Efficacy and safety of intermittent hemodialysis in infants and young children with inborn errors of metabolism

Renal Replacement Therapy in Methylmalonic Aciduria-Related Metabolic Failure: Case Report and Literature Review

BACKGROUND

Methylmalonic Aciduria (MA) without homocystinuria (or isolated MA) is a group of rare inherited metabolic disorders which leads to the accumulation of methylmalonic acid (MMA), a toxic molecule that accumulates in blood, urine, and cerebrospinal fluid, causing acute and chronic complications including metabolic crises, acute kidney injury (AKI), and chronic kidney disease (CKD). Detailed Case Description: Herein, we report a case of a 39-year-old male with MA and stage IV CKD who experienced acute metabolic decompensation secondary to gastrointestinal infection. The patient underwent a single hemodialysis (HD) session to correct severe metabolic acidosis unresponsive to medical therapy and to rapidly remove MMA. The HD session resulted in prompt clinical improvement and shortening of hospitalization.

DISCUSSION

MMA accumulation in MA patients causes acute and life-threatening complications, such as metabolic decompensations, and long-term complications such as CKD, eventually leading to renal replacement therapy (RRT). Data reported in the literature show that, overall, all dialytic treatments (intermittent HD, continuous HD, peritoneal dialysis) are effective in MMA removal. HD, in particular, can be useful in the emergency setting to control metabolic crises, even with GFR > 15 mL/min. Kidney and/or liver transplantations are often needed in MA patients. While a solitary transplanted kidney can be rapidly affected by MMA exposure, with a decline in renal function even in the first year of follow-up, the combined liver-kidney transplantation showed better long-term results due to a combination of reduced MMA production along with increased urinary excretion.

CONCLUSIONS

Early diagnosis, multidisciplinary management and preventive measures are pivotal in MA patients to avoid recurrent AKI episodes and, consequently, to slow down CKD progression.

Acute hemodialysis therapy in neonates with inborn errors of metabolism

BACKGROUND

Inborn errors of metabolism (IEM), including organic acidemias and urea cycle defects, are characterized by systemic accumulation of toxic metabolites with deleterious effect on the developing brain. While hemodialysis (HD) is most efficient in clearing IEM-induced metabolic toxins, data regarding its use during the neonatal period is scarce.

METHODS

We retrospectively summarize our experience with HD in 20 neonates with IEM-induced metabolic intoxication (seven with maple syrup urine disease, 13 with primary hyperammonia), over a 16-year period, between 2004 and 2020. All patients presented with IEM-induced neurologic deterioration at 48 h to 14 days post-delivery, and were managed with HD in a pediatric intensive care setting. HD was performed through an internal jugular acute double-lumen catheter (6.5-7.0 French), using an AK-200S (Gambro, Sweden) dialysis machine and tubing, with F3 or FXpaed (Fresenius, Germany) dialyzers.

RESULTS

Median (interquartile range) age and weight at presentation were 5 (3-8) days and 2830 (2725-3115) g, respectively. Two consecutive HD sessions decreased the mean leucine levels from 2281 ± 631 to 179 ± 91 μmol/L (92.1% reduction) in MSUD patients, and the mean ammonia levels from 955 ± 444 to 129 ± 55 μmol/L (86.5% reduction), in patients with hyperammonemia. HD was uneventful in all patients, and led to marked clinical improvement in 17 patients (85%). Three patients (15%) died during the neonatal period, and four died during long-term follow-up.

CONCLUSIONS

Taken together, our results indicate that HD is safe, effective, and life-saving for most neonates with severe IEM-induced metabolic intoxication, when promptly performed by an experienced and multidisciplinary team. A higher resolution version of the Graphical abstract is available as Supplementary information.

Review: Neonatal dialysis is technically feasible but ethical and global issues need to be addressed

AIM

Our aim was to look at the technical, ethical and global issues related to neonatal dialysis.

METHODS

We performed a PubMed research on manuscripts published from March 2010 to March 2020 and retrospectively reviewed all neonates who received dialysis in our French paediatric and neonatal intensive care units from April 2009 to March 2019.

