Why does three times per week hemodialysis provide inadequate dialysis for children?

Nocturnal home hemodialysis in children: Advantages, implementation, and barriers

Chronic kidney disease and end-stage renal disease (ESRD) in children are major health concerns worldwide with increasing incidence and prevalence. Renal replacement therapies and kidney transplants have remarkably improved the management of patients with ESRD in both adult and pediatric populations. Kidney transplant has the best patient outcomes, but many a time it has a considerable waiting period. In the meantime, the majority of patients with pediatric ESRD are dependent on dialysis. The conventionally utilized hemodialysis regimen is the three times weekly, in-center hemodialysis. Many studies have demonstrated the unfavorable long-term morbidity associated with the conventional regimen. Intensified dialysis programs, which include extended nocturnal hemodialysis or short daily hemodialysis, are being increasingly advocated over the past two decades. In addition to having much better clinical outcomes as compared with the conventional regimen, the flexibility to provide dialysis at home serves as a great incentive. PubMed/Medline, Embase and Cochrane databases for literature on nocturnal home hemodialysis in children with ESRD were extensively searched. Contrary to the noticeable literature available on adult home hemodialysis, a small number of studies exist in the pediatric population. In this review, the benefits, implementation and associated barriers of nocturnal home hemodialysis in children were addressed.

Strategies for Optimizing Growth in Children With Chronic Kidney Disease

Growth failure is a hallmark in children with chronic kidney disease (CKD). Therefore, early diagnosis and adequate management of growth failure is of utmost importance in these patients. The risk of severe growth retardation is the higher the younger the child is, which places an additional burden on patients and their families and hampers the psychosocial integration of these children. Careful monitoring of growth, and effective interventions are mandatory to prevent and treat growth failure in children with CKD at all ages and all stages of kidney failure. Early intervention is critical, as all therapeutic interventions are much more effective if they are started prior to the initiation of dialysis. Prevention and treatment of growth failure focuses on: (i) preservation of renal function, e.g., normalization of blood pressure and proteinuria by use of inhibitors of the renin-angiotensin aldosterone system, (ii) adequate energy intake, including tube feeding or gastrostomy in case of persisting malnutrition, (iii) substitution of water and electrolytes, especially in children with renal malformation, (iv) correction of metabolic acidosis, (v) control of parathyroid hormone levels within the CKD-dependent target range, (vi) use of recombinant human growth hormone in cases of persistent growth failure, and, (vii) early/preemptive kidney transplantation using steroid-minimizing immunosuppressive protocols in children with end-stage CKD. This review discusses these measures based on recent guidelines.

Concentrations of representative uraemic toxins in a healthy versus non-dialysis chronic kidney disease paediatric population

Background

Chronic kidney disease (CKD) in childhood is poorly explained by routine markers (e.g. urea and creatinine) and is better depicted in adults by other uraemic toxins. This study describes concentrations of representative uraemic toxins in non-dialysis CKD versus healthy children.

Methods

In 50 healthy children and 57 children with CKD Stages 1-5 [median estimated glomerular filtration rate 48 (25th-75th percentile 24-71) mL/min/1.73 m2; none on dialysis], serum concentrations of small solutes [symmetric and asymmetric dimethyl-arginine (SDMA and ADMA, respectively)], middle molecules [β2-microglobuline (β2M), complement factor D (CfD)] and protein-bound solutes [p-cresylglucuronide (pCG), hippuric acid (HA), indole-acetic acid (IAA), indoxyl sulphate (IxS), p-cresyl sulphate (pCS) and 3-carboxy-4-methyl-5-propyl-furanpropionic acid (CMPF)] were measured. Concentrations in the CKD group were expressed as z-score relative to controls and matched for age and gender.

Results

SDMA, CfD, β2M, IxS, pCS, IAA, CMPF and HA concentrations were higher in the overall CKD group compared with controls, ranging from 1.7 standard deviations (SD) for IAA and HA to 11.1 SD for SDMA. SDMA, CfD, β2M, IxS and CMPF in CKD Stages 1-2 with concentrations 4.8, 2.8, 4.5, 1.9 and 1.6 SD higher, respectively. In contrast, pCS, pCG and IAA concentrations were only higher than controls from CKD Stages 3-4 onwards, but only in CKD Stage 5 for ADMA and HA (z-score 2.6 and 20.2, respectively).

