Charles L. Stewart

Posterior urethral valves in patients with Down syndrome

Renal and urological anomalies in Down syndrome (DS) have received little attention compared with the nephrourological findings described in other chromosomal abnormalities. Renal hypoplasia, hydroureteronephrosis, ureterovesical and ureteropelvic junction obstruction, and vesicoureteral reflux, but not posterior urethral valves, have been associated with DS. We report the occurrence of posterior urethral valves in three male infants with DS at a single institution. All had multiple urological procedures for correction or palliation of obstruction. Children with DS may have an increased risk for developing posterior urethral valves and obstructive uropathy. Furthermore, they may also develop chronic renal failure secondary to posterior urethral valves. Therefore, we suggests that infants with DS be screened with ultrasonography for renal and urological abnormalities early in life and, if abnormal, a contrast voiding cystourethrogram be performed to rule out posterior urethral valves or other bladder or urethral abnormalities. A review of the renal and urological anomalies in DS reported in the literature since 1960 is presented.

GROWTH HORMONE TREATMENT IN GROWTH RETARDED CHILDREN WITH END STAGE RENAL FAILURE : EFFECT ON FREE/DISSOCIABLE IGF-I LEVELS

Growth retardation in children with endstage renal disease (ESRD) is associated with normal to slightly low concentrations of insulin-like growth factor (IGF)-I and increased concentrations of IGF-binding proteins (IGFBPs) in serum. Consequently, IGF-I bioactivity is reduced in serum from uremic patients presumably due to a decrease in the concentration of free IGF-I. Improvement of linear growth with growth hormone (GH) treatment of uremic children is thought to be due to increased IGF-I/IGFBP ratio, thus resulting in increased free IGF-I levels during treatment. The purpose of the present study was to determine whether free/dissociable IGF-I levels are in fact low in uremic children and whether increased growth velocity during GH treatment is associated with an increase in the free IGF-I concentration. Serum total and free/dissociable IGF-I concentrations were measured in 5 children with ESRD before and during treatment with GH, and in control children matched for age, pubertal status, and body mass index. Height velocity increased from 3.7 +/- 1.0 cm/yr to 6.5 +/- 1.2 cm/yr with an increment in height SDS at the end of the first year of GH treatment. Free/dissociable IGF-I concentrations tended to be lower in uremic children compared to control children (3.0 +/- 0.3 vs 7.3 +/- 2.1 micrograms/l, respectively). During GH treatment, free/dissociable IGF-I levels increased significantly to 8.5 +/- 1.0 micrograms/l at 3 months and 6.9 +/- 1.4 micrograms/l at 6-24 months, p < 0.05 compared to pretreatment. Total IGF-I levels were 243 +/- 18 micrograms/l in children with ESRD before treatment and these values also increased during GH treatment (740 +/- 114 micrograms/l at 3 months and 442 +/- 44 micrograms/l at 6-24 months, p < 0.05, compared to pretreatment). Total IGF-I concentration in the control group was 439 +/- 114 micrograms/l. These results support the hypothesis that growth retardation in children with chronic renal failure is associated with a reduction in the concentration of free, biologically available IGF-I, and that increased growth velocity during GH treatment of these children is associated with restoration of free IGF-I concentrations.

Chronic peritoneal dialysis in a child with Down syndrome

Very little is known about renal failure and renal replacement therapy in patients with Down syndrome (DS) [1]. We would like to report our experience with a pediatric patient with DS who developed end-stage renal failure secondary to hemolytic-uremic syndrome, and has been treated successfully with continuous cycling peritoneal dialysis (PD) for more than 3 years. Our patient is a 14-year-old black female with DS and end-stage renal disease secondary to hemolytic-uremic syndrome. Her past medical history is significant for a ventricular septal defect which was repaired in 1982. In May 1990 she presented with vomiting, diarrhea, lethargy and decreased urine output. She was admitted to the intensive care unit for management of fluid overload, hypertension and encephalopathy; she also needed mechanical ventilation. Laboratory evaluation revealed hemolytic anemia, thrombocytopenia and uremia consistent with the hemolytic-uremic syndrome. She was started on PD, which initially functioned poorly, with poor ultrafiltration and leakage around the PD catheter, necessitating hemodialysis through a femoral catheter. Automated PD was instituted again in July 1990, with good results. Because of her difficult medical management and significant social problems she remained hospitalized until February 1991. Since then, the child has been maintained on continuous cycling PD at home with the assistance of a home nursing agency. She is tolerating dialysis well and has returned to her special education full time, in addition to attending a summer dialysis program for children. Malformations of the kidney and urinary tract in DS [2] include renal hypoplasia, hydronephrosis, ureteropelvic and ureterovesical junction obstruction, double pelvis, vesicoureteral reflux [3] and posterior urethral valves [4]. Glomerular disease has also been described in patients with DS [5, 6]. However, very little is known regarding renal failure and renal replacement therapy in this disabled population [1]. Acute renal failure may follow surgical correction of congenital heart malformation in DS [7]. Renal failure was the major cause of death in only 3.3% of institutionalized persons with DS in Texas [8]. Baird [9] and Sadovnick found only 2 patients who died of renal failure in their study of causes of death in 324 individuals with DS. Finally, patients with DS may also develop chronic renal failure secondary to congenital renal and urological anomalies. We have previously reported the association of DS and posterior urethral valves [4], and the possibility of developing chronic renal failure. Furthermore, Webb et al. [10] have recently reported two patients with DS receiving renal replacement therapy, both with functioning kidney transplants, and three patients with DS and chronic renal failure, two of them secondary to posterior urethral valves. In summary, we describe here a child with DS and endstage renal failure secondary to hemolytic-uremic syndrome who has been treated successfully with continuous cycling PD at home for more than 3 years. She is well adjusted socially and we believe is a candidate for renal transplantation. This case illustrates that PD can be performed successfully in children with DS.

