Oxalate elimination via hemodialysis or peritoneal dialysis in children with chronic renal failure

Oxalate elimination and oxalate dialysance via hemodialysis (HD) or peritoneal dialysis (CAPD) has not been studied in detail in pediatric patients. We studied plasma oxalate, oxalate elimination, and oxalate dialysance in 15 infants and children undergoing CAPD (9 female, 6 male, aged 9 months to 18 years) and in 10 children on HD (4 female, 6 male, aged 7-18 years). Two children in each group had primary hyperoxaluria (PH). The mean duration of dialysis prior to examination was 12 +/- 11 months in CAPD and 31 +/- 23 months in HD patients. Bicarbonate HD was performed 5 h three times a week, CAPD consisted of five daily exchanges in 5 patients and four changes in the remaining 10 children (dwell volume 40 ml/kg body weight, 2.3 g/l glucose). Although oxalate dialysance was significantly higher in HD (mean 115.6 ml/ min per 1.73 m2 in HD versus 7.14 ml/min in CAPD), mean oxalate elimination per week was not different between both renal replacement therapies (3,478 mumol/1.73 m2 surface area/week in CAPD versus 3,915 mumol/1.73 m2 per week in HD). Oxalate elimination in patients with PH was between 6,650 and 9,900 mumol/week. Plasma oxalate remained elevated in both procedures [28-84 mumol/l in CAPD (92/148 in PH) and 33-101 mumol/l in HD (70/93 in PH)]. Oxalate elimination can be increased by a more frequent hemodialysis regimen.

Impact of uraemia on food efficiency and the pulsatile mode of growth hormone secretion in rats

In view of the profound growth failure resulting from renal insufficiency and uraemia, the present studies were designed to specifically investigate food efficiency and the pattern of GH secretion under these conditions. Animals were made uraemic by 5/6 nephrectomy (Nx) and feeding a high-protein diet. Three groups of animals were studied: uraemic (Ur); sham-operated, fed ad libitum (Sh); and sham-operated pair-fed with the uraemics (PF). Food intake per 100 g body weight and food efficiency (g weight gained per g food consumed) were calculated. Fourteen days after 5/6 Nx, blood samples were taken via intra-atrial catheters at 10-min intervals over a period of 6 h. GH was measured in plasma by radioimmunoassay. GH pulsatility was analysed by multiple parameter deconvolution. The growth rate of Ur animals was significantly lower than that of Sh. The body weights of the Ur animals were also lower than PF due to an initial period of weight loss. Both Sh and PF animals showed the typical negative slope of food intake as body weight increased. In contrast, the Ur animals showed a positive slope of food intake. The lower rate of growth and the elevated food intake corresponded to a decreased food efficiency for the Ur group. Deconvolution analysis of pulsatile GH release demonstrated a significant increase in GH half-life in the Ur animals. The amplitude and mass of GH secretory pulses were decreased, whereas the number of detectable secretory bursts was increased. These changes were specific to uraemia with respect to half-life and number of pulses.(ABSTRACT TRUNCATED AT 250 WORDS)

Hypercholesterolemia and growth hormone in renal diseases

The interrelationships of hypercholesterolemia, progression of renal disease to renal failure, and to risks of nephrotic syntrouse are emerging. Both hypercholesterolemia and growth hormone are progression factors, and, in the chronically nephrotic patient, these factors may help to explain the progression to renal failure. Treatment of such patients with growth hormone even though growth retarded should be approached with caution.

Implementation of a program model to develop specialty staff resource nurses in genetics

A CNS program to develop staff resource nurses in the specialty area of genetics was implemented. The purpose of the program was to provide staff nurses with necessary knowledge and skills to improve identification of and services for clients with genetic conditions. Twenty-eight staff nurses completed the program, which consisted of a 2-day workshop, a 3-month preceptorship, and regularly scheduled continuing education meetings. Pre- and postworkshop test scores indicated a significant gain in nurses' knowledge of genetic concepts and resources. Resource nurses' interventions with genetic clients increased 3 and 6 months after the workshop. Staff nurse-to-CNS referral of genetic clients continued to increase 3 and 6 months after the workshop. The described program can be used as a model by CNSs in other settings and specialty areas.

