Ellen G. Wood

Pretreatment of formula with sodium polystyrene sulfonate to reduce dietary potassium intake

Sodium polystyrene sulfonate (SPSS) is commonly administered for the acute and chronic treatment of hyperkalemia. Its oral intake is complicated by poor compliance due to multifaceted reasons. We therefore analyzed a method of reducing potassium (K) in formula by pretreatment with SPSS. If effective, this would bypass complications of enterally administered SPSS and provide low-K formula. Thirteen formulas and nutritional supplements were pretreated with SPSS to determine if one could bind K and provide formulas with decreased K contents. Using an SPSS concentration of 1 g/l mEq K in the formula, 62±2.6% (P<0.01, mean±SEM) of the K was removed in 30 min, while the sodium (Na) concentration was increased by 234±37% (P<0.01). Analysis suggests that the disproportionate increase in Na is due to exchange for calcium (Ca) and magnesium (Mg), interaction with proteins, and Na suspended with SPSS in the formula. Thus, SPSS pretreatment of formula is an effective method of making low-K formula, but the increase in Na exceeds the K reduction. Attention to possible complications of increased Na intake as well as decreased Ca and Mg intake is warranted.

Renal structural-functional relationships in early diabetes mellitus

Abstract.  To define the earliest renal morphological changes in patients with type I diabetes, we studied renal function and morphometric analysis of renal biopsies in 59 patients with diabetes for 5 – 12 years and normal blood pressure, normal creatinine clearance (CCr), and negative dipstick urinary protein. Arteriolar hyalinization and intimal fibrous thickening were noted in 43%. Glomerular basement membrane thickness and fractional mesangial volume were increased in 51% and 56%, respectively. The pre-pubertal and post-pubertal years of diabetes were associated with similar degrees of renal structural changes, but during the pre-pubertal years normal urinary albumin excretion (UAE) was seen. Principal factor analysis of morphometric structural parameters yielded four clusters of variables: “glomerular size” correlated with patient age, CCr, and UAE; “peripheral capillary decrease” correlated with glycosylated hemoglobin, diastolic blood pressure, glomerular filtration rate, and UAE; “mesangial increase” correlated with UAE; and “interstitial scarring” correlated with diastolic blood pressure. This study provides unique documentation of renal structural abnormalities which precede clinically evident renal functional abnormalities and documents that these early structural abnormalities are present in the pre-pubertal years of diabetes as well as postpuberty, and are associated with each other in constellations that correspond to postulated mechanisms in diabetic nephropathy.

Familial syndrome of progressive arterial occlusive disease consistent with fibromuscular dysplasia, hypertension, congenital cardiac defects, bone fragility, brachysyndactyly, and learning disabilities

We report on 4 of 9 sibs with a syndrome of stenosis of the renal arteries and chronic hypertension, variable stenosis or occlusion of cerebral, abdominal and probably coronary arteries due to suspected fibromuscular dysplasia, congenital cardiac abnormalities, brachydactyly and syndactyly of the hands and feet, and increased bone fragility consistent with a mild form of osteogenesis imperfecta. Three affected individuals have had mild to moderate learning disabilities. The parents and the remaining 5 sibs have normal hands and feet and no history of excessive fractures. Individual components of this syndrome may appear as isolated conditions, including fibromuscular dysplasia, brachydactyly, syndactyly, and osteogenesis imperfecta, and are autosomal dominant traits in many cases. Explanations for this familial occurrence include autosomal recessive inheritance, autosomal dominant inheritance with decreased penetrance, or parental gonadal mosaicism for a mutation involving a single gene or several contiguous genes.

Intravenously administered labetalol for treatment of hypertension in children

Thirteen children (ages 9.2 +/- 3.7 years, mean +/- SD) received intravenous doses of labetalol, an alpha 1- and beta-adrenergic blocker, on 15 separate occasions for treatment of hypertension. In 12 of 15 episodes an initial dose of 0.55 +/- 0.34 mg/kg was given; in all 15 a continuous infusion of 0.78 +/- 0.39 mg/kg per hour was utilized for 67.3 +/- 57.1 hours. A significant decrease in systemic blood pressure occurred in all episodes (143/99.1 +/- 17.7/11.1 vs 115.6/72.4 +/- 7.7/9.5; p less than 0.01). A clinically unimportant yet statistically significant decrease in heart rate occurred during labetalol infusion (116.3 +/- 19.8 vs 107.8 +/- 11 beats/min; p less than 0.01). The episodes in children with creatinine clearances greater than 50 (n = 6) were compared with those with creatine clearances less than 20 ml/min per 1.73 m2 (n = 9); similar doses of labetalol were required for control of blood pressure. We conclude that infusion of labetalol is effective for control of blood pressure in children with hypertension, regardless of renal function.

Spectrum of disease associated with anti-neutrophil cytoplasmic autoantibodies in pediatric patients.

Anti-neutrophil cytoplasmic autoantibodies (ANCA) are usually determined during the diagnostic evaluation of systemic vasculitis and glomerulonephritis syndromes in adult patients, but few pediatric patients with ANCA have been reported. We describe five pediatric patients with ANCA and glomerulonephritis, with and without upper or lower respiratory tract disease. We compared these five patients and six previously described patients to affected adults; the spectrum of ANCA-associated disease appears to be similar in adults and children, but a female predominance may exist in the pediatric patients. Pediatric patients often had end-stage renal disease within 1 year after onset. We conclude that ANCA is a useful diagnostic tool in both pediatric and adult patients with systemic vasculitis and glomerulonephritis.

