Utility of peritoneal dialysis in neonates affected by inborn errors of metabolism

Inborn errors of metabolism in neonates and pediatrics on varying dialysis modalities: a systematic review and meta-analysis

BACKGROUND

Some inborn errors of metabolism (IEMs) resulting in aberrations to blood leucine and ammonia levels are commonly treated with kidney replacement therapy (KRT). Children with IEMs require prompt treatment, as delayed treatment results in increased neurological and developmental morbidity.

OBJECTIVES

Our systematic review in neonates and pediatrics evaluates survival rates and reductions in ammonia and leucine levels across different KRT modalities (continuous KRT (CKRT), hemodialysis (HD), peritoneal dialysis (PD)).

DATA SOURCES

A literature search was conducted through PubMed, Web of Science, and Embase databases for articles including survival rate and toxic metabolite clearance data in pediatric patients with IEM undergoing KRT.

STUDY ELIGIBILITY CRITERIA

Cross-sectional, prospective, and retrospective studies with survival rates reported in patients with IEM with an intervention of CKRT, PD, or HD were included. Studies with patients receiving unclear or multiple KRT modalities were excluded.

STUDY APPRAISAL AND SYNTHESIS METHODS

Analysis variables included efficacy outcomes [% reduction in ammonia (RIA) from pre- to post-dialysis and time to 50% RIA] and mortality. The Newcastle Ottawa Risk of Bias quality assessment was used to assess bias. All statistical analyses were performed with MedCalc Statistical Software version 19.2.6.

RESULTS

A total of 37 studies (n = 642) were included. The pooled proportion (95% CI) of mortality on CKRT was 24.84% (20.93-29.08), PD was 34.42% (26.24-43.33), and HD 34.14% (24.19-45.23). A lower trend of pooled (95% CI) time to 50% RIA was observed with CKRT [6.5 (5.1-7.8)] vs. PD [14.4 (13.3-15.5)]. A higher mortality was observed with greater plasma ammonia level before CKRT (31.94% for ≥ 1000 µmol/L vs. 15.04% for < 1000 µmol/L).

CONCLUSIONS AND IMPLICATIONS OF KEY FINDINGS

Despite the limitations in sample size, trends emerged suggesting that CKRT may be associated with lower mortality rates compared to HD or PD, with potential benefits including prevention of rebound hyperammonemia and improved hemodynamic control. While HD showed a trend towards faster achievement of 50% RIA, all modalities demonstrated comparable efficacy in reducing ammonia and leucine levels.

PROSPERO REGISTRATION

CRD42023418842.

Consensus guidelines for management of hyperammonaemia in paediatric patients receiving continuous kidney replacement therapy

Hyperammonaemia in children can lead to grave consequences in the form of cerebral oedema, severe neurological impairment and even death. In infants and children, common causes of hyperammonaemia include urea cycle disorders or organic acidaemias. Few studies have assessed the role of extracorporeal therapies in the management of hyperammonaemia in neonates and children. Moreover, consensus guidelines are lacking for the use of non-kidney replacement therapy (NKRT) and kidney replacement therapies (KRTs, including peritoneal dialysis, continuous KRT, haemodialysis and hybrid therapy) to manage hyperammonaemia in neonates and children. Prompt treatment with KRT and/or NKRT, the choice of which depends on the ammonia concentrations and presenting symptoms of the patient, is crucial. This expert Consensus Statement presents recommendations for the management of hyperammonaemia requiring KRT in paediatric populations. Additional studies are required to strengthen these recommendations.

This expert Consensus Statement from the Pediatric Continuous Renal Replacement Therapy (PCRRT) workgroup presents recommendations for the management of hyperammonaemia requiring kidney replacement therapy in paediatric populations. Additional studies are needed to strengthen these recommendations, which will be reviewed every 2 years.

