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Biomedical subjects

R A Donckerwolcke

Publications and source records attributed to R A Donckerwolcke.

At least 19 recordsLinked to original sources
PubMed2001

Pathogenesis of edema formation in the nephrotic syndrome.

Based on observations in 110 children with nephrotic syndrome (NS) and data from the literature, existing concepts on the pathogenesis of edema formation in the NS have been modified. The data suggest that the basic abnormality is a primary disturbance in renal sodium excretion. Depending on the stage in the development of the NS, the rate of progression in the development of hypoproteinemia, and the absolute levels of plasma oncotic pressure, functional hypovolemia may develop, resulting in stimulation of hemostatic mechanisms and secondary sodium retention. This applies as much to patients with minimal change NS as to patients with histological lesions. Alterations in kidney function (glomerular filtration rate, renal plasma flow, filtration fraction) in the NS cannot be explained by hypo- or hypervolemia, but reflect variations in plasma oncotic pressure and glomerular basement membrane permeability. These abnormalities will also influence sodium excretion. Evaluation of the presence of functional hypovolemia will have therapeutic consequences. A quick diagnosis can be made by assessment of FENa+ and UK+/ (UK+ + UNa+) Sodium retention associated with increased distal Na/K exchange indicates functional hypovolemia, and may be treated by albumin infusion if clinically required.

Animals↗
PubMed1999

Pathophysiology of edema formation in children with nephrotic syndrome not due to minimal change disease.

It has been shown that children with nephrotic syndrome due to minimal change disease (MCD) can present with avid salt retention and stimulated vasoactive hormones, as well as with stable edema. The present study examines these conditions in children with nephrotic syndrome not due to MCD (non-MCD). In six children with hypovolemic symptoms (congenital nephrotic syndrome in four), strong sodium retention (fractional sodium excretion, FE(Na), 0.2 +/- 0.2%) was found. Lithium clearance (FE(Li)) and maximal water excretion (Vmax) were suppressed, suggesting avid sodium reabsorption throughout the nephron. Aldosterone, renin, and norepinephrine were elevated. Sixteen other children with non-MCD had stable edema. FE(Na) was 1.8 +/- 1.1%, whereas FE(Li), Vmax, and hormones were normal, and not different from data in 35 nonproteinuric children. In children with MCD, 12 presented with hypovolemic symptoms and strong sodium retention (FE(Na) 0.3 +/- 0.3%), whereas 15 were stable (FE(Na) 1.1 +/- 0.7%). Regarding tubular sodium handling and hormones, the same distinction could be made as for the children with non-MCD. However, hypoproteinemia differed. In the children with non-MCD lesions, plasma colloid osmotic pressure was significantly lower in the hypovolemic types (4.2 +/- 0.4 mmHg) than in those with stable edema (13.0 +/- 3.8 mmHg; P < 0.05); in MCD, no such difference existed (respectively, 8.1 +/- 3.0 and 9.9 +/- 2.2 mmHg). In summary, children with nephrotic syndrome may present with pathophysiologic pictures of decreased effective circulating volume or of stable edema, regardless of whether they have non-MCD or MCD. The pathogenesis of the hypovolemic picture seems to be different, since it is associated with extreme hypoproteinemia only in the children with non-MCD.

Blood Volume↗
PubMed1996

[Henoch-Schoenlein purpura-nephritis followed by IgA-nephritis in 3 children].

In three patients, two boys of 7 and 10 and a girl of 9 years old, a kidney disease was diagnosed which evolved from Schönlein-Henoch nephritis to IgA nephropathy or Berger's disease. These two kidney diseases show striking similarities in pathological and immunological respects. Several patients have been described in the literature who suffered from both clinical pictures consecutively and of families in which different members showed either one or the other disease. A remarkable finding was the persistence of an elevated IgA serum level in all three children after the Schönlein-Henoch nephritis had subsided. These cases show the importance of long-term follow up of patients who had Schönlein-Henoch nephritis, in order to diagnose late renal complications at an early stage. They also give more evidence in favour of the assumption that Schönlein-Henoch nephritis and IgA nephropathy have a common aetiology.

Child↗
PubMed1996

Renal sodium handling in children with nephrotic relapse: relation to hypovolaemic symptoms.