Transplantation for primary hyperoxaluria in the USA

US data were sought for transplantation in primary hyperoxaluria (PH). The USRDS recorded 194 patients since 1974. By lifetable analysis, survival was better for transplanted than for non-transplanted patients (P < 0.001), even after trimming data for age < 55 and end-stage renal disease since 1985 (63 patients, 39 transplanted, 24 not transplanted). Transplant survival was longer for living related donor (21) vs cadaveric (17) transplants. Twenty-nine kidney transplants in 22 children were registered in NAPRTCS. Interview data with physicians showed that eight of 17 living related donor kidneys functioned well, three were borderline and six were lost. All six cadaver kidneys were lost. Four of six kidney-liver transplants functioned, and two died. United Network for Organ Sharing recorded 13 kidney-liver transplants in 11 patients. Six initially functioned well; two were retransplanted. Ultimately seven lived and four died. Overall, transplant is better than no transplant; cadaver donation results are poor; living related kidney donation can succeed; and kidney-liver transplant is still problematic in the US, and rarely follows appropriate investigation. Until more cooperative effort can be achieved, isolated kidney living related donor transplant is preferable, and does not preclude kidney-liver transplant later.

Selection of transplantation procedures and perioperative management in primary hyperoxaluria type 1

This paper outlines the different options of transplant procedures in patients with primary hyperoxaluria type 1. Isolated kidney, isolated liver and combined liver-kidney grafting are discussed. Combined liver-kidney grafting appears to be the preferred treatment for patients already in end-stage renal failure. The potential value of the two other procedures is outlined. Guidelines for perioperative care are given. These involve fluid regime, pyridoxine supplementation, immunosuppression and administration of crystallization inhibitors such as phosphate and citrate. Special emphasis is put on selection of appropriate dialysis procedures and reasons why haemodialysis and continuous haemodiafiltration are the methods of choice.

Nephrosis in childhood

Succinct aspects of clinical features, pathophysiology and prognosis of nephrotic syndrome in childhood, and indications for performing renal biopsy are enumerated in this review. Orthodox treatment of the nephrotic syndrome with more recent therapeutic approaches, and the role of diuretics, albumin infusions and immunizations in patients with the nephrotic syndrome are reviewed. The etiology of peritonitis, acute renal failure, and renal transplantation are re-examined to update nephrologists on the associated complications of this common childhood disease.

Preanesthetic medication with intranasal midazolam for brief pediatric surgical procedures. Effect on recovery and hospital discharge times

BACKGROUND

The perfect preanesthesia medication and its ideal route of administration are still debated, but for pediatric surgical patients undergoing brief procedures, preanesthesia medication is frequently omitted because of the concern that it will prolong the child's recovery from anesthesia. The effects of nasally administered midazolam on anesthetic recovery and hospital discharge times were determined in 88 ASA physical status 1 and 2 ambulatory surgical patients undergoing a brief surgical procedure.

METHODS

Using a randomized, double-blind, placebo-controlled design, 88 ambulatory surgical patients 10-36 months of age undergoing myringotomy and tube insertion were entered into the study. All patients were randomly assigned to one of three medication groups. One group received 0.2 mg/kg intranasal midazolam; a second group received 0.3 mg/kg intranasal midazolam; and the third group received intranasal saline drops. All patients were anesthetized with nitrous oxide, oxygen, and halothane administered via mask. The duration of anesthesia lasted between 9 and 10 min. After preanesthetic medication, the children were evaluated for ease of separation and induction of anesthesia. In addition, the time from when the anesthetic was discontinued until the child recovered from anesthesia and the time the child was discharged home were recorded by a nurse observer blinded to the patient grouping.

RESULTS

Children receiving midazolam had smoother, calmer parent-child separation and anesthesia induction scores, and their anesthesia recovery times and hospital discharge times were the same as those receiving placebo.

