A brain aneurysm is a potentially serious medical condition that can remain undetected for years but may become life-threatening if it ruptures.
Defined as a bulge or ballooning in a blood vessel in the brain, a brain aneurysm—also known as an intracranial aneurysm—typically forms when blood flow puts pressure on a weakened area of a vessel wall. One of the most common types resembles a small berry hanging from a stem.
What happens when an aneurysm ruptures
While many brain aneurysms are small and do not cause symptoms, a rupture can lead to bleeding in the brain, resulting in a hemorrhagic stroke. In most cases, this bleeding occurs in the space between the brain and the surrounding membranes, a condition known as subarachnoid hemorrhage.
A ruptured aneurysm requires immediate medical attention, as it can rapidly become fatal.
Types of brain aneurysms
There are three main types of brain aneurysms:
- Saccular (berry) aneurysm: The most common form, appearing as a round, blood-filled sac attached to an artery.
- Fusiform aneurysm: Causes the entire artery wall to bulge.
- Mycotic aneurysm: Develops as a result of an infection that weakens the artery wall.
Symptoms to watch for
Most unruptured aneurysms do not cause symptoms and are often discovered incidentally during imaging tests. However, larger aneurysms may press on surrounding brain tissue or nerves, leading to noticeable signs.
Symptoms of a ruptured aneurysm
The most critical warning sign is a sudden, extremely severe headache, often described as the worst headache of a person’s life.
Other symptoms may include:
- Nausea and vomiting
- Stiff neck
- Blurred or double vision
- Sensitivity to light
- Seizures
- Loss of consciousness
- Confusion
Warning signs before rupture
In some cases, a small leak may occur before a full rupture. This can cause a severe headache that lasts for days or even weeks.
Symptoms of a non-ruptured aneurysm
If an aneurysm grows large without rupturing, it may cause:
- Pain above or behind one eye
- Dilated pupil
- Vision changes or double vision
- Numbness on one side of the face
- Seizures