We studied renal sodium handling during water diuresis in children in the early phase of relapse of minimal lesion nephrotic syndrome (MLNS). Findings were related to presence or absence of symptoms suggestive of hypovolaemia, and to neurohumoral factors, and were compared to results of similar studies in the same children in remission. Nine children (aged 7.8 +/- 3.1 years) presented with hypovolaemic symptoms, and 10 (7.4 +/- 4.3 years) without such symptoms. Both groups displayed severe proteinuria, hypoproteinaemia and oedema. Symptomatic patients showed tendency for a low glomerular filtration rate, and significantly impaired urine dilution, decreased fractional sodium and lithium excretions, and elevated diluting segment reabsorption [CH2O/(CH2O + CNa)] and sodium/potassium exchange [UK/(UK + UNa)]. In the non-symptomatic patients these parameters were normal. Plasma renin and aldosterone were significantly elevated in the symptomatic children, and strongly correlated with all parameters of tubule sodium reabsorption. Weaker associations were found for plasma noradrenaline and atrial natriuretic peptide. Vasopressin was also relatively high in the symptomatic group, but showed no association with impaired urine dilution. The diffusely stimulated tubular sodium reabsorption in the symptomatic children, in association with stimulated neurohumoral factors, indicates that secondary sodium retention contributes to oedema formation in at least a subset of children developing a nephrotic relapse. This may be limited to the early stage, and be more pronounced in some patients than in others. The tubular defect responsible for maintenance of oedema in stabilized MLNS remains unclear.

Adolescent↗
PubMed1996

A placebo-controlled, double-blind trial of growth hormone treatment in prepubertal children after renal transplant.

Sustained growth retardation in spite of a successful renal transplantation (RTx) is a serious problem for many pediatric allograft recipients. Biosynthetic growth hormone (GH) was given to 11 prepubertal children with severe growth retardation after RTx in a placebo-controlled double-blind study, assessing its effect on height velocity (HV), bone maturation, renal function, plasma IGF-I and IGF-II, serum IGF-binding proteins (IGFBP), and lipid and carbohydrate metabolism. Six months of GH (4 IU/m2/day s.c.) was either preceded or followed by six months of placebo. The patients underwent a full examination every three months. All children completed the study. Mean HV improved significantly with GH therapy (P < 0.0001), but there was also some improvement with placebo (P = 0.06). The GH-induced HV increment exceeded that of placebo by 2.9 cm/six months. Bone maturation was not accelerated. Acute renal graft rejection did not occur in any of the patients. 125I-thalamate and 131I-hippuran tests showed that mean glomerular filtration rate (GFR) and effective renal plasma flow (ERPF) did not change significantly during GH therapy. GH caused a significant increase in IGF-I (P < 0.0001), which was far greater than the insignificant increase in serum IGFBP-3 levels (P = 0.16). Mean serum levels of total cholesterol, low density lipoprotein, apolipoprotein-A1 and -B, which are elevated at the start of the study compared with that of controls, did not change significantly during GH therapy. GH induced a significant increase in mean integrated plasma insulin levels during oral glucose tolerance test, without changing plasma glucose levels. Serum fructosamine and parathyroid hormone levels remained constant. Impressive HV increment can be achieved with GH therapy in children with growth retardation after RTx, without significant changes in renal function. Bone maturation appears unaffected, suggesting an improve final height.

Adolescent↗
PubMed1996

Use of recombinant human growth hormone (rhGH) in pubertal patients with CRI/dialysis/post-transplant: Dutch data. Dutch Study Group on Growth in Children with Chronic Renal Disease.

In the intermediate term, recombinant human growth hormone (rhGH) therapy in a dose of 28-30 i.u./m2/week accelerates growth significantly in most pubertal patients with growth retardation secondary to chronic renal insufficiency (CRI), dialysis and after renal transplantation (RTx), without evidence of adverse effects or acceleration of bone maturation. Therefore, rhGH therapy may well improve the final height of these patients.

Adolescent↗
PubMed1995

Volume regulation in children with early relapse of minimal-change nephrosis with or without hypovolaemic symptoms.