Long-Term Survival in an Infant with Urethral Atresia

Complete urethral atresia is an anomaly that previously was incompatible with life. We report on a surviving infant with this anomaly. As a fetus urinary decompression was accomplished with a vesicoamniotic shunt. Peritoneal dialysis was initiated shortly after birth and at 9 months supramembranous scrotal inlay urethroplasty was performed to provide for egress of urine from the bladder. A maternal renal allograft was performed when he was 12 months old. When the patient was 3 1/2 years old he had normal renal function and emptied the bladder to completion through the reconstructed urethra. Although mildly delayed, he continues to progress with all developmental milestones.

The impact of supplemental feeding in young children on dialysis

Abstract Supplemental feedings are commonly recommended for young children on dialysis but their effect on growth parameters and mortality has not been well documented. We report the results of a North American Pediatric Renal Transplant Cooperative Study (NAPRTCS) survey on the impact of supplemental feedings on growth and mortality in children <6 years of age at dialysis initiation. Sixty-four nonsurvivors (NonS) were matched with 110 survivors (S) for age at dialysis initiation, primary renal disease, and year of entry into the NAPRTCS database. Questionnaires were completed by participating centers on 137 patients (51 NonS, 86 S). Supplemental feedings were given to 70% of patients and more commonly given to patients <2 years of age compared to those 2–5 years of age at dialysis initiation (P<0.001). Supplemental feedings were also more commonly given to patients with nonrenal disease in addition to renal disease compared to those with renal disease only (P<0.001). In patients receiving supplemental feedings, the method of supplemental feeding was most commonly by nasogastric tube in patients <2 years of age compared to those 2–5 years of age (P=0.027). Supplemental feeding use was not different in S compared to NonS. There were no differences in height standard deviation score (SDS), weight SDS, or change in height or weight SDS in patients receiving supplemental feedings compared to those who did not. The height and weight SDS did not improve over time on supplemental feeds. In summary, despite the common use of supplemental feedings in young patients on dialysis, height, weight, and mortality remain unaffected. Prospective long-term evaluation of this therapy is needed to determine the effectiveness of supplemental feeding.

Relationship of renal size, body size, and blood pressure in children

Abstract. Somatometric parameters, renal size, and systolic blood pressure (SBP) were studied in 406 patients referred to pediatric nephrology and urology clinics. These patients included 269 females (66%), 67 African Americans (17%), and 87 patients with essential hypertension (21%). Z scores for the study population were comparable to published standards for height, kidney length, and SBP. Weight and body mass index scores were significantly greater than predicted from the standards, especially in the subset of patients with essential hypertension. Age, height, weight, body mass index, kidney length, and SBP all correlated with one another; however, on multiple regression analysis of SBP with the other five independent variables, only weight proved to have a significant correlation. Furthermore, the relationship of kidney length with SBP was positive and hypertensive patients had greater kidney size than published standards. These data do not support reduced kidney size in the population with essential hypertension, nor is there support for a convincing correlation between kidney length and SBP in the general pediatric population. Body weight correlates best with blood pressure. These findings warrant further study in a less-select population. Prevention and treatment of obesity may thus be of prime importance in addressing hypertension in children.

Glomerular Membranopathy in Children with IgA Nephropathy and Henoch Schönlein Purpura

ABSTRACT We evaluated renal biopsies from 34 children with IgA nephropathy or Henoch Schönlein purpura to further characterize the ultrastructural features of the glomerular membranopathy that occurs in these disorders. Focal glomerular basement membrane damage was identified in 29 children and was severe in 4 of the children. Alterations included focal and segmental attenuation, splitting, duplications, and spike-like subepithelial protrusions of the lamina densa, along with saccular glomerular microaneurysms arising at the paramesangium. Those cases with extensive glomerular basement membrane lesions had either moderate or severe glomerular alterations apparent by light microscopy. Over half of the cases with glomerular membranopathy had immunohistological or ultrastructural evidence of focal peripheral glomerular capillary wall immune deposits and electron-dense deposits occurred at sites of glomerular basement membrane splitting. Despite the focal attenuation of the glomerular basement membrane, we did not identify any biopsy with findings of thin basement membrane disease. The glomerular basement membrane ultrastructural findings we describe are characteristic of IgA nephropathy and Henoch Schönlein purpura, are common in children with these disorders, and are similar to the ultrastructural alterations of the basement membrane that occur in other glomerulonephritides. These basement membrane injuries may be inflammatory cell or immune mediated but their pathogenesis requires further study.

Symptomatic cerebral swelling complicating diabetic ketoacidosis documented by intraventricular pressure monitoring: survival without neurologic sequela

A six-year-old boy developed symptomatic cerebral swelling four hours after the initiation of treatment for newly diagnosed diabetes mellitus complicated by ketoacidosis. Ventriculostomy documented intracranial pressure over a two-day period. Increased intracranial pressure unresponsive to controlled hyperventilation and sedation was treated by administering a diuretic and by drainage via a ventriculostomy. Intracranial pressure monitoring was a useful adjunct in management of this rare, but often lethal, complication of diabetes mellitus. One year later, both school performance and the results of a neurologic examination were normal.