Hyperammonemia

Hyperammonemia in pediatric patients, particularly those with urea cycle defects like ornithine transcarbamylase (OTC) deficiency, requires rapid identification and aggressive metabolic management to prevent severe neurological damage. Clinical presentation often mimics sepsis, characterized by somnolence, vomiting, and lethargy, especially following catabolic triggers like infections. Initial management focuses on reversing catabolism through high-glucose intravenous fluids, protein restriction, and the use of nitrogen scavengers such as sodium phenylacetate and sodium benzoate to facilitate ammonia excretion. Arginine supplementation is critical for urea cycle support, while valproic acid and glucocorticoids must be avoided due to their inhibitory effects on urea synthesis and protein catabolism. When pharmacological interventions fail or ammonia levels remain persistently elevated above 350–400 micromoles per liter, hemodialysis provides necessary clearance. Continuous monitoring of ammonia levels and electrolyte balance is essential to guide therapy and mitigate risks like cerebral edema.