CONCLUSIONS

For children undergoing brief surgical procedures, nasal midazolam provides satisfactory anxiolysis without delaying anesthesia recovery and hospital discharge.

Effects of deflazacort and cortisone on body growth, thymus weight and gene expression of growth-related proteins in the rat

Deflazacort is an oxazoline derivative of cortisone with presumably less serious side effects, but its effects on growth factors are unknown. The present experiments in Long Evans rats were carried out to investigate how deflazacort administration affected the growing rat, especially in relation to hepatic insulin-like growth factor I (IGF-I) and growth hormone receptor (GHR) messenger ribonucleic acid (mRNA). Four groups of animals were used: those treated with cortisone, with two different doses of deflazacort and with vehicle. Subcutaneous injections were given daily for 8 days. Thymus weight was reduced in all treated groups, with a comparable magnitude of reduction in the groups treated with cortisone and the higher dose of deflazacort (DF1). Daily weight gain was reduced significantly after cortisone treatment, but less so in the DF1 rats. Liver IFG-I and GHR mRNA were lower in the cortisone and deflazacort than in controls. However, GHR mRNA was reduced significantly only by cortisone and not by DF1. We conclude that growth failure is less severe in the DF1 rats compared to cortisone rats, which corresponds to the reduction in hepatic GHR mRNA.

Cerebral ultrasonography before and after cardiac surgery in infants

Cerebral ultrasonography was performed in 66 infants before and after open heart surgery in order to study the incidence of cerebral complications. The underlying cardiac malformations were ventricular septal defect (n = 28), transposition of the great arteries (n = 11), tetralogy of Fallot (n = 8), complete atrioventricular septal defect (n = 5), total anomalous pulmonary venous drainage (n = 3), truncus arteriosus communis (n = 2), and complex cardiac malformations (n = 9). In 60 of the 66 infants ultrasonography of the brain preoperatively was normal, 3 had minor structural abnormalities, and 3 had ventriculomegaly of various degrees. Postoperatively, 46 infants had a normal brain ultrasound scan; 6 had slight structural abnormalities; and 5 had slight symmetric or asymmetric widening of the ventricles. Five infants showed severe ventriculomegaly with cerebral atrophy, and in 4 patients there was intracerebral hemorrhage, associated in 2 cases with severe ventriculomegaly. On repeat examinations it was found that up to 4 weeks after the operation an initially normal cerebral ultrasound scan could convert to a pathologic one. Most of those children who showed significant deterioration on the cerebral ultrasound scan suffered from complex cardiac malformations or had severe problems during the postoperative period.

Continuous arteriovenous haemofiltration in critically ill children

We report 24 children with acute renal failure treated with continuous arteriovenous haemofiltration (CAVH) between 1987 and 1991. The median age was 2.9 years (range 3 days to 9 years). The main causes of the acute renal failure were: open heart surgery (n = 11) and liver failure of different origins before and after liver transplantation (n = 10). The indication for CAVH was oliguria or fluid overload in all children. The femoral vessels were used as vascular access in most instances. Different filters were used, depending on the size of the patient and an average ultrafiltration of 130 +/- 89 ml/h was achieved, which resulted in a fluid clearance of 4.0 +/- 2.6 ml/min per 1.73 m2. In 18 patients uraemia was adequately controlled. Nine children survived after recovery of their renal function; 15 (62.5%) died as a consequence of multiorgan failure. We conclude that CAVH is an effective method to support critically ill children with acute renal failure.

Recovery characteristics of desflurane versus halothane for maintenance of anesthesia in pediatric ambulatory patients

BACKGROUND

Desflurane is a new potent, inhaled anesthetic agent with low blood-gas solubility that should allow for the rapid induction of and emergence from anesthesia. However, its extreme pungency makes desflurane unacceptable for induction of anesthesia in children. This study was undertaken to determine the airway properties of desflurane administered by mask after anesthetic induction with halothane and nitrous oxide, and to compare the emergence and recovery properties of minimum alveolar concentration (MAC)-equivalent concentrations of desflurane or halothane in nitrous oxide in pediatric patients undergoing ambulatory surgery.

