Too Much of a Good Thing: A Man with Altered Mental Status

Results of an initial evaluation, including liver enzyme and function testing, were normal. Neuroimaging and cerebrospinal fluid studies were also unrevealing. The patient rapidly entered a coma and required intubation. Plasma ammonia level measurement demonstrated severe hyperammonemia (344 μmol/l; reference range, <45 μmol/l). After normalization of the ammonia level with treatments including nitrogen binders and laxatives, the patient underwent metabolic and genetic testing that eventually isolated a mutation in the gene encoding ornithine transcarbamylase (OTC), an enzyme in the urea cycle.