The cause of sodium retention in nephrotic syndrome is unclear. Hypovolaemia has traditionally been labelled as the cause but there is evidence in adults of a renal disturbance as the main cause. We aimed to find out whether children with early nephrosis can be classified as hypovolaemic by objective measures. We measured blood volume, kidney function, and hormone concentrations in children with early relapse of minimal-change nephrosis. Three presentations could be defined. The first was patients with incipient proteinuria and normal plasma protein, characterised by sodium retention, increased renal plasma flow, and slightly increased aldosterone, but normal noradrenaline. The second was patients with severe proteinuria, hypoproteinaemia, and hypovolaemic symptoms, who had oedema, sodium retention, and high concentrations of plasma renin, aldosterone, and noradrenaline, low atrial natriuretic peptide, and low glomerular filtration rate. The third was patients with equally severe proteinuria and hypoproteinaemia, but without hypovolaemic symptoms; they had oedema, but no active sodium retention, and normal plasma hormones and glomerular filtration. Neither blood pressure nor blood volume discriminated patients with or without hypovolaemic symptoms. These findings show that children with early full-blown nephrosis can present both with and without hypovolaemic symptoms and laboratory signs, despite equally severe hypoproteinaemia, and also that sodium retention precedes the reduction in serum protein.

Adolescent↗
PubMed1995

Pulmonary hemosiderosis and immune complex glomerulonephritis.

Two children with a syndrome of pulmonary hemorrhage and immune complex nephritis are reported. Clinical history suggests that pulmonary lesions precede renal abnormalities. Necrotizing glomerulonephritis with granular immune deposits along the glomerular basement membrane was found. Although the etiology of this disease complex is still unknown, the clinical and pathological findings in these patients suggest that immune complex glomerulonephritis is an unusual complication of idiopathic pulmonary hemosiderosis.

Anti-Glomerular Basement Membrane Disease↗
PubMed1994

Growth hormone treatment in growth-retarded adolescents after renal transplant.

Growth failure is a psychosocial problem for many patients who have undergone renal transplantation. 18 adolescents (mean age 15.6, range 11.3-19.5) with severe growth retardation after renal transplantation were treated with biosynthetic growth hormone (GH) for 2 years. All received prednisone, administered daily or on alternate days, with azathioprine and/or cyclosporin A. 16 were blindly assigned to one of two GH doses (4 vs 8 IU per m2 per day). Growth, bone maturation, renal graft function, plasma insulin-like growth factors, serum binding proteins, and other biochemical parameters were checked regularly. Glomerular filtration rate and effective renal plasma flow were tested with 125I-Thalamate and 131I-Hippuran. Data on growth and glomerular filtration rate during GH treatment were also compared with those of matched non-GH-treated controls. Mean (standard deviation) increment in height after 2 years of GH was 15.7 (5.1) cm, significantly greater (p < 0.0001) than in matched controls, 5.8 (3.4) cm. Results were similar for the two GH dosage groups. Bone maturation was not accelerated. Glomerular filtration rate and effective renal plasma flow did not change significantly. The incidence of a > 25% reduction in glomerular filtration rate over 2 years was not significantly higher in GH-treated patients than in non-GH-treated controls (39% vs 32%, p = 0.97). Although a few patients had deterioration of graft function, we could not find a relation with GH treatment. Our results show that sustained improvement of height can be achieved with GH in severely growth-retarded adolescents after renal transplantation.

Adolescent↗
PubMed1994

Continuous arterial-venous diahemofiltration and continuous veno-venous diahemofiltration in infants and children.

Continuous arterial-venous diahemofiltration and continuous veno-venous diahemofiltration [CAVH(D)/CVVH(D)] in the infant and pediatric population is increasingly being utilized in the child needing renal replacement therapy (RRT). Difficulties with infant- and pediatric-specific equipment remains a limitation. The availability of techniques and equipment in this unique population is addressed. Use of this form of RRT as opposed to hemodialysis or peritoneal dialysis is discussed. The decision for CAVH(D) or CVVH(D) remains an individual choice.

Blood Flow Velocity↗
PubMed1994

Hemodialysis in infants and small children.

Hemodialysis in infants and small children requires specialized nursing staff, equipment and adequate access. The techniques, requirements and available equipment for this population are discussed.

Catheters, Indwelling↗
PubMed1994

Amino acid and carnitine supplementation in haemodialysed children.

