Successful Management of Refractory Intracranial Hypertension from Acute Hyperammonemic Encephalopathy in a Woman with Ornithine Transcarbamylase Deficiency

Ornithine transcarbamylase deficiency (OTCD) is the most common of the urea cycle disorders and results in an accumulation of ammonia and its metabolites. Excess ammonia in the brain is metabolized to glutamine, which increases intracellular osmolarity and contributes to cytotoxic edema. We report a case of a woman heterozygous for OTCD who developed acute hyperammonemic encephalopathy and increased intracranial pressure (ICP). Despite hemodialysis, protein restriction, and administration of pharmacologic nitrogen scavengers, she developed progressive cerebral edema and increased ICP that was refractory to maximal medical management. She underwent a bifrontal decompressive craniectomy resulting in resolution of her intracranial hypertension. Aggressive multimodality management of the patient coupled with bifrontal decompressive hemicraniectomy was a life-saving measure, offering the patient a reasonable outcome. At 6 month follow-up she had moderate disability on the Glasgow Outcome Score associated with cognitive difficulties.