METHODS

Forty-five children undergoing ambulatory surgery for inguinal hernia repair, orchiopexy, and/or circumcision were randomized into two groups. Both groups were premedicated with intranasal midazolam and given halothane and nitrous oxide by mask to induce anesthesia. A caudal block was placed in children in both groups after anesthetic induction. For maintenance of anesthesia, group I patients (n = 22) were switched over to desflurane (1 MAC) and nitrous oxide, and group II patients (n = 23) continued to receive halothane (1 MAC) and nitrous oxide. All patients breathed spontaneously throughout the entire procedure, and all anesthetics were terminated abruptly at the conclusion of surgery. Recovery indicators (time to first response, length of time in the recovery room and length of time in the hospital) and the quality of the anesthetic emergence were assessed by a nurse blinded to each patient's anesthetic. This observer was present with the patient throughout his or her ambulatory hospitalization and continuously assessed the recovery indicators according to preset criteria.

RESULTS

The groups did not differ with respect to age, weight, or dose of midazolam. Although group I (desflurane) had a longer anesthesia time (52 +/- 12 min vs. 42 +/- 10 min), their time to first response (9.5 +/- 6.8 min vs. 20.9 +/- 14.7 min) and their recovery room time (21 +/- 10.7 min vs. 29 +/- 14.6 min) were less than those in group II (halothane). There was a trend for patient emergence from desflurane anesthesia to be associated with a higher incidence of emergence delirium (50% vs. 21%). The two groups were similar with respect to overall duration of postoperative ambulatory hospitalization.

CONCLUSIONS

In children premedicated with intranasal midazolam, desflurane maintenance anesthesia allows for a faster recovery. However, depending on the institution's criteria for ambulatory surgical patient discharge, desflurane may or may not affect the overall hospitalization time.

Determination of oxalate excretion in spot urines of healthy children by ion chromatography

Evidence for the suitability of spot urines for selective screening in children was obtained by comparing the 24-hour urinary oxalate excretion with the ratio of urinary oxalate to creatinine [mmol/mol] in spontaneously voided urine samples. Spot urines of 169 healthy children aged 1 day to 13 years were analysed in order to establish reference values for the urinary oxalate/creatinine ratio in relation to age and body surface area. Oxalate was measured by automated ion chromatography. Results showed an inverse relationship between the oxalate/creatinine ratio and age. The highest ratios, 131 +/- 57 mmol/mol (mean +/- 2 SD), were found in infants. At age two years, the ratio was 84 +/- 55, at age five years 56 +/- 35, and for children older than ten years 42 +/- 31. This finding can be explained by the gain of muscle mass and hence increased creatinine production with increasing age. Data for the urinary oxalate/creatinine ratio are presented according to body surface area for the assessment of children with abnormal growth. In 19 urine samples from nine patients with primary hyperoxaluria, the oxalate/creatinine ratio greatly exceeded (286-2022 mmol/mol) the above reference ranges. We therefore propose the determination of the oxalate/creatinine ratio in spot urines for the selective screening for hyperoxaluria in children with nephrocalcinosis or urolithiasis.

Anti-proliferative effects of deflazacort on Nb2 cells as quantitated by formazan production

Prolactin and other lactogenic hormones are mitogenic for the rat T-cell lymphoma line, Nb2. Glucocorticoids have antiproliferative effects on these cells. A limiting feature of experiments utilizing the Nb2 line is their labor-intensive nature. We therefore adapted the commonly used MTT dye proliferation assay for the Nb2 cell line. While rPRL, hPRL, oPRL, hGH, bPL, and to a lesser extent bPRL stimulated the Nb2 cells, hormones without lactogenic activity, rGH and oGH did not. Human serum and rat sera from animals bearing a PRL-secreting tumor stimulated the Nb2 cells in parallel to standards. Glucocorticoids had anti-proliferative effects on Nb2 cells in the presence of half-maximal or maximal PRL doses, as measured by the MTT proliferation assay. It has been claimed that an oxazoline steroid, deflazacort, has anti-inflammatory effects in clinical studies with fewer of the deleterious side-effects common to glucocorticoids. We therefore compared the in vitro anti-proliferative effects of deflazacort with other glucocorticoids. Deflazacort's negative effect on Nb2 cell proliferation was similar to that of cortisol and prednisolone and less than that of dexamethasone. We conclude that the MTT proliferation assay can be used to study both mitogenic and anti-proliferative substances in Nb2 cells. In addition we found that deflazacort acts similarly in vitro to other glucocorticoids.

