Post-anoxic delayed encephalopathy with leukoencephalopathy and non-hemorrhagic cerebral amyloid angiopathy.

A 74 year-old woman with an early-stage senile dementia developed severe hypertonia and akinetic mutism two weeks after exposure to methane. A CT scan showed a diffuse area of decreased density extending symmetrically into the white matter of both cerebral hemispheres. Neuropathology revealed a senile dementia, Alzheimer's type, with severe non-hemorrhagic cerebral amyloid angiopathy and a diffuse spotty demyelination of the cerebral hemispheres sparing the U fibers, corpus callosum and internal capsules. The close resemblance between Grinker's myelinopathy, secondary to CO exposure or to other non-CO anoxic causes, and the leukoencephalopathy associated with cerebral amyloid angiopathy is emphasized.