Over the past 16 years, 18 children under 2 years of age received chronic hemodialysis (HD) at our center. Five children were anuric at the start of HD and 6 had significant co-morbidity. The most ...common underlying diagnosis was posterior urethral valves. The median age at the start of HD was 12.2 months. A total of 39 episodes (defined as a discrete time period during which HD was the principle form of renal replacement therapy) of HD were performed, with a median duration of 7 months and 91.3 dialysis sessions per episode. Problems with vascular access were very common, with a revision ratio of 40%. Twenty-two line revisions were required for 36 episodes of line infection, with a median rate of line infection of 2.7 infections/patient years. The most commonly encountered organism was coagulase-negative Staphylococcus (69%). Twenty-three lines needed revision due to poor line function, despite the routine use of heparin. The effectiveness of HD was assessed in 11 patients who received HD for a continuous period of 3 or more months. The median urea reduction rate was 72%, while the parathyroid hormone levels improved to within twice the upper limit of the reference range in 69%. While there was no significant change in the median weight and height standard deviation score (SDS), the median SDS for head circumference showed significant improvement ( P=0.04). Both growth and developmental outcomes were strongly influenced by existing co-morbidity. Sixteen (89%) children were transplanted. Four (22%) children died, 3 after successful transplants. None of the deaths occurred on HD or resulted from its complications. In conclusion, HD in infants and small children is an effective and safe form of renal replacement therapy, but problems with vascular access limit its long-term use.
We report an 18-month-old girl who presented in chronic renal failure after an illness characterised by protracted diarrhoea, poor weight gain and anaemia. There were no symptoms and signs suggestive ...of a renal Fanconi syndrome, but a diagnosis of nephropathic cystinosis was suggested by renal biopsy and confirmed by an elevated leucocyte cystine concentration. We suggest that the diagnosis of cystinosis should be considered in any child with chronic renal failure of unknown aetiology.
We report our experience of the use of an immunoradiometric assay for intact parathyroid hormone (i-PTH) and the measurement of plasma ionised calcium concentration (PCa2+) in 73 children with ...chronic renal insufficiency (CRI); plasma creatinine concentration (PCr) 52-856 mumol/l. There was a poor correlation between i-PTH and PCr (r = 0.10, n = 552) compared with that for C-terminal PTH and PCr (r = 0.60, n = 248), suggesting that the i-PTH assay is independent of renal function in this group of treated children. A clear response of i-PTH to a low total plasma Ca (tPCa) and PCa2+ was observed. There was a significant positive correlation between both tPCa and PCa2+ (r = 0.50, n = 389) and the fraction of Ca2+ (the fraction of tCa which was ionised) and PCa2+ (r = 0.50, n = 389). The finding of a low or normal PCa2+ with a low calculated fraction of Ca2+ was frequently observed, i.e. the measured tPCa was unexpectedly high, suggesting complexing of Ca2+ by accumulated anions in CRI. There was a poor relationship between the plasma albumin concentration and both bound plus complexed Ca (tPCa minus PCa2+) and the fraction of Ca2+ (r = 0.15 and -0.17, respectively). The positive predictive value for a raised i-PTH of a tubular reabsorption of phosphate of less than 80% was 0.87, and of an alkaline phosphatase greater than 800 U/l was 0.37.
The optimum range for parathyroid hormone (PTH) levels in children with chronic renal failure (CRF) remains undefined. We aimed to determine growth velocity in children with CRF managed with normal ...PTH levels. We performed a retrospective case note review of 99 children (77 boys), with a glomerular filtration rate (GFR) <41 ml/min per 1.73 m(2), who had at least 2 years of 3-monthly follow-up. The age range at entry was 0.5-6.0 years; data collection was continued until 10 years of age or the commencement of growth hormone or renal replacement therapy. The median GFR was 22 ml/min per 1.73 m(2); over the study period mean serum calcium and phosphate levels were approximately equal to the mid-point of the respective normal ranges. Median PTH levels were equal to the upper limit of the normal range. Height standard deviation score (Ht SDS) at entry was -1.73. During the study period the overall mean change in Ht SDS was +0.3, significantly greater than the no change expected of a normal population ( P=0.004). The median dose of calcium carbonate was 150 mg/kg per day and 1-alpha calcidol 0.015 microg/kg per day. The growth rate was independent of all parameters, including age, PTH levels, the use of enteral feeds, and 1-alpha calcidol prescription. Our results indicate that catch-up growth can occur in infants and children with CRF when medical therapy is aimed at normalizing PTH levels.
Recent studies in adults have suggested that parenteral 1,25-dihydroxyvitamin D3 (1,25OH2D3) may have advantages over oral therapy in the management of renal osteodystrophy. The purpose of this study ...was to determine whether there were clear differences between oral and IP 1,25(OH)2D3 treatments in children who did not pose a treatment problem. Seven children (5 males, 2 females, aged 1.8 to 16 years, median 4.8 years) undergoing peritoneal dialysis were initially treated with oral 1,25(OH)2D3 for a one month equilibration period They were randomly assigned to 3 months of either oral or intraperitoneal (IP) therapy with 1,25(OH)2D3 followed by 3-months-treatment using the alternative route. No significant differences in serum creatinine, phosphate, or parathyroid hormone concentrations were found between the different routes of administration in the patients. No significant differences in height standard deviation scores or renal osteodystrophy scores were found over the six-month study. Paired oral and IP pharmacokinetic studies were performed on these 7 patients and 2 other children who had been treated for at least 2 months using either oral or IP 1,25(OH)2D3. Serum was taken prior to one of the usual 1,25(OH)2D3 doses and 0.5, 1.5, 3, 6, and 24 h afterward. The highest measured concentrations of 1,25(OH)2D3 were found at 1.5 h for both oral and IP treatments (mean Cmax SD: oral 116 23 pmol/l, IP 121 24 pmol/l, p > 0.05). The AUC's for oral and IP therapy were similar (1701 276 and 1645 301 pmol/h/l, respectively). In the paired pharmacokinetic studies no significant differences were found between oral and IP treatments for the serum half life (27.4 11.6 h and 19.2 8.1 h, respectively) and total body clearance (15.3 2.1 h and 18.4 3.3 h, respectively) of 1,25(OH)2D3. In children who respond appropriately to oral 1,25(OH)2D3 there is no biological advantage to the use of IP 1,25(OH)2D3.
Peritoneal dialysis provides a convenient means of administering calcitriol. We investigated in vitro the efficiency with which this approach would deliver the drug to patients. We used an injectable ...preparation of calcitriol, Calcijex (Abbott Laboratories, Montreal, Quebec, Canada), which we radiolabelled by adding radioactive 1,25-dihydroxyvitamin D3 to it. The preparation was injected into dialysis bags and drained through appropriate tubing to monitor delivery of the radiolabelled calcitriol. By 2 h after injecting calcitriol into dialysis bags, 50% of the dose was left in the fluid, by 20 h only 26% was left. The delivered drug was pure 1,25-dihydroxyvitamin D3 based on chromatographic analysis of the recovered radiochemical. To study what would happen if the drug was in the bag for a minimal length of time the calcitriol was injected immediately prior to draining the fluid. We recovered 62.9% +/- 5.2% SD of the dose from the tubing which would theoretically have entered a patient. There was no significant change in calcitriol dose delivered if the fluid was warmed to 37 degrees C prior to injecting the drug and immediate drainage of the bag.
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