RESULTS

Dialysis is performed on neonates with pre-existing renal diseases, acute kidney injuries or inborn errors of metabolism. It is required in 0.5%-1% of neonates admitted to the neonatal intensive care units. Peritoneal dialysis and extracorporeal blood purification are both feasible, with more complications, but the results are close to those obtained in older infants, at least in children without multi-organ dysfunction. Novel haemodialysis machines are being evaluated. Ethical issues are a major concern. Multidisciplinary teams should consider associated comorbidities, risks of permanent end-stage renal disease and provide parents with full and neutral information. These should drive decisions about whether dialysis is in child's best interests.

CONCLUSION

Neonatal dialysis is technically feasible, but ethically challenging, and short-term and long-term data remain limited. Prospective studies and dialysis registries would improve global management and quality of life of these patients at risk of chronic kidney disease.

Management of 35 critically ill hyperammonemic neonates: Role of early administration of metabolite scavengers and continuous hemodialysis

Neurological involvement is frequent in inherited metabolic disease of the intoxication type. Hyperammonemic coma related to these diseases may cause severe neurological sequelae. Early optimal treatment is mandatory combining metabolite scavengers (MS) and sometimes continuous veno-venous hemodialysis (CVVHD). We aimed to describe the therapeutic management of hyperammonemia in neonates upon diagnosis of their metabolic disease and to compare neonates managed with MS alone or with both MS and CVVHD. We conducted a retrospective study including all neonates admitted for initial hyperammonemia to the pediatric intensive care unit of a Reference Center of Inherited Metabolic Diseases, between 2001 and 2012. The study included 35 neonates. Before admission, MS were initiated for 11 neonates. At admission, the median ammonia levels were 391 μmol/L and were significantly lower in neonates who received MS before admission. At admission, ammonia levels were 644 μmol/L in dialyzed and 283 μmol/L in non-dialyzed neonates. The median time to reach a 50% decrease of the initial ammonia levels was significantly shorter in dialyzed neonates; however, the normalization of ammonia levels was similar between dialyzed and non-dialyzed neonates. Hemodynamic disorders were more frequent in dialyzed neonates. CONCLUSION: MS represent an effective treatment for hyperammonemia and should be available in all pediatric units to avoid the need for CVVHD. Although CVVHD enhances the kinetics of toxic metabolite decrease, it is associated with adverse hemodynamic effects.

Suggested guidelines for the diagnosis and management of urea cycle disorders: First revision

In 2012, we published guidelines summarizing and evaluating late 2011 evidence for diagnosis and therapy of urea cycle disorders (UCDs). With 1:35 000 estimated incidence, UCDs cause hyperammonemia of neonatal (~50%) or late onset that can lead to intellectual disability or death, even while effective therapies do exist. In the 7 years that have elapsed since the first guideline was published, abundant novel information has accumulated, experience on newborn screening for some UCDs has widened, a novel hyperammonemia-causing genetic disorder has been reported, glycerol phenylbutyrate has been introduced as a treatment, and novel promising therapeutic avenues (including gene therapy) have been opened. Several factors including the impact of the first edition of these guidelines (frequently read and quoted) may have increased awareness among health professionals and patient families. However, under-recognition and delayed diagnosis of UCDs still appear widespread. It was therefore necessary to revise the original guidelines to ensure an up-to-date frame of reference for professionals and patients as well as for awareness campaigns. This was accomplished by keeping the original spirit of providing a trans-European consensus based on robust evidence (scored with GRADE methodology), involving professionals on UCDs from nine countries in preparing this consensus. We believe this revised guideline, which has been reviewed by several societies that are involved in the management of UCDs, will have a positive impact on the outcomes of patients by establishing common standards, and spreading and harmonizing good practices. It may also promote the identification of knowledge voids to be filled by future research.

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.

