Rapid resolution of hyperammonemia in neonates using extracorporeal membrane oxygenation as a platform to drive hemodialysis

Recomendaciones de manejo de la hiperamonemia en neonatos

La hiperamonemia se define como el aumento de las concentraciones de amonio en el plasma, de forma aguda o crónica. Frecuentemente, se presenta en diversos tipos de errores innatos del metabolismo, enfermedades que deben diagnosticarse y manejarse de manera inmediata y adecuada, debido a que el retraso en su manejo genera secuelas neurológicas graves y permanentes, así como desenlaces fatales. El objetivo del artículo es aportar herramientas al clínico para la sospecha, el abordaje diagnóstico y el manejo del recién nacido con hiperamonemia primaria, teniendo en cuenta la correlación entre fisiopatología, etiología, aproximación clínica y de laboratorio, así como recomendaciones de manejo farmacológico y no farmacológico.

A glance at transient hyperammonemia of the newborn: Pathophysiology, diagnosis, and treatment: A review

Hyperammonemia is the excessive accumulation of ammonia in the blood, and is usually defined as a plasma level above 100 µmol/L in neonates or above 50 µmol/L in term infants, children, and adolescents. Patients with hyperammonemia usually experience life-threatening neuropsychiatric symptoms, especially newborns. It is routinely caused by inherited metabolic diseases and also by acquired disorders, such as liver failure, portosystemic shunting, gastrointestinal hemorrhage, ureterosigmoidostomy, renal tubular acidosis, hypoxic ischemic encephalopathy, infections with urea-metabolizing organisms, and some drugs. Transient hyperammonemia of the newborn (THAN) is a special type of hyperammonemia acknowledged in the field of metabolic disease as an inwell-defined or well-understood entity, which can be diagnosed only after the exclusion of genetic and acquired causes of hyperammonemia. Although the prognosis for THAN is good, timely identification and treatment are essential. Currently, THAN is underdiagnosed and much less is mentioned for early diagnosis and vigorous treatment. Herein, we present common themes that emerge from the pathogenesis, diagnosis, and management of THAN, based on current evidence. When a newborn presents with sepsis, intracranial hemorrhage, or asphyxia that cannot explain coma and seizures, doctors should always keep this disease in mind.

Successful management of a neonate with OTC deficiency presenting with hyperammonemia and severe cardiac dysfunction with extracorporeal membrane oxygenation support and continuous renal replacement therapy

Ornithine transcarbamylase (OTC) deficiency is an X-linked urea cycle disorder which-in severe form-results in rapid accumulation of ammonia and glutamine with subsequent irreversible brain injury. We present a case of severe left ventricular dysfunction with hyperammonemic crisis caused by OTC deficiency which was managed with veno-arterial extracorporeal membrane oxygenation support combined with continuous renal replacement therapy. Aggressive treatment led to normalization of ammonia and full left ventricular recovery.

ECMO as a Platform for Rapid Ammonia Removal in a Neonate with Multienzyme Urea Cycle Disorder

Since the initial deployment of neonatal extracorporeal membrane oxygenation (ECMO) for respiratory failure, the use of ECMO in this population has diversified. We present a term female infant with carbamoyl phosphate synthetase 1 and partial N-acetylglutamate synthase deficiencies who developed severe hyperammonemia refractory to medical management requiring venoarterial ECMO-driven continuous veno-venous hemodiafiltration for ammonia detoxification. This case report illustrates a subpopulation where neonatal ECMO may improve survival and neurodevelopmental outcomes. To our knowledge, this is the first reported case of a urea cycle defect arising from two proximal enzyme deficiencies. Also, this is one of the few reported patients with UCD associated with peak ammonia levels >2,000 μmol/L who survived to hospital discharge after the successful use of ECMO for ammonia reduction. This case will add to the existing scant literature supporting the use of ECMO as a platform for rapid removal of serum ammonia.

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.