Therapeutics of X-linked hypophosphatemic rickets

X-linked hypophosphatemia, the most common form of familial rickets, is conventionally treated with 1,25-dihydroxyvitamin D3 (5-50 ng/kg per day) plus phosphate supplementation (70-100 mg/kg per day). However, nephrocalcinosis is noted in many children treated with this therapy. Whether to treat or not and whether such treatment should be continued into adulthood or in pregnancy are unsettled questions. This article reviews these controversies and provides current recommendations.

Perturbations in potassium balance

Hyperkalemia and hypokalemia are commonly encountered in medical practice. Differential diagnosis and therapeutic approaches have been presented to provide an informed choice for the practicing physician.

[Has post-streptococcal glomerulonephritis disappeared?]

We report on 21 children with poststreptococcal glomerulonephritis (PSGN). The diagnosis was based on clinical and laboratory criteria. 19/21 had a clinically apparent throat infection initially, but only 6 received antibiotic treatment. Initial symptoms were: macrohematuria (20/21), edema (10/21), arterial hypertension (6/21), reduced creatinine-clearance (11/21), and proteinuria (18/21). No Patient was dialyzed. After an interval of 0.3 to 25 months 19 children are asymptomatic. All patients have normal creatinine-clearances; none is hypertensive. The present data show that PSGN has not disappeared in Mid-Europe. Remarkable acute disturbances occurred, which healed in almost all cases. The importance of accurate bacteriologic diagnosis and adequate therapy is emphasized.

Continuous peritoneal dialysis in children

During the period from June 1985 to December 1991, 48 children were treated with continuous peritoneal dialysis (CPD) in our centre because of acute renal failure. The median age was 1.8 years (range 0.01-17.1). The most common diagnoses were: hemolytic uremic syndrome (n = 22), anuria after cardiac surgery (n = 7), and septicemia with multiorgan failure (n = 7). Kidney function recovered in 35 (73%); 13 (27%) died of their original disease. One further patient with HUS recovered from dialysis but died of cerebral complications shortly afterwards. One patient remained anuric and requires renal replacement therapy. Hyperkalemia, when present initially, and uremia could be controlled adequately in all cases. However, ultrafiltration posed problems when cardiac output was low. Peritonitis occurred in 11 patients; in 8 children the Tenckhoff catheter had to be revised because of leakage (5), flow problems (2), or bowel perforation (1). CPD proved to be an excellent method to treat acute renal failure in children of all age groups. The rate of complications was acceptable.

Treatment of inherited metabolic disorders by liver transplantation

Among the worldwide accepted indications for liver transplantation, inherited metabolic disorders play an increasing role. In some paediatric centres this indication runs second after extrahepatic biliary atresia. The aim of liver transplantation in inherited metabolic disorders is twofold: the first is to save a patient's life, the second is to accomplish phenotypic and functional cure of his disease. These aims may be achieved in disorders presenting with cirrhosis, hepatoma, life-threatening progression or failure of other organs with preserved liver function. The timing of liver transplantation has become easier with development of surgical techniques of reduced-size donor livers. These techniques enable the performance of liver transplantation with ABO blood group compatible organs of almost any size if indicated either by deterioration of liver function or impending complications such as hepatoma or life-threatening progression. In comparison with other indications such as extrahepatic biliary atresia, postnecrotic liver cirrhosis or acute liver failure, the results of transplantation in patients with inherited metabolic disorders seem to be better, reaching up to 78-95% actuarial 1-year survival rates. However, lifelong immunosuppressive therapy is necessary. This seems to be acceptable even in disorders with only partial liver function defects.