Continuous Renal Replacement Therapy for Treatment of Severe Attacks of Inborn Errors of Metabolism

Severe metabolic crises in children with inborn errors of metabolism can result in mortality or severe morbidities where continuous renal replacement therapy (CRRT) can be lifesaving . Clinical data, the pediatric risk of mortality (PRISM) scores calculated in the first 24 hours, and pediatric logistic organ dysfunction (PELOD) scores calculated in the last 24 hours before CRRT, were studied . Overall, CRRT was successful in restoring metabolic balance in 72% of patients. PELOD scores before CRRT were lower in survivors ( p  = 0.02). Despite numerous comorbid factors, CRRT can be used effectively in management of metabolic crises. Early intervention with this therapy before occurrence of complications must be targeted.

The impact of continuous renal replacement therapy for metabolic disorders in infants

BACKGROUND

While Continuous Renal Replacement Therapy (CRRT) is a well established treatment modality for patients with acute kidney insufficiency (AKI), it is now also being used for the management of various illnesses such as acute metabolic disorders presenting with hyperammonemia and elevated leucine levels. Herein, we aimed to describe our experience with CRRT in treatment of acute decompensation of 14 patients with a diagnosis of metabolic disorder who has been admitted to our pediatric intensive care unit (PICU) in the last year.

METHODS

Patients who have had life threatening acute metabolic crisis due to various metabolic disorders and were treated with continuous renal replacement therapy (CRRT) were evaluated retrospectively.

RESULTS

Between November 2014 and December 2015, 14 patients were found to have received CRRT for various metabolic disorders in the PICU. Ten patients had hyperammonemia and four patients had elevated leucine levels. Nine patients were male and five were female. The age interval was between 2 days and 18 months, with a mean of 5.5 ± 7.4 months. The weight distribution was between 2.5 and 18 kg, with a mean of 7.3 ± 5.6 kg. Eleven patients received continuous veno-venous hemodiafiltration (CVVHDF), and 3 patients with MSUD received continuous veno-venous hemodialysis (CVVHD). All patients have received high throughput hemodialysis and hemofiltration. The dialyzate rate was set to be minimum 4042 ml/h/1.73 m², and maximum 12,900 ml/h/1.73 m². Hemofiltration was performed with a replacement rate of 40-76 ml/kg/h. The average CRRT duration was 16.6 ± 15.6 h.

CONCLUSIONS

We suggest that CRRT is an efficient method that can be used in hyperammonemia and elevated leucine levels which are metabolic emergencies.

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.

Haemodialysis is an effective treatment in acute metabolic decompensation of maple syrup urine disease

Acute metabolic decompensation in maple syrup urine disease can occur during intercurrent illness and is a medical emergency. A handful of reports in the medical literature describe the use of peritoneal dialysis and haemodialysis as therapeutic inventions. We report the only patient from our centre to have haemodialysis performed in this setting. Combined with dietary BCAA restriction and calorific support, haemodialysis allows rapid reduction in plasma leucine concentrations considerably faster than conservative methods.

Treatment options for lactic acidosis and metabolic crisis in children with mitochondrial disease

The mitochondrial pyruvate oxidation route is a tightly regulated process, which is essential for aerobic cellular energy production. Disruption of this pathway may lead to severe neurometabolic disorders with onset in early childhood. A frequent finding in these patients is acute and chronic lactic acidemia, which is caused by increased conversion of pyruvate via the enzyme lactate dehydrogenase. Under stable clinical conditions, this process may remain well compensated and does not require specific therapy. However, especially in situations with altered energy demands, such as febrile infections or longer periods of fasting, children with mitochondrial disorders have a high risk of metabolic decompensation with exacerbation of hyperlactatemia and severe metabolic acidosis. Unfortunately, no controlled studies regarding therapy of this critical condition are available and clinical outcome is often unfavorable. Therefore, the aim of this review was to formulate expert-based suggestions for treatment of these patients, including dietary recommendations, buffering strategies and specific drug therapy. However, it is important to keep in mind that a specific therapy for the underlying metabolic cause in children with mitochondrial diseases is usually not available and symptomatic therapy especially of severe lactic acidosis has its ethical limitations.