What is the management for hyperammonemia (elevated ammonia level)?

From the Guidelines

An ammonia level of 94 requires immediate management to prevent neurological complications, and the most effective approach is to initiate treatment with ammonia-scavenging agents as recommended in the consensus guidelines for management of hyperammonaemia in paediatric patients receiving continuous kidney replacement therapy 1.

Management Approach

The management of hyperammonaemia involves several key steps:

• Stop protein intake to reduce ammonia production
• Administer i.v. glucose at an infusion rate of 8–10 mg/kg/min to provide energy and reduce catabolism
• Provide i.v. lipids at a dose of 0.5 g/kg daily, up to 3 g/kg daily, to support energy needs
• Ensure caloric intake of ≥100 kcal/kg daily to prevent catabolism
• Administer i.v. sodium benzoate, sodium phenylacetate, or a combination of both, as recommended in the guidelines, to scaveng ammonia
• Consider i.v. l-arginine hydrochloride, l-carnitine, and vitamins (B12 and biotin) as adjunctive therapy ### Ammonia-Scavenging Agents The use of ammonia-scavenging agents, such as sodium benzoate and sodium phenylacetate, is a critical component of hyperammonaemia management. The recommended dosing for these agents is as follows:
• Sodium benzoate: maximum 12 g daily, given over 90 min as a bolus, then as maintenance over 24 h
• Sodium phenylacetate: given over 90 min as a bolus, then as maintenance over 24 h
• Combination therapy: sodium benzoate and sodium phenylacetate, given over 90–120 min as a bolus, then as maintenance over 24 h ### Monitoring and Adjustments Close monitoring of ammonia levels, mental status, and vital signs is essential to adjust treatment as needed. The goal of treatment is to reduce ammonia levels to <200 μmol/l (341 μg/dl) on at least two consecutive hourly measurements, at which point step-down CKRT can be considered 2. ### Dialysis Considerations In patients with severe encephalopathy or rapidly deteriorating neurological status, dialysis may be necessary to rapidly reduce ammonia levels. The choice of dialysis modality, such as intermittent HD or CKRT, should be made jointly by the pediatric, internal medicine, nephrology, metabolism, and critical care teams, taking into account the patient's diagnosis, overall condition, and trend in serum ammonia levels 3.

From the FDA Drug Label

Sodium phenylacetate and sodium benzoate injection infusion should be started as soon as the diagnosis of hyperammonemia is made. Treatment of hyperammonemia also requires caloric supplementation and restriction of dietary protein. Hemodialysis should be considered in patients with severe hyperammonemia or who are not responsive to sodium phenylacetate and sodium benzoate injection administration

The management of an ammonia level of 94 includes:

• Starting sodium phenylacetate and sodium benzoate injection infusion as soon as possible
• Providing caloric supplementation
• Restricting dietary protein
• Considering hemodialysis if the patient has severe hyperammonemia or is not responsive to sodium phenylacetate and sodium benzoate injection administration [4] [5]

From the Research

Management of Ammonia Level of 94

• The management of ammonia levels, particularly in cases of hyperammonemia, involves various treatments depending on the severity and cause of the condition 6, 7.
• For acute severe hyperammonemia, haemodialysis or haemo(dia)filtration is considered the first-line treatment in adults 6.
• In cases of urea-cycle disorders, the combination of intravenous sodium phenylacetate and sodium benzoate has been shown to lower plasma ammonium levels and improve survival 7.
• Dialysis may also be necessary to control hyperammonemia, especially in neonates and older patients who do not respond to intravenous sodium phenylacetate and sodium benzoate 7.
• Other treatments, such as oral administration of sodium benzoate or phenylacetic acid, may be used to prevent hyperammonemia and decrease plasma and CSF concentrations of arginine in patients with hyperargininemia 8.
• A therapeutic protocol that includes prompt recognition of hyperammonemia, therapy with intravenous sodium benzoate, sodium phenylacetate, and arginine, and nitrogen-free intravenous alimentation may be effective in treating episodic hyperammonemia in children with inborn errors of urea synthesis 9.
• Implementing a protocol for the use of combined sodium benzoate and sodium phenylacetate can improve the management of acute hyperammonemia in pediatric intensive care units 10.