Plasma carnitine, amino acids and lipids levels were studied in ten uraemic children treated with haemodialysis and given amino acid supplementation with and without carnitine. As carnitine is synthesised from lysine and methionine and has a significant influence on lipid metabolism, the relationship between these was examined. Amino acid supplementation (0.25 g/kg body weight) was started with the intention of improving the plasma amino acid pattern in these children and increasing the concentration of lysine, which is the substrate for carnitine synthesis. Amino acids were administered i.v. during dialysis and carnitine (25 mg/kg body weight i.v.) was administered after dialysis three times a week. Concentrations of most essential amino acids were decreased in these patients. The first period of amino acid supplementation did not increase plasma levels of the essential amino acids, with the exception of tyrosine (P < 0.01). After the second period of supplementation, methionine was increased (P < 0.01), isoleucine was decreased (P < 0.01), but tyrosine normalised and was significantly lower than after the first period (P < 0.05). Thus overall amino acid supplementation did not improve amino acid levels; it was inconsistently associated with a further decrease in high-density lipoprotein-cholesterol and an increase in total protein levels. Lysine concentrations after amino acid supplementation remained low. Paradoxically, before carnitine supplementation a positive correlation between free carnitine and triglycerides was observed.(ABSTRACT TRUNCATED AT 250 WORDS)

Adolescent↗
PubMed1994

Growth after renal transplantation in prepubertal children: impact of various treatment modalities.

A retrospective study evaluated posttransplant growth of 70 prepubertal children during the first 2 y after renal transplantation (RTx). Immunosuppressive treatment consisted of prednisone administered either daily or on alternate days in combination with either azathioprine or cyclosporin A. The increment in height standard deviation score for chronologic age during the first 2 y after RTx was less than 0.5 SD for 70% of the study population. The predictive factors for posttransplant growth were determined by evaluating several factors and treatment modalities singly and simultaneously in a multiple regression analysis. Patients with the most severe growth retardation at RTx appeared to have the most pronounced growth spurt after RTx, but even they never had complete catch-up growth, and 2 y after RTx they were still shorter than those with less severe growth retardation at RTx. Alternate-day instead of daily prednisone administration had a significantly positive influence, whereas a high cumulative dose of prednisone, azathioprine instead of cyclosporin A therapy, and a persistently reduced GFR (GFR < 50 mL/min/1.73 m2) had a significantly negative influence on catch-up growth during the 2 y after RTx. Other factors, such as gender, chronologic and bone age at RTx, primary renal disease, duration of initial dialysis, repeat RTx, and target height SD score for chronologic age, whether evaluated singly or simultaneously with other significant factors, appeared to have no significant influence on post-RTx growth. Thus, 70% of the prepubertal children do not experience appreciable catch-up growth during the first 2 y after RTx. Optimization of pretransplant height appears very important. Immunosuppressive treatment with cyclosporin therapy in combination with a minimal dose of alternate-day prednisone would then result in optimal post-transplant growth, particularly if the GFR remains above 50 mL/min/1.73 m2).

Azathioprine↗
PubMed1994

Final height and its predictive factors after renal transplantation in childhood.

A retrospective study is reported assessing final height (FH) and its predictive factors in 52 patients (31 male, 21 female) who underwent renal transplantation (RTx) before the age of 15 y. They received prednisone daily or on alternate days as well as azathioprine. The study period covered 20 y. FH remained below the third height percentile [height standard deviation score for chronologic age (hSDSCA) < -1.88] for most of these patients (77% males, 71% females). Median (range) FH was 165.0 (143.0-176.8) cm in males and 153.0 (135.0-168.4) cm in females. Median difference between FH and target height was 15.0 and 15.4 cm for males and females, respectively. For both sexes, the median hSDSCA was already below -1.88 at the start of the first hemodialysis, after which it decreased significantly until the first RTx. After RTx, there was no significant improvement of hSDSCA. The predictive factors for FH were determined by evaluating various factors simultaneous in a multiple regression analysis. This analysis provided a regression equation for predicting FH. A higher hSDSCA at the time of the first RTx and alternate-day versus daily prednisone therapy both had a significantly positive influence on FH, whereas a longer duration of reduced GFR (< 50 mL/min/1.73 m2) had a significantly negative effect on FH. Other factors such as age or bone age at first RTx, primary renal disease, duration of initial dialysis, repeat RTx, and the cumulative dose of prednisone did not influence FH significantly. In conclusion, 71-77% of patients that received their first renal transplant before the age of 15 ended up with severely short adult stature. Optimization of the hSDSCA at first RTx appears very important. Long-term administration of prednisone on alternate days would then result in optimal FH, particularly if the GFR remains above 50 mL/min/1.73 m2.

Adolescent↗