Efficacy of calcium carbonate and low-dose vitamin D/1,25(OH)2D3 in reducing the risk of developing renal osteodystrophy in children on continuous ambulatory peritoneal dialysis

Eight children with terminal renal insufficiency on continuous ambulatory peritoneal dialysis were followed for 12 months to evaluate laboratory parameters of mineral ion and bone metabolism. Calcium carbonate (range 47-295 mg/kg body weight per day) was given in combination with low doses of either vitamin D or 1,25(OH2D3. Blood urea nitrogen and serum phosphate concentrations remained well controlled throughout the observation period. A significant increase in serum calcium levels from 2.35 +/- 0.18 to 2.61 +/- 0.22 mmol/l (mean +/- SD) was observed during the first 6 months. Alkaline phosphatase activity and mid-C-regional parathyroid hormone, both indirect parameters of bone metabolism, revealed no evidence of severe secondary hyperparathyroidism. Our data indicate that calcium carbonate may be sufficient to induce relative hypercalcaemia in uraemic children, and thus reduce the risk of developing renal osteodystrophy. Unwanted side-effects of vitamin D preparations, i.e. increased intestinal phosphate absorption and hypercalcaemia after successful renal transplantation, may thus be avoided.

One year's experience with recombinant erythropoietin in children undergoing continuous ambulatory or cycling peritoneal dialysis

Fourteen patients (aged 5.9-22.1 years) undergoing continuous ambulatory or cycling peritoneal dialysis were treated with recombinant human erythropoietin (rhEPO), which was given intravenously once a week at a dosage of 300 units/kg. The mean haematocrit level increased from 18.5% to 27.5% and the reticulocyte count from 19% to 62% within 1 month. After an average time of 3.1 months rhEPO dosage could be adjusted to 100 units/kg per week to keep the haematocrit level at 30%. Only 1 patient had an exacerbation of hypertension, which required a dosage reduction; other side-effects were not noted.

Evidence suggesting hyperoxaluria as a cause of nephrocalcinosis in phosphate-treated hypophosphataemic rickets

Urinary excretion of oxalate and phosphate was measured in twelve vitamin-D-treated, phosphate-supplemented patients with X-linked hypophosphataemia (XLH; four children, eight adolescents and adults) to investigate possible causative factors of nephrocalcinosis other than calcium. Oxalate excretion correlated highly with urinary phosphate excretion and with intake of phosphate supplements corrected for body surface area. Young children received the highest relative doses of phosphate (range 2.27-10.8 g/1.73 m2 daily) and their urinary oxalate excretion was very high (0.94-3.38 mmol/1.73 m2 daily). The urinary oxalate excretion of untreated adults with XLH was within normal limits. Six patients had evidence of nephrocalcinosis on ultrasound. The high urinary oxalate excretion in phosphate-supplemented XLH may be seen as a special type of enteric hyperoxaluria, in which the conditions of calcium-oxalate crystal precipitation could be reached even at normal levels of urinary calcium excretion. Urinary excretion of both calcium and oxalate should therefore be monitored during treatment in young XLH patients.

Primary hyperoxaluria type I

Primary hyperoxaluria type I is a metabolic disorder caused by the deficiency of the peroxisomal alanine:glyoxylate aminotransferase. The disease is inherited as an autosomal recessive trait. The clinical course is outlined based on data from 330 published cases. Diagnostic cornerstones are clinical parameters, urinary excretion of oxalate and glycolate, and the determination of enzyme activity in liver tissue. Principles of conservative treatment, e.g. volume load and pyridoxine substitution, are described as well as experience with different modes of dialysis and transplantation. Kidney transplantation is associated with a high rate of recurrence of the original disease despite excellent management resulting in many instances in early graft loss. Liver transplantation offers the possibility to correct the metabolic defect and to prevent the progression of crystal deposition in the body.