Cerebral aneurysm

Berry aneurysm

• Most common type of cerebral aneurysms

• Have a round, saccular shape

• Typically occur at the junctions of vessels in the circle of Willis (the most commonly involved junction is the between anterior communicating artery and anterior cerebral artery)

• Account for approx. 80% of cases of nontraumatic subarachnoid hemorrhage

• Risk factors [5][6]

  • History of congenital conditions: autosomal-dominant polycystic kidney disease, Ehlers-Danlos syndrome, Marfan syndrome, aortic coarctation

  • Hypertension

  • Smoking

  • African-American race

  • Advanced age

  • Hyperlipidemia

  • Excessive alcohol consumption

  • Family history of aneurysms

  • Estrogen deficiency

• Dilation of the entire circumference of the artery

• Most frequently occur in the vertebrobasilar system

• Associated with connective tissue diseases and atherosclerosis

• Mushroom-shaped dilations of infected vessel walls

• Caused by septic emboli (mostly due to bacterial endocarditis)

• Occur at small, peripheral segments of cerebral vessels and often involve the middle cerebral artery.

• Comprise < 1% of all intracranial aneurysms

• Most commonly occur in the supraclinoid ICA and the anterior cerebral artery

• Have a high risk of rupture

• Associated with hypertension and diabetes.

• Affect small lenticulostriate vessels in the basal ganglia and thalamus.

• Their rupture is the most common cause of intracerebral hemorrhage.

• Usually asymptomatic

• The mass effect of the saccular aneurysms depends on the affected vessel.

  • Anterior communicating artery: bitemporal hemianopia; visual acuity defects (CN II compression at the optic chiasm)

  • Posterior communicating artery: mydriasis (CN III parasympathetic fibers compression); ptosis and ophthalmoplegia in severe compression

• See clinical features of ruptured cerebral aneurysms in the “Clinical features” section in the article on “Subarachnoid hemorrhage.”

• Angiography: determines location, size, and morphology of aneurysm (with the exception of Charcot-Bouchard aneurysms, which cannot be detected on angiography)

• See “Subarachnoid hemorrhage” for workup of suspected aneurysmal subarachnoid hemorrhage.

• Unruptured intracranial aneurysms

  • Conservative management includes maintaining normal blood pressure, cessation of smoking, and imaging follow-up.

  • Surgical clipping or endovascular coiling can be considered for patients with life expectancy of > 10 years in the following cases:

    • Large (> 5 mm) or increasing during follow-up aneurysm

    • Location in the posterior circulation or communicating arteries

    • History of subarachnoid hemorrhage

• Ruptured aneurysms: See “Subarachnoid hemorrhage.”