What is the emergency treatment protocol for hyperammonemia in adults?

From the Guidelines

The emergency treatment protocol for hyperammonemia in adults focuses on rapidly reducing ammonia levels while addressing the underlying cause, with initial management including stopping protein intake, providing adequate caloric support through intravenous dextrose, and administering nitrogen-scavenging medications such as sodium phenylacetate and sodium benzoate. The most recent and highest quality study 1 recommends the following protocol:

• Stop protein intake
• Provide intravenous glucose at a rate of 8-10 mg/kg/min
• Administer intravenous lipids at a dose of 0.5 g/kg daily, up to 3 g/kg daily
• Use nitrogen-scavenging agents such as sodium benzoate and sodium phenylacetate, with a maximum dose of 12 g daily for sodium benzoate
• Consider L-arginine supplementation to support the urea cycle
• Monitor and correct electrolyte abnormalities, particularly potassium depletion In severe cases, continuous renal replacement therapy or hemodialysis should be initiated promptly, with the choice of modality depending on the patient's condition and available resources 1. It is essential to note that the treatment protocol may vary depending on the underlying cause of hyperammonemia and the patient's individual needs. The use of lactulose or rifaximin to reduce intestinal ammonia production may also be considered, as well as intracranial pressure monitoring and management in patients with cerebral edema 1. Overall, the goal of treatment is to rapidly reduce ammonia levels, prevent further neurological damage, and address the underlying cause of hyperammonemia.

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. Non-protein calories should be supplied principally as glucose (8 to 10 mg/kg/min) with an intravenous fat emulsion added Attempts should be made to maintain a caloric intake of greater than 80 kcal/kg/day. Hemodialysis should be considered in patients with severe hyperammonemia or who are not responsive to Sodium Phenylacetate and Sodium Benzoate Injection administration

The emergency treatment protocol for hyperammonemia in adults includes:

• Initiating Sodium Phenylacetate and Sodium Benzoate Injection as soon as the diagnosis is made
• Providing caloric supplementation with glucose (8 to 10 mg/kg/min) and intravenous fat emulsion
• Restricting dietary protein
• Maintaining a caloric intake of greater than 80 kcal/kg/day
• Considering hemodialysis in severe cases or non-responsive patients 2

From the Research

Emergency Protocol for Hyperammonemia in Adults

The emergency treatment protocol for hyperammonemia in adults involves several key steps:

• Prompt recognition of hyperammonemia and its causes, such as urea-cycle disorders or other non-hepatic causes 3, 4
• Initiation of ammonia-scavenging therapies, including intravenous sodium phenylacetate and sodium benzoate, to lower plasma ammonium levels 3, 5, 6
• Provision of adequate calories to prevent catabolism and administration of intravenous arginine hydrochloride as part of the treatment regimen 3
• Consideration of hemodialysis, especially in neonates and older patients who do not respond to intravenous sodium phenylacetate and sodium benzoate 3, 7, 4
• Monitoring of cerebral glutamine levels using magnetic resonance spectroscopy (MRS) as a non-invasive approach for diagnostic and therapeutic monitoring purposes in adult patients presenting with idiopathic hyperammonemia 5

Key Considerations

• The importance of prompt recognition and treatment of hyperammonemia to prevent life-threatening neurological injury and improve outcomes 3, 4
• The need for careful dosing and administration of ammonia-scavenging therapies to avoid toxicity 7
• The potential benefits of combining different therapies, such as L-carnitine and phenylacetate, to reduce valproate-induced hyperammonemia 6
• The importance of considering non-hepatic causes of hyperammonemia, such as drugs, infection, and inborn errors of metabolism, in the diagnosis and management of hyperammonemia in critically ill patients 4