What Is a Brain Aneurysm?
A brain aneurysm, also known as a subarachnoid hemorrhage (SAH), is a weak spot in the wall of a blood vessel inside the brain. Think of a weak spot in a balloon and how it feels stretched out and thin. A brain aneurysm is like that.
That area of the blood vessel gets worn out from constant flow of blood and bulges out, almost like a bubble. It can grow to the size of a small berry. There are different types:
Saccular aneurysms are the most common type of brain aneurysm. They bulge out in a dome shape from the main artery. They’re connected to that artery by a narrow “neck.”
Fusiform aneurysms aren’t as common as saccular aneurysms. They don’t pouch out in a dome shape. Instead, they make a widened spot in the blood vessel.
Although brain aneurysms sound alarming, most don’t cause symptoms or health problems. You can enjoy a long life without ever realizing that you have one.
But in rare cases, aneurysms can grow big, leak, or explode. Bleeding in the brain, known as a hemorrhagic stroke, is serious, and you’ll need medical care right away.
Brain Aneurysm Symptoms
The type of symptoms you have from a brain aneurysm depend on whether it ruptures or not.
Ruptured brain aneurysm symptoms
You need emergency care if you suddenly get an intensely painful headache, lose consciousness, or have some of these other symptoms of an aneurysm rupture:
- Intense headache that comes on suddenly
- Loss of consciousness
- Nausea and vomiting
- Loss of balance in things like walking and normal coordination
- Stiff neck
- Dilated pupils
- Sensitivity to light
- Sudden blurred or double vision
- Drooping eyelid
- Confusion or trouble with mental awareness
Although brain aneurysms usually don’t show symptoms, they can press on the brain and nerves as they get bigger.
Unruptured brain aneurysm symptoms
See a doctor at once if you’re having the following symptoms of an unruptured aneurysm:
- Dilated pupils
- Blurred or double vision
- Pain above and behind an eye
- Drooping eyelid
- A hard time speaking
- Weakness and numbness in one side of your face
A sudden and intense headache can also be a sign you have a leaking aneurysm (sentinel bleed). This can be a sign you’ll soon have a full rupture.
Brain Aneurysm Causes
Brain aneurysms usually develop as people age, becoming more common after 40. It’s also possible to have a blood vessel defect at birth.
Women tend to have higher rates of aneurysms than men.
Aneurysms tend to form at the fork of blood vessels, places where they branch off, because those sections tend to be weaker. They are most commonly found at the base of the brain.
Brain Aneurysm Risk Factors
Things in your medical history that can play a role include:
- High blood pressure
- Atherosclerosis, a disease in which fat builds up inside the walls of your arteries (blood vessels that deliver oxygen-rich blood throughout your body)
- Diseases affecting your blood or blood vessels:
- Connective tissue disorders such as Ehlers-Danlos syndrome
- Polycystic kidney disease
- Injury or trauma to your head
- Cancer or tumors in your head and neck
- Abnormalities at birth, such as tangled blood vessels in your brain, abnormally narrow aorta (coarctation of the aorta), or cerebral arteriovenous malformation (brain AVM)
- Family history of brain aneurysms
Brain Aneurysms in Children
Rarely, kids under 18 can have a brain aneurysm. Boys are eight times more likely to get them than girls. Of the few cases in children, about 20% are “giant” aneurysms (larger than 2.5 centimeters).
Aneurysms in kids can come on for no reason. But they’re also sometimes related to:
- Head trauma
- Connective tissue disorders
- Genetic disorders
- Family history
Brain Aneurysm Diagnosis
Several types of scans and tests can be used to figure out whether you have a brain aneurysm. They include:
CT scan: This exam creates images of your brain. You will lie on a table that slides into a CT scanner. A technician will inject contrast dye into one of your veins to make it easier to see the blood flow and spot aneurysms in your brain.
MRI: This exam is similar in that you lie on a table that slides into a scanner. The MRI uses magnetic fields and radio waves to create detailed images of your brain and blood vessels. MRIs and CT scans can detect aneurysms larger than 3 to 5 millimeters.
The following tests are more invasive than CT or MRI scans. But they could give you and your doctors a more complete picture of what’s going on:
Angiogram: This test, considered the most reliable way to detect aneurysms, shows the weak spots in your blood vessels. During the test, you lie on an X-ray table, and you will be given something to numb any pain. Your doctor will insert a small flexible tube through a blood vessel in the leg. They’ll guide that tube, called a catheter, into the blood vessels in your neck that reach the brain. Then they’ll inject a contrast dye into you, and X-rays will be taken that show all the blood vessels in the brain. This gives your doctor a map of your blood vessels, pinpointing the aneurysm.
Cerebrospinal fluid test: Your doctor may order this test if they think an aneurysm may have ruptured.
You’ll be given something to block any pain. A technician will put a needle into you to draw spinal fluid. That fluid is tested to see whether it contains blood, which could mean an aneurysm has ruptured.
Brain Aneurysm Treatment
Ruptured brain aneurysm treatment
You need treatment as soon as possible if you have a ruptured brain aneurysm, because it’s likely that it will bleed again. Treatment involves stopping the blood flow into the aneurysm.
The procedures carry risks. Your doctor will figure out which treatment works best based on your health, and the size, type, and location of the aneurysm.
Surgical clipping: A section of your skull is removed to locate the aneurysm. A metal clip is placed on the opening of the aneurysm to cut off the blood flow. Your skull is then sealed shut.
Endovascular coiling: This doesn’t require surgery that opens the skull. Your doctor will insert a catheter into your groin to reach the affected blood vessel where the aneurysm is located.
The doctor will send tiny platinum coils through the tube and place them inside the aneurysm. The coils conform to the shape of the aneurysm, stopping the blood flow there. This may be safer than surgical clipping, but it has a higher chance of the aneurysm bleeding again.
Flow diverter surgery: This option is for larger brain aneurysms in which neither clipping nor coiling would work. In this procedure, your doctor inserts a stent, usually made of metal mesh, inside the artery. It becomes a wall inside the vessel to divert blood away from the aneurysm.
To help manage symptoms and prevent complications of an aneurysm, your doctor may suggest:
- Pain relievers such as acetaminophen
- Medications called calcium channel blockers that help prevent blood vessels from narrowing
- Treatments to prevent a stroke, such as drugs that raise your blood pressure so blood will flow through narrowed blood vessels, or a procedure called an angioplasty that uses a small balloon to widen blood vessels
- Anti-seizure medication
- Ventricular or lumbar draining catheters to reduce pressure on the brain
- Shunt surgery
- Rehabilitative therapy to help you relearn skills you may have lost from damage to your brain
Unruptured brain aneurysm treatment
Small aneurysms that haven’t ruptured and aren’t causing symptoms may not need treatment. But this depends on your health and the aneurysm. You can talk this all over with your doctors.
If you are living with a brain aneurysm that has not ruptured, lifestyle changes can help lower your chances of having it leak or pop:
Brain Aneurysm Complications
A ruptured brain aneurysm can be life-threatening and lead to: