Cerebral amyloid angiopathy

Cerebral amyloid angiopathy (CAA) is the cerebrovascular deposition of amyloid-beta. It is common amongst elderly, a cause of spontaneous intracerebral hemorrhage, and an important contributor to age-related cognitive decline (Charidimou et al 2017).

• Epidemiology
  • CAA is prevalent in 20-40% of non-demented, and 50-60% of demented elderly (age range 80-90 years) (Keage et al, 2009)
  • in Alzheimer disease it is prevalent in 82-98% of cases (Jellinger 2002)

• Clinical presentation
  • spontaneous lobar ICH, cognitive impairment, dementia
  • cognitive decline: the independent contribution of CAA is difficult to determine because of the high co-existance of Alzheimer's disease and other age-related pathologies, though it appears to independently contribute to cognitive decline beyond its accompanying pathologies (Charidimou et al 2017).
    • moderate to severe CAA in older community dwelling population was associated with lower perceptual speed and episodic memory (Arvanitakis et al 2011)
  • "amyloid spells", or transient focal neurological episodes (TFNEs), generally associated with SAH or superficial siderosis

• Diagnostics
  • MRI with blood sensitive sequences
    • multiple lobar cerebral microbleeds, cortical superficial siderosis, white matter disease, cortical microinfarcts, MRI-visible perivascular spaces in the centrum semiovale
    • Modified Boston Criteria for Cerebral Amyloid Angiopathy (Linn et al, 2010)
      • Definite CAA - full post-mortem examination demonstrating:
        • lobar, cortical, or cortical-subcortical hemorrhage
        • severe CAA with vasculopathy
        • absence of other diagnostic lesion
      • Probable CAA with supporting pathology - clinical data and pathologic tissue (evacuated hematoma or cortical biopsy) demonstrating:
        • lobar, cortical, or cortical-subcortical hemorrhage (ICH, CMB, or cSS)
        • some degree of CAA in specimen
        • absence of other diagnostic lesion
      • Probable CAA - clinical data and MRI or CT demonstrating:
        • multiple hemorrhages (ICH, CMB) restricted to lobar, cortical, or cortical-subcortical regions (cerebellar hemorrhage allowed), OR single lobar, cortical, or cortical-sbcortical hemorrhage and cSS (focal or disseminated)
        • age 55 or older
        • absence of other causes of hemorrhage
      • Possible CAA - clinical data and MRI or CT demonstrating:
        • single lobar, cortical, or cortical-subcortical ICH, CMB, or cSS (focal or disseminated)
        • age 55 or older
        • absence of other cause of hemorrhage

References

Arvanitakis Z et al. Cerebral amyloid angiopathy pathology and cognitive domains in older persons. Ann Neurol (2011). https://www-ncbi-nlm-nih-gov/pubmed/21387377

Charidimou A, et al. Emerging concepts in sporadic cerebral amyloid angiopathy. Brain. Jul 1;140(7):1829-1850. (2017) https://pubmed.ncbi.nlm.nih.gov/28334869/

Jellinger KA. Alzheimer disease and cerebrovascular pathology: an update. J Neural Transm (Vienna). May;109(5-6):813-36 (2002). https://pubmed-ncbi-nlm-nih-gov/12111471/

Keage HA, et al. Population studies of sporadic cerebral amyloid angiopathy and dementia: a systematic review. BMC Neurol (2009). https://www-ncbi-nlm-nih-gov/19144113

Linn J, et al. Prevalence of superficial siderosis in patients with cerebral amyloid angiopathy. Neurology. 74:1346–1350. (2010). https://www-ncbi-nlm-nih-gov/20421578