Cerebral Aneurysm

Basics

Description

  • Abnormal, localized dilation or outpouching of cerebral artery wall:
    • Occurs in 5–10% of population
  • Rupture of saccular aneurysms account for 5–15% of strokes
  • Of those that rupture:
    • 40% occur at anterior communicating artery (ACA)
    • 30% at internal carotid (IC)
    • 20% in middle cerebral artery (MCA)
    • 5–10% in vertebrobasilar artery (VBA) system

Etiology

  • Asymptomatic in 3.2% of population
  • “Congenital,” saccular, or berry aneurysms most common (90%):
    • Develop at weak points in arterial wall and bifurcations of major cerebral arteries
    • Incidence increases with age
    • Multiple in 20–30%
    • Increased incidence:
      • Polycystic kidney disease
      • Cerebral arteriovenous malformation
      • Type III collagen deficiency
      • Fibromuscular dysplasia
      • Ehlers–Danlos syndrome
      • Marfan syndrome
      • Pseudoxanthoma elasticum
      • Neurofibromatosis
      • Moyamoya syndrome
      • Coarctation of the aorta
      • Tuberous sclerosis
      • Sickle cell disease
      • Osler–Weber–Rendu syndrome
      • α1-antitrypsin deficiency
      • Systemic lupus erythematosus
      • Glucocorticoid remediable hyperaldosteronism
  • Arteriosclerotic, fusiform, or dolichoectatic (7%):
    • More common in peripheral arteries
  • Inflammatory (mycotic):
    • 10% of patients with bacterial endocarditis
  • Traumatic, associated with severe closed head injury
  • Neoplastic, embolized tumor fragments
  • Familial correlation: First-degree relative with history of aneurysm essentially doubles lifetime risk

Pediatric Considerations
  • Although rare in children, more likely to be giant (>25 mm)
  • Occur in the posterior circulation

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