II. Epidemiology: Incidence

  1. Incidental finding in 6% of U.S. population
  2. Family History >1 with aneurysm: 9% of population

III. Risk Factors

  1. General risk factors
    1. Age over 50 years
    2. More common in women
    3. Tobacco Abuse
    4. Cocaine Abuse
    5. Head Trauma
    6. Intracranial neoplasm
    7. Hypertension
    8. Alcohol use
    9. Oral Contraceptive
    10. Hyperlipidemia
  2. Inherited conditions
    1. Polycystic Kidney Disease (10-15% have aneurysms)
    2. Type IV Ehlers-Danlos Syndrome
    3. Pseudoxanthoma elasticum
    4. Hereditary Hemorrhagic Telangiectasia
    5. Neurofibromatosis Type I
    6. Alpha-1-Antitrypsin Deficiency
    7. Klinefelter's Syndrome
    8. Tuberous sclerosis
    9. Noonan's Syndrome
    10. Alpha-glucosidase deficiency
    11. Hypertensive conditions (e.g. Pheochromocytoma)
    12. No relationship to Marfan's Syndrome

IV. Types

  1. Saccular Aneurysm (Berry Aneurysm)
    1. Most common Cerebral Aneurysm (90%)
    2. Defect in artery tunica muscularis
    3. Usually occurs at vessel bifurcation
  2. Fusiform Aneurysm
    1. Originates in tortuous arteries
    2. More commonly occurs in vertebrobasilar vessels
  3. Dissecting Aneurysm
    1. Result of cystic medial necrosis or Trauma
    2. Blood follows false lumen

V. Most common sites of aneurysm

VI. Symptoms

VII. Imaging

  1. Intra-arterial digital subtraction angiography
    1. Gold Standard
    2. Permanent neurologic complications in 0.5% cases
  2. MR angiography
  3. CT angiography
  4. Transcranial Doppler Ultrasound

VIII. Complications: Subarachnoid Hemorrhage

  1. Mortality: 50% for ruptured aneurysm
  2. Risk of rupture
    1. Aneurysm >9 mm: 1% annual risk
    2. Aneurysm <10 mm
      1. Prior Subarachnoid Hemorrhage: 0.5% annual risk
      2. No prior Subarachnoid Hemorrhage: 0.05% annual risk
        1. Recent study suggests 0.1% annual risk if <7 mm
        2. (2003) Lancet 362:103-10 [PubMed]

IX. Management: Observation

  1. Periodic imaging with MR Angiogram or CT Angiogram
  2. Indicated when lesions do not meet criteria for neurosurgery
    1. Lesion <3 mm
    2. Lesion 3-7 mm and no high risk criteria (e.g. Posterior Circulation)
    3. Age over 70 years old
  3. Approach
    1. Observed small aneurysms should NOT be considered "time bombs" (rupture risk is low)
    2. Most patients may participate in regular vigorous Exercise without restriction

X. Management: Neurosurgery

  1. Indications
    1. Anterior Circulation aneurysm 7 mm or larger (typically if under age 70 years)
    2. Posterior Circulation aneurysm 3-7 mm or larger (higher risk of rupture)
  2. Open repair via craniotomy
    1. Mortality: 2.6%
    2. Morbidity: 10.9% (decreased neurologic function)
  3. Endovascular treatment (Guglielmi detachable coil)
    1. New procedure with unclear efficacy (ISAT Trial did not evaluate unruptured aneurysm)
    2. Coiling has become the predominant procedure (based on ISAT Trial)

XI. Prevention

  1. Screening asymptomatic patients is not recommended
  2. Screening patients with significant risk factors
    1. May be indicated in high risk cases
    2. Example: Two or more family members with aneurysm
    3. Avoid screening children (delay screening until adult)

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Related Studies

Ontology: Berry Aneurysm (C0005136)

Concepts Disease or Syndrome (T047) , Anatomical Abnormality (T190)
MSH D002532
SnomedCT 125236003, 277196008
English Aneurysms, Berry, Berry Aneurysms, Aneurysm, Berry, berry aneurysms, berry aneurysm, Berry aneurysm, Berry aneurysm (disorder), Berry aneurysm (morphologic abnormality), Berry aneurysm - disorder, Berry Aneurysm
German Beerenaneurysma, Berry-Aneurysma, Aneurysma sacciforme, Beerenförmiges Aneurysma, Sackförmiges Aneurysma
Italian Aneurisma sacciforme, Aneurisma di Berry
Portuguese Aneurisma cerebral sacular, Aneurisma em Amora
Spanish Aneurisma en frambuesa, Aneurisma Sacciforme, aneurisma en frambuesa (anomalía morfológica), aneurisma en frambuesa (trastorno), aneurisma en frambuesa
Japanese 小嚢状動脈瘤, ショウノウジョウドウミャクリュウ
Czech Vakovité aneurysma
French Anévrisme en forme de baie, Anévrysme en forme de baie, Anévrisme ampullaire, Anévrysme ampullaire
Hungarian Bogyó aneurysma
Norwegian Berry aneurysm
Dutch Aneurysma sacciforme, Berry-aneurysma

