Hyperammonemia in Children With Kidney Replacement Therapy Clinical Practice Guidelines (2020)

In April 2020, the Pediatric Continuous Renal Replacement Therapy Workgroup published their recommendations for the management of hyperammonemia in pediatric patients receiving continuous kidney replacement therapy.^[1]

Medical Therapy for Hyperammonemia

In patients with hyperammonemia, protein intake should be discontinued and plasma ammonia levels should be monitored every 3 hours. Initiate intravenous glucose and lipids to provide adequate calories (≥100 kcal/kg daily). Protein should be gradually reintroduced (by 0.25 g/kg daily, up to 1.5 g/kg daily) within 48 hours after ammonia levels decrease to 136-170 μg/dL.

Non-kidney replacement therapy (NKRT) is generally recommended for patients with serum ammonia levels of >255 μg/dL. Start nitrogen-scavenging agents (such as sodium benzoate and sodium phenylacetate) and urea cycle intermediates (such as L-arginine and L-citrulline).

Intravenous L-carnitine is recommended for patients with organic aciduria but is not necessary for those with urea cycle disorder (UCD). Patients with UCD should receive oral phenylbutyrate.

Vitamin B₁₂ and biotin are both recommended for patients with hyperammonemia.

Kidney Replacement Therapies

For neonates and children, dialysis is indicated if the serum ammonia level is >852 μg/dL or if the level does not decrease after 4 hours of medical management.

Continuous kidney replacement therapy (CKRT), specifically high-dose continuous venovenous hemodialysis, is recommended as the first-line treatment. CKRT should be started in patients with hyperammonemia in the following settings:

• Rapidly deteriorating neurologic status, coma, or cerebral edema with a blood ammonia level of >256 μg/dL.

• Moderate or severe encephalopathy.

• Blood ammonia level of >681 μg/dL that persists despite NKRT medical management.

• Rapid increase in the blood ammonia level to >511 μg/dL within a few hours that cannot be controlled with NKRT.

Note that warming the dialysate is advised to help maintain hemodynamic stability in patients who receive CKRT.

Intermittent hemodialysis (HD) is recommended for patients who require rapid ammonia clearance, such as those with rapidly deteriorating neurologic status, coma, or cerebral edema. HD may also be used as initial therapy in patients with blood ammonia levels of >1703 μg/dL.

Hybrid therapy (HD or CKRT combined with extracorporeal membrane oxygenation) is recommended for neonates, particularly those who are hemodynamically unstable.

Peritoneal dialysis can be used to manage hyperammonemia when other kidney replacement therapies, such as HD and CKRT, are not available. Rigid peritoneal catheters are not recommended because they pose the risk of complications, such as clotting and infections.

For more information, please go to Hyperammonemia.

For more Clinical Practice Guidelines, please go to Guidelines.

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Cite this: Hyperammonemia in Children With Kidney Replacement Therapy Clinical Practice Guidelines (2020) - Medscape - May 29, 2020.