Patholgy:
Brain Biopsy:
- Involves the cortex & overlying meninges, sparing the deeper structures.
Histology:
- Congophilic angiopathy: amyloid in medium & small sized arteries. Dyshoric angiopathy: amyloid leaking from capillaries.
- Media & advantitia infiltration. H&E: eosinophilic acellular amorphous material (media & adventitia). Sometimes double barrel vessels (loss of smooth muscle & preservation of endothelium). Congo red stain: apple green birefringence under polarized light. Secondary changes: microaneurysm, fibrosis, chronic inflammation, surrounding hemosiderin
- Associated perivascular lymphocytic infiltrate may occur, B-cells & T-cells
- Immunohistochemistry: beta-amyloid positive in the arteriolar wall, diffusely
Diagnosis:
Combination of clinical findings (age), MRI findings and pathology if present. The Boston criteria is used.
Findings on investigations:
MRI:
- Hemorrhages: usually lobar, rarely SAH or subdural
- Silent infarcts
- Gradient echo GRE: multiple hemorrhages