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The impact of ammonia levels and dialysis on outcome in 202 patients with neonatal onset urea cycle disorders


Hediger, Nina; Landolt, Markus A; Diez-Fernandez, Carmen; Huemer, Martina; Häberle, Johannes (2018). The impact of ammonia levels and dialysis on outcome in 202 patients with neonatal onset urea cycle disorders. Journal of Inherited Metabolic Disease:Epub ahead of print.

Abstract

Neonatal onset hyperammonemia in patients with urea cycle disorders (UCDs) is still associated with high morbidity and mortality. Current protocols consistently recommend emergency medical and dietary management. In case of increasing or persistent hyperammonemia, with continuous or progressive neurological signs, dialysis is performed, mostly as ultima ratio. It is presently unknown whether the currently defined ammonia threshold (e.g., at 500 μmol/L) to start dialysis is useful to improve clinical outcome. A systematic review of clinical and biochemical data from published neonatal onset UCD patients was performed to identify factors determining clinical outcome and to investigate in which clinical and biochemical setting dialysis was most effective. A total of 202 patients (118 proximal and 84 distal UCDs) described in 90 case reports or case series were included according to predefined inclusion/exclusion criteria. Median age at onset was three days and mean ammonia that triggered start of dialysis was 1199 μmol/L. Seventy-one percent of all patients received any form of dialysis. Total mortality was 25% and only 20% of all patients had a "normal" outcome. In general, patients with higher ammonia levels were more likely to receive dialysis, but this had for most patients no influence on outcome. In conclusion, in severe neonatal onset hyperammonemia, the current practice of dialysis, which effectively clears ammonia, had no impact on outcome. It may be essential for improving outcome to initiate all available treatment options, including dialysis, as early as possible.

Abstract

Neonatal onset hyperammonemia in patients with urea cycle disorders (UCDs) is still associated with high morbidity and mortality. Current protocols consistently recommend emergency medical and dietary management. In case of increasing or persistent hyperammonemia, with continuous or progressive neurological signs, dialysis is performed, mostly as ultima ratio. It is presently unknown whether the currently defined ammonia threshold (e.g., at 500 μmol/L) to start dialysis is useful to improve clinical outcome. A systematic review of clinical and biochemical data from published neonatal onset UCD patients was performed to identify factors determining clinical outcome and to investigate in which clinical and biochemical setting dialysis was most effective. A total of 202 patients (118 proximal and 84 distal UCDs) described in 90 case reports or case series were included according to predefined inclusion/exclusion criteria. Median age at onset was three days and mean ammonia that triggered start of dialysis was 1199 μmol/L. Seventy-one percent of all patients received any form of dialysis. Total mortality was 25% and only 20% of all patients had a "normal" outcome. In general, patients with higher ammonia levels were more likely to receive dialysis, but this had for most patients no influence on outcome. In conclusion, in severe neonatal onset hyperammonemia, the current practice of dialysis, which effectively clears ammonia, had no impact on outcome. It may be essential for improving outcome to initiate all available treatment options, including dialysis, as early as possible.

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Additional indexing

Item Type:Journal Article, refereed, original work
Communities & Collections:04 Faculty of Medicine > University Children's Hospital Zurich > Medical Clinic
06 Faculty of Arts > Institute of Psychology
Dewey Decimal Classification:150 Psychology
Language:English
Date:8 March 2018
Deposited On:19 Mar 2018 13:13
Last Modified:19 Mar 2018 14:42
Publisher:Springer
ISSN:0141-8955
OA Status:Closed
Publisher DOI:https://doi.org/10.1007/s10545-018-0157-4
PubMed ID:29520739

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