Reversible delayed posthypoxic leukoencephalopathy.

Hypoxic ischemic encephalopathy may cause early deep white matter abnormalities on MR imaging that usually progress to include gray matter and basal ganglia change. Toxic leukoencephalopathy due to heroin inhalation predominantly causes cerebellar and posterior cerebral radiologic change. Both conditions rarely present clinically and radiologically in a delayed manner with subsequent recovery. We report a case of reversible delayed posthypoxic/toxic leukoencephalopathy with no clinical or radiologic evidence of gray matter insult.