IgG and IgA classes of anti-neutrophil cytoplasmic autoantibodies in a 13-year-old girl with recurrent Henoch-Schonlein purpura

We describe a 13-year-old girl with recurrent Henoch-Schonlein purpura whose symptoms were precipitated by upper respiratory tract infections. Her serum was positive for both IgG and IgA classes of anti-neutrophil cytoplasmic autoantibodies by immunofluorescence. The titers of both autoantibodies correlated with disease activity. The immunopathology underlying these findings is discussed.

Growth in Children with Renal Insufficiency

Growth failure in children with renal insufficiency has been recognized since the last century (1). However, it has only been since the advent of hemodialysis in the 1960s, chronic peritoneal dialysis in the 1970s, and the more frequent use of renal transplantation over the past 20 years that the problem of growth failure in pediatric patients with renal insufficiency has become a major concern for children whose lives have been prolonged by these therapies. Many factors have been implicated as contributing to growth retardation in children with chronic renal failure. However, a precise mechanism or unifying theory to explain the relationship between these factors and growth failure is lacking. Children with endstage renal disease may experience profound growth failure despite maximal conservative and dialysis therapies. After briefly describing normal growth patterns and measurement of growth in children, this article focuses on factors that may contribute to growth failure in children with renal insufficiency, the effect of various renal replacement therapies on growth, and newer hormonal therapy for growth retardation in children with chronic renal failure.

Megacystis-microcolon-intestinal hypoperistalsis syndrome

The megacystis-microcolon-intestinal hypoperistalsis syndrome is a congenital disorder characterized by urinary bladder distension and hypoperistalsis throughout the entire gastrointestinal tract. We present a new case with the typical clinical, radiological, and pathological findings of the syndrome. The diagnosis should be suspected in a patient who presents clinically with intestinal obstruction and urinary retention, and confirmed with imaging studies, including abdominal plain films, urinary tract ultrasonography, and contrast studies of the colon and the bladder. The prognosis is generally very poor. Our patient died secondary to sepsis on day 5 of life.

Unique Aspects of the Care of Pediatric Dialysis Patients

Renal failure and its treatment with various dialytic modalities significantly alters the physiologic and psychosocial integrity of affected individuals. When the kidneys of infants or children fail, therapy becomes more challenging and more important considering the small size and increased metabolic demands of the pediatric patient, the relative homeostasis needed for physical growth and maturation, and the complex, interpersonal interactions required in the multidisciplinary care of these patients. Estimates of the incidence of end-stage renal disease (ESRD) vary considerably with geographic area; an incidence of 3-5 new cases per million child population is found in most areas (1-3). Since the introduction of pediatric hemodialysis in the 1950s (4), intermittent peritoneal dialysis in the 1960s (9, and continuous ambulatory peritoneal dialysis in the 1970s (6), knowledge has continued to expand in this still developing field. This article will discuss some of the important considerations in the dialytic management of these children.

Fluid and Electrolyte Abnormalities in Children

Infants and children have been recognized for many years as having more frequent episodes of fluid and electrolyte disturbances than do adults; these disturbances may alter the delicate homeostasis that is normally maintained by the growing and developing human. Several characteristics of the young infant that emphasize the importance of this normally tightly regulated “salt and water” balance include 1) a larger body surface area per unit of body mass, promoting evaporative and convective, as well as conductive, losses of water via the skin; 2) a larger percentage of total body weight composed of water; 3) a higher metabolic rate, requiring more water for energy dissipation and waste product excretion; 4) in the very young infant, immaturity of certain discrete renal functions; 5) rapid utilization of body fluids; and 6) a much greater likelihood of many different types of disease processes manifesting by alterations in hydration or electrolyte status. For example, a six-month-old infant with a fever of 39–40°C will have increases in metabolic rate with increased metabolic utilization of water and will have increased insensible losses of water through the skin and the respiratory tract (with increased rate of breathing); he or she may also have increased sensible losses of water through sweating. In addition, the same sick infant is likely to have a decreased appetite, with less fluid ingested, and may have diarrheal stools and/or vomiting, with further fluid losses.