Fatal new onset metabolic encephalopathy in a 14 year old boy

Hyperammonaemia may occur in association with a variety of disorders, including liver diseases, Reye's syndrome, portacaval shunts, valproate-induced toxicity, lung transplantation, and urea cycle disorders. We present an unusual case, of a 14 year old boy with a fatal late presentation of a urea cycle disorder. To prevent brain damage and death secondary to hyperammonaemia, cerebral oedema and increased intracranial pressure, a urea cycle disorder should be considered a diagnostic possibility in any patient of any age including adults with occult encephalopathy.