Brain Aneurysm (Intracranial Aneurysm)
A brain aneurysm is a balloon-like outpouching that forms because of a weakness in the wall of a brain blood vessel. Most aneurysms cause no symptoms; if one ruptures, it can lead to a life-threatening subarachnoid hemorrhage.
最終更新: 2026-06-06
Definition
An intracranial aneurysm is a localized dilation resulting from structural weakness in the wall of a brain artery. Most are saccular (berry-shaped) and typically occur at vessel branch points, especially around the circle of Willis at the skull base. The risk of rupture varies with size and shape.
Causes and Risk Factors
On a background of structural vessel-wall weakness, hypertension, smoking, advanced age and family history are important risk factors. Polycystic kidney disease and certain connective tissue disorders increase aneurysm frequency. Rupture risk relates to aneurysm size, location, shape and patient factors.
Symptoms
Most unruptured aneurysms are silent and often found incidentally on imaging done for other reasons. Large aneurysms may cause compression symptoms (e.g., drooping eyelid, double vision). At rupture, the hallmark is a sudden, often described as the worst-ever, headache, which may be accompanied by altered consciousness, neck stiffness and vomiting — a medical emergency.
Diagnosis
When acute rupture is suspected, the first study is a non-contrast brain computed tomography (CT); if hemorrhage is not demonstrated, a lumbar puncture may follow. Aneurysm anatomy is evaluated with CT angiography, MR angiography or the gold-standard digital subtraction angiography (DSA).
Treatment
For ruptured aneurysms, the goal is to exclude the aneurysm from the circulation to prevent rebleeding. The two main methods are surgical clipping and endovascular coil embolization; flow-diverting stents are used in some cases. For unruptured aneurysms, the decision to treat or observe is individualized by balancing rupture risk against procedural risk.
Prognosis
In ruptured aneurysm, prognosis is closely related to hemorrhage severity and complications (rebleeding, vasospasm, hydrocephalus); early diagnosis and treatment are important. The course of unruptured aneurysms is highly variable. Outcomes differ by patient and none is guaranteed.
参考文献
- Greenberg MS. Greenberg's Handbook of Neurosurgery. 10th ed. Thieme; 2023:1416-1428.
- Winn HR, ed. Youmans Neurological Surgery. 6th ed. Saunders; 2011:3747-3754.
- Thompson BG, et al. Guidelines for the Management of Unruptured Intracranial Aneurysms. Stroke (AHA/ASA). 2015.
- Molyneux A, et al. International Subarachnoid Aneurysm Trial (ISAT). Lancet. 2002.
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