Acute hyperammonemic encephalopathy secondary to ornithine transcarbamylase deficiency in a child: findings in diagnostic imaging

A four-year-old girl presented with disorientation, drowsiness, anisocoria, tetraparesis and sialorrhea.She had shown significant behavioral changes over the previous six months.Computed tomography revealed bilateral involvement of the frontotemporoparietal and insular cortices, deep and subcortical white matter, confirmed by magnetic resonance imaging, which also showed signs of water diffusion restriction, hyposignal in T1-weighted sequence and no gadolinium enhancement (Figure).A prominent lactate peak was observed in spectroscopy.Urea cycle disorder was suspected after serum urea level was found to be 11 times higher than normal, which was confirmed after a genetic test was positive for heterozygous ornithine transcarbamylase deficiency 1,2,3,4,5 .