Ontology: Intracranial Aneurysm (C0007766)

Definition (NCI) A congenital or acquired aneurysm within the cranium.
Definition (MSH) Abnormal outpouching in the wall of intracranial blood vessels. Most common are the saccular (berry) aneurysms located at branch points in CIRCLE OF WILLIS at the base of the brain. Vessel rupture results in SUBARACHNOID HEMORRHAGE or INTRACRANIAL HEMORRHAGES. Giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the OCULOMOTOR NERVE. (From Adams et al., Principles of Neurology, 6th ed, p841)
Concepts Disease or Syndrome (T047)
MSH D002532
SnomedCT 128609009, 42994005
English Aneurysms, Intracranial, Intracranial Aneurysm, Intracranial Aneurysms, Aneurysm, Intracranial, Aneurysm intracranial, Intracranial Aneurysm [Disease/Finding], intracranial aneurysm, aneurysms intracranial, cranial aneurysm, intracranial aneurysms, Intracranial aneurysms, Intracranial aneurysm, Intracranial aneurysm (disorder), Intracranial aneurysm, NOS
German Aneurysma intrakraniell, intrakranielles Aneurysma, Aneurysma, intrakranielles, Intrakranielles Aneurysma
Portuguese Aneurisma intracraniano, Aneurismo intra-craniano, Aneurisma Intracraniano
Swedish Hjärnaneurysm
Czech intrakraniální aneurysma, Aneurysma intrakraniální, Intrakraniální aneurysma
Finnish Kallonsisäinen aneurysma
Japanese 頭蓋内動脈瘤, 動脈瘤-脳, 巨大脳動脈瘤, 真菌性動脈瘤-頭蓋内, 脳動脈瘤-真菌性, 動脈瘤-頭蓋内, 真菌性脳動脈瘤, 頭蓋内真菌性動脈瘤, 脳動脈動脈瘤, 巨大頭蓋内動脈瘤, 脳動脈瘤, トウガイナイドウミャクリュウ
French Anévrisme d'une artère intracrânienne, Anévrysme d'une artère intracrânienne, Anévrysme intracrânien, Anévrisme intracrânien, Anévrisme intra-crânien, Anévrysme intra-crânien
Polish Tętniak śródczaszkowy, Tętniak wewnątrzczaszkowy
Hungarian Intracranialis aneurysma
Norwegian Intrakranialt aneurisme, Aneurisme, intrakranialt
Spanish aneurisma intracraneal (trastorno), aneurisma intracraneal, Aneurisma intracraneal, Aneurisma Intracraneal
Dutch intracraniaal aneurysma, Aneurysma, intracranieel, Intracranieel, aneurysma
Italian Aneurisma intracranico

Ontology: Cerebral Aneurysm (C0917996)

Definition (NCI) A balloon type pouch or bulge in the wall of a cerebral blood vessel.
Definition (CSP) congenital or acquired abnormal outpouching of an intracranial blood vessel wall; saccular (berry) aneurysms are the most common variant, and tend to form at arterial branch points near the base of the brain; rupture results in subarachnoid hemorrhage or intracranial hemorrhages; giant aneurysms (>2.5 cm in diameter) may compress adjacent structures, including the oculomotor nerve.
Concepts Disease or Syndrome (T047)
MSH D002532
ICD10 I67.1
SnomedCT 266316009, 155409000, 128609009
English Aneurysm, Cerebral, Aneurysms, Cerebral, Cerebral Aneurysms, Aneurysm cerebral, Cerebral aneurysm NOS, aneurysms cerebral, cerebral aneurysm, aneurysm cerebral, cerebral aneurysms, Aneurysm-cer.non rupt., Cerebral aneurysm-non ruptured, Cerebral aneurysm, Cerebral Aneurysm
Dutch cerebraal aneurysma, Aneurysma, cerebraal, Cerebraal aneurysma
German Aneurysma zerebral, Zerebrales Aneurysma, Aneurysma, zerebrales
Portuguese Aneurisma cerebral, Aneurisma Cerebral
Spanish Aneurisma cerebral, Aneurisma Cerebral, aneurisma cerebral
Japanese 脳動脈瘤, ノウドウミャクリュウ
French Anévrysme cérébral, Anévrismes cérébraux, Anévrysmes cérébraux, Anévrisme cérébral
Czech Mozkové aneurysma, cerebrální aneurysma
Hungarian Agyi aneurysma
Italian Aneurisma cerebrale
Norwegian Cerebralt aneurisme