest in 20-day-old rats and decreased with age. Despite demonstrating significant age-dependent differences in cortical and medullary PGE2 synthesis, 11 days of aspirin given between age 20-31 days blocked PGE2 synthesis in cortex and medulla by 60 and 76%, respectively, but GFR was similar to control 31-day-old rats (0.78 +/- 0.04 ml/min/g kidney weight, aspirin-treated, versus 0.85 +/- 0.03 ml/min/g kidney weight, control), suggesting that observed age-dependent differences in renal PGE2 synthesis is not a major determinant of development of GFR. A more important determinant of GFR may be age- related differences in renal cortical prostaglandin turnover.

Pediatric and adult renal transplants: A comparative study

In order to compare the results of renal transplantation in pediatric and adult recipients, a retrospective analysis of first transplants done at a single institution over a 6-yr period was carried out. The study included 21 pediatric and 196 adult recipients of cadaveric grafts, and 18 pediatric and 156 adult recipients of living related grafts. Pediatric and adult recipient groups were shown to be similar to each other with respect to donor-recipient HLA antigen matching and to causes of graft failure and patient mortality. Actuarial graft and patient survival data for pediatric recipients was found to be better than for the corresponding adult recipient groups, although the differences were not statistically significant. When clinical results, technical problems, and psychosocial adaptation are considered critically, transplantation is clearly preferable to both hemodialysis and to no treatment for pediatric patients with end stage renal disease (ESRD). There is a considerable discrepancy between the estimated incidence of ESRD in children and the number of children being tranplanted for this disease. Many patients are, therefore, receiving less than optimum treatment. Efforts to correct this discrepancy are in order.

1836 FREE WATER CLEARANCE DURING STATUS ASTOBTICUS (SA)

Patients in SA often have elevated plasma antidiuretic hormone levels. To determine if children in SA have impaired water excretion and increased risk of developing hyponatremia when given a fluid challenge (FC), 5 consecutive patients with moderate asthmatic symptoms after 2 doses of epinephrine were given 20 ml/kg of D5 0.2% N.S. i.v. over 30 minutes. Urine was collected at 20 minite intervals for free water clearance (CH2O). This protocol was repeated 24-48 hours later after clinical improvement (CI). Values of serum Na (SNa, mEq/L), serum osmolality (Sosm, mOsm/kg H2O), minimal urine osmolality (min Uosm, mOsm/kg H2O), and CH2O (ml/min) after acute FC in patients during SA and after CI; ()= change in SNa or Sosm after FC. *p<.05, SA vs CI for paired data.There was no difference in SNa or Sosm after FC during Sa vs after CI; 4/5 patients in SA had lower SNa and Sosm after FC and 4/5 after CI had higher SNA and Sosm after FC. Minimal Uosm achieved after FC tended to be lower after CI but the differences were not significant. However, CH2O was significantly lower during Sa vs CI. Despite the small risk of hyponatremia, pediatricians infusing hypotonic fluids to children in Sa should be aware of temporary impaired water excretion.

SEVERE HYPONATREMIA IN INFANTS TREATED WITH CONTINUOUS AMBULATORY PERITONEAL DIALYSIS |[lpar]|CAPD|[rpar]|

With improvements in technology, successful treatment of endstage renal disease in infants by CAPD is possible. After achieving optimal dialysis and reversal of uremia, four consecutive infants developed severe hyponatremia (Na<120 mEq/L) during their first month on CAPD. All 4 infants were males, 7-14 months old, weighing 4.5 - 7.8 kg. Two had obstructive uropathy as the underlying renal disease and one each had polycystic kidney disease and hemolytic uremic syndrome. A typical daily balance study follows:Salt balance was easily maintained with oral salt tablets; blood pressure values did not change significantly with salt supplementation. We conclude that due to dialysate Na losses and infant formulas that may be low in sodium concentration, infants on CAPD may require salt supplements, especially during intercurrent illnesses when oral intake may be limited; these infants are at great risk of developing severe life-threatening hyponatremia. Older children and adults who have free access to dietary salt maintain salt balance with greater ease.

RENAL PROSTAGLANDIN E2 SYNTHESIS |[lpar]|PG SYN|[rpar]| AND DEGRADATION |[lpar]|PG DEG|[rpar]| IN THE DEVELOPING RAT

Postnatal development of GFR and RBF is associated with a fall in renal vascular resistance that may be mediated by vasoactive substances. We examined differences in the regulation of one such substance, PGE2. The present studies examined renal cortical (C) and medullary (M) PG syn and PG deg in neonatal rats (N) aged 17 days (30.7g), young rats (Y) 33 days (101g), and adult rats (A) 120 days (413g). PGE2 syn from 14C-arachidonic acid was determined in C and M microsomes by thin layer chromatography (TLC). PGE2 degradation was determined by following the disappearance of 3H-PGE2 substrate in cytosolic fractions of C and M by TLC. Mean values (±1SE) for PG syn (% arachidonate conversion)and PG deg (% PGE2 disappearance) are shown below: * = p<0.05, N vs Y; † = p<0.05, Y vs A; ψ = p<0.05, A vs N; (n) = number of animals.PG syn in C microsomes is highest in N rats and decreases with age; in contrast M PG syn is lowest in N rats and increases with age. Both C and M PG deg are highest in N rats and decrease with age. These studies demonstrate for the first time that significant age dependent differences in regional PG syn and deg exist in the developing rat kidney. The elevated synthesis of vasodilating PGs in the cortex may play a causal role in the increases in renal perfusion and glomerular filtration typical of the developing kidney.