Conclusions

This is the first study to establish reference values for a wide range of uraemic toxins in non-dialysis CKD and healthy children. We observed an accumulation of multiple uraemic toxins, each with a particular retention profile according to the different CKD stages.

Unacylated ghrelin and obestatin: promising biomarkers of protein energy wasting in children with chronic kidney disease

BACKGROUND

Impairment in orexigenic/anorexigenic hormone balance may be key in the pathogenesis of protein energy wasting in children with chronic kidney disease (CKD). Measurement of ghrelin and obestatin concentrations in children with CKD would help assess the potential contribution of these hormones to uremic protein energy wasting.

METHODS

This was a cross-sectional case-control study. Acylated and unacylated ghrelin and obestatin were measured in 42 children on conservative treatment (CT), 20 children on hemodialysis, 48 pediatric renal transplant (RTx) recipients and 43 controls (CTR) (mean age 11.9, range 5-20 years). Weight, height and bicipital, tricipital, subscapular and suprailiac folds were measured, and the body mass index-standard deviation score (BMI-SDS), percentage of fat mass and fat-free mass were calculated. Urea and creatinine were measured and the glomerular filtration rate (GFR) calculated.

RESULTS

Unacylated ghrelin level was higher in patients than controls (p = 0.0001), with the highest levels found in hemodialysis patients (p = 0.001 vs. CKD-CT, p = 0.0001 vs. RTx, p < 0.0001 vs. CTR). Obestatin level was significantly higher in patients on hemodialysis than those on conservative treatment, RTx recipients and controls (p < 0.0001 in each case). Unacylated ghrelin negatively correlated with weight-SDS (p < 0.0001), BMI-SDS (p = 0.0005) and percentage fat mass (p = 0.004) and positively correlated with percentage fat-free mass (p = 0.004). Obestatin concentration negatively correlated with weight-SDS (p = 0.007). Unacylated ghrelin and obestatin concentrations positively correlated with creatinine and urea and inversely with eGFR, even after adjustments for gender, age, puberty and BMI-SDS (p < 0.0001 for each model).

CONCLUSIONS

Unacylated ghrelin and obestatin, negatively related to renal function, seem to be promising inverse indicators of nutritional status in children with CKD. Potential therapeutic implications in terms of optimization of their removal in patients on hemodialysis could be hypothesized.

The interdialytic weight gain: a simple marker of left ventricular hypertrophy in children on chronic haemodialysis

Despite multiple advances in haemodialysis (HD) technology over the years, the morbidity and mortality of HD patients remain unacceptably high. Cardiovascular disease is the most common cause of death, and left ventricular hypertrophy (LVH), seen in two-thirds of children on dialysis, is a significant contributor. The importance of volume control is increasingly recognized by nephrologists and now considered to be as important as urea kinetics, both in the day-to-day management and the long-term outcome of dialysis patients. The results published by Paglialonga et al. ( 10.1007/s00467-014-3005-2 ) in this issue of Pediatric Nephrology clearly demonstrate that there is a significant correlation between interdialytic weight gain (IDWG) and LVH in oligoanuric children on chronic HD and that children with an IDWG of >4 % are at high risk of LVH. One common practice to achieve euvolaemia is to prescribe very high ultrafiltration rates. However, both volume overload and aggressive fluid removal can induce circulatory stress and multi-organ injury. In adults, ultrafiltration rates of >1.24 % body weight per hour, even if well tolerated, are associated with a significant increase in mortality. Nephrologists should be aware of the risk of a high ultrafiltration rate, especially if tolerance is obtained by a positive dialysate-to-plasma sodium gradient. Haemodiafiltration, which allows for higher ultrafiltration rates with greater intradialytic haemodynamic stability, or more frequent and longer dialysis sessions allow for safe and effective fluid removal.