From the Guidelines

Hyperammonemia in a neonate indicates a potentially life-threatening condition that requires immediate medical attention.

Hyperammonemia can be caused by inborn errors of metabolism, such as urea cycle disorders (UCDs) and organic acidaemias 1.
Symptoms of hyperammonemia in neonates include lethargy, loss of appetite, vomiting, hypotonia, and hyperventilation, which can progress to seizures, coma, and death if left untreated 1.
The clinical features of an acute hyperammonaemic episode depend on the age of the patient and the underlying cause of hyperammonaemia 1.

Hyperammonemia is defined as >100 µmol/l (170 µg/dl) in neonates 1.
Treatment of hyperammonemia in neonates may involve non-kidney replacement therapy (NKRT) and kidney replacement therapy (KRT), including peritoneal dialysis (PD), haemodialysis (HD), and continuous kidney replacement therapy (CKRT) 1.
Hybrid therapy, such as CKRT with extracorporeal membrane oxygenation (ECMO) support, may be recommended in certain situations, such as haemodynamic instability or rapidly deteriorating neurological status 1.

The prognosis for neonates with hyperammonemia has improved with current treatments, but prompt identification and treatment are crucial to prevent long-term neurological damage and improve survival 1.
The duration of hyperammonaemic coma prior to the start of dialysis is a major determinant of survival, and patient outcomes are not influenced by the rate of ammonia clearance 1.

From the Research

Hyperammonemia in neonates indicates a serious condition that requires immediate medical attention. The key points to consider are:

Hyperammonemia is defined as a plasma ammonia level above 100 µmol/L in neonates 2
It can be caused by inherited metabolic diseases, as well as acquired disorders such as liver failure, portosystemic shunting, and infections with urea-metabolizing organisms 2
Transient hyperammonemia of the newborn (THAN) is a special type of hyperammonemia that can be diagnosed only after excluding genetic and acquired causes of hyperammonemia 2, 3
Hyperammonemia can lead to life-threatening neuropsychiatric symptoms, including seizures, coma, and cognitive impairment 2, 4
The prognosis for THAN is generally good, but timely identification and treatment are essential to prevent long-term neurological damage 2, 3

The clinical presentation of hyperammonemia in neonates may include:

Treatment and management of hyperammonemia in neonates may involve:

Dialysis, which has been shown to be an effective treatment for hyperammonemia 3, 6
Metabolite scavenger (MS) administration, which can help reduce ammonia levels 6
Increasing the length of stay in the neonatal intensive care unit (NICU) to improve short-term survival 6
Monitoring of peak ammonia levels, with further intervention administered when levels exceed 406.5 µmol/L 6