Alzheimer's disease, cerebral amyloid angiopathy, and dementia of acute onset.

The coexistence of cerebral amyloid angiopathy (CAA) and Alzheimer's disease (AD) should be considered in the differential diagnosis of cases with acute onset of dementia when other causes have been excluded. We report clinical and neuropathological findings in a 78-year-old man who developed dementia of acute onset with an apparent rapid course three months before his death. Postmortem microscopic examination of the brain revealed senile (neuritic) plaques and neurofibrillary tangles in the hippocampus and cerebral cortex. CAA affected vessels of the neocortex and leptomeninges, most severely in the frontal and parietal areas.