I. Categories
  1. Saccular aka "berry"
    1. Form at areas of weakness in arterial walls, typically bifurcations
    2. Most common type
  2. Fusiform
    1. Have circumferential arterial dilation
    2. Often associated with atherosclerosis
  3. Mycotic
    1. Associated with infection

II. Clinical features and epidemiology
  1. 30% of patients with intracranial aneurysms have more than one
  2. Can be associated with autosomal-dominant polycystic kidney disease (5-40% of patients with ADPKD have an intracranial aneurysm)
  3. Most common presentation is subarachnoid hemorrhage due to rupture.  Risk factors for rupture:
    1. Size
    2. Location in posterior circulation'Hypertension
    3. Use of tobacco or cocaine
    4. Excessive alcohol intake
    5. [Possible] aneurysms associated with familial syndromes
  4. Prior to rupture, may cause headache, facial pain, or cranial nerve palsies
  5. MR angiography is generally the preferred diagnostic test
III. Management
  1. Clipping-Traditional, requires craniotomy, high-risk
  2. Endovascular coils-Less invasive, lower incidence of perioperative death or stroke than clippingm, but recurrence rate is up to 34%
  3. Flow-diversion treatment
    1. Can be uased alone or in combination with endovascular coiling
    2. Involves insertion of one or more porous stents to bridge aneurysm
    3. Two kinds: "silk flow diverter" and "pipeline embolization device" (PED)
    4. May have higher complication rate than endovascular coils
    5. Typically treated with dual antiplatelet therapy after procedure to prevent thrombosis from the stent

(Sources include Core Content Review of Family Medicine, 2012)