Short-term results of continuous venovenous haemodiafiltration versus peritoneal dialysis in 40 neonates with inborn errors of metabolism

Several recent studies have reported that toxic metabolites accumulated in the body as a product of inborn errors of metabolism (IEM) are eliminated more rapidly with continuous venovenous hemodiafiltration (CVVHDF) than with peritoneal dialysis (PD). However, there is still uncertainty about the impacts of dialysis modalities on the short-term outcome. Here, it was aimed to investigate the effects of dialysis modalities on the short-term outcome. This retrospective study included 40 newborn infants who underwent PD (29 patients) or CVVHDF (11 patients) due to inborn errors of metabolism at a tertiary centre, between June 2013 and March 2018. The outcomes and the potential effects of the dialysis modality were evaluated. Of 40 patients, 21 were urea cycle defect, 14 were organic academia, and 5 were maple syrup urine disease. The median 50% reduction time of toxic metabolites were shorter in patients treated with CVVHDF (p < 0.05). Catheter blockage was the most common complication observed in PD group (24.1%), whereas in CVVHDF group hypotension and filter blockage were more common. There was no significant difference in mortality between dialysis groups (38% vs. 45.4%, p > 0.05). In patients with hyperammonaemia, duration of plasma ammonia > 200 μg/dL was the most important factor influencing mortality (OR 1.05, CI 1.01-1.09, p = 0.007).Conclusion: This study showed that CVVHDF is more efficient than PD to rapidly eliminate toxic metabolites caused by IEM in newborn infants, but not in improving survival. What is Known: •Toxic metabolites are eliminated more rapidly with CVVHDF than with PD. •Higher complication rates were reported with rigid peritoneal catheters in PD and catheter blockage in CVVHDF. What is New: •Prolonged duration of plasma ammonia levels above a safe limit (200 μg/dL) was associated with increased mortality. •Lower catheter-related complication rates may have been associated with the use of Tenckhoff catheters in PD and the use of right internal jugular vein in CVVHDF.

Efficacy of peritoneal dialysis in neonates presenting with hyperammonaemia due to urea cycle defects and organic acidaemia

AIM

Newborns with inborn errors of metabolism can present with hyperammonaemic coma. In this study, we evaluated the effect of peritoneal dialysis on plasma ammonium levels and on the short-term outcome in neonatal patients with urea cycle defects and organic acidaemia.

METHODS

Data from infants with hyperammonaemia due to urea cycle defects or organic acidaemia treated with dialysis were collected and retrospectively analyzed. The results of patient groups (group I, survived; and group II, died) were compared.

RESULTS

Fourteen neonates were enrolled in this study. In group I, plasma ammonium levels before dialysis were median (IQR) 1652 μg/dL (1165-2098 μg/dL); in group II, they were 1289 μg/dL (1070-5550 μg/dL). There was no statistically significant difference. Urea cycle defects were diagnosed in eight, and organic acidaemia in six patients. The duration of a blood ammonia level >200 μg/dL was longer in group II (P = 0.04). A <60.8% decline in the ammonia level from the beginning of dialysis to the 12th hour of dialysis carried a 3.33-fold higher risk of mortality, when compared with a greater decline. Five patients with urea cycle defects, and one with organic acidaemia, died. The mortality risk was 8.33-fold (95% CI = 0.63-90.86) higher for patients with urea cycle defects than for those with organic acidaemia.

CONCLUSION

In patients with hyperammonaemia treated with peritoneal dialysis, the rate of ammonia removal and the underlying aetiology appear to be important prognostic factors. Neonates with organic acidaemia who are admitted to centres without continuous renal replacement therapy facilities can be effectively treated with peritoneal dialysis.

Recent advances in the treatment of hyperammonemia

Ammonia is a neurotoxic agent that is primarily generated in the intestine and detoxified in the liver. Toxic increases in systemic ammonia levels predominantly result from an inherited or acquired impairment in hepatic detoxification and lead to potentially life-threatening neuropsychiatric symptoms. Inborn deficiencies in ammonia detoxification mainly affect the urea cycle, an endogenous metabolic removal system in the liver. Hepatic encephalopathy, on the other hand, is a hyperammonemia-related complication secondary to acquired liver function impairment. A range of therapeutic options is available to target either ammonia generation and absorption or ammonia removal. Therapies for hepatic encephalopathy decrease intestinal ammonia production and uptake. Treatments for urea cycle disorders eliminate ammoniagenic amino acids through metabolic transformation, preventing ammonia generation. Therapeutic approaches removing ammonia activate the urea cycle or the second essential endogenous ammonia detoxification system, glutamine synthesis. Recent advances in treating hyperammonemia include using synergistic combination treatments, broadening the indication of orphan drugs, and developing novel approaches to regenerate functional liver tissue. This manuscript reviews the various pharmacological treatments of hyperammonemia and focuses on biopharmaceutical and drug delivery issues.