cerebral amyloid microangiopathy (Alzheimer type)

Etiology

• Alzheimer's disease
• Down's syndrome
• normal aging

Pathology

• amyloid deposition in:
  • leptomeninges (arachnoid & pia)
    • amyloid within leptomeningeal vessels stops abruptly as vessels enter subcortical white matter
  • arterioles, venules & capillaries of cerebral cortex
    • variable for any given burden of amyloid plaque
    • may occur the brains of elderly patients in the absence of AD or neuritic plaques
  • rarely do vessels within white matter contain amyloid
• ultrastructural pathology
  • amyloid fibrils in abluminal basement membrane of vessels
  • spillover of fibrils into perivascular neuropil (dyshorric angiopathy
• hyaline necrosis surrounding amyloid deposits in vessel wall
  • microvascular hemorrhages may occur)
  • amyloid fibrils consist principally of A4/40

More general terms

• cerebral amyloid angiopathy (CAA)

Additional terms

• A4 amyloid peptide; beta-peptide
• Alzheimer's disease (ADD)
• amyloid (senile, neuritic) plaque