Brain aneurysm and arteriovenous malformation (AVM) care

A brain aneurysm is a bulge in an artery in the brain. It is caused by a weak area in the blood vessel’s wall. A ruptured brain aneurysm is an aneurysm that breaks open and bleeds. This is a medical emergency and requires treatment right away. 

Sometimes a brain aneurysm that hasn’t ruptured has no symptoms and is discovered by chance. An unruptured aneurysm should be evaluated carefully to determine if it should be treated. The risk of treatment is weighed against the likelihood of the aneurysm bleeding. Sometimes observation alone is recommended. 

An AVM is an abnormal connection between the arteries and veins in the brain. These usually form before birth. Without the normal blood vessels to handle blood flow under pressure, AVMs can start to bleed. The bleeding causes a blood clot in the brain, which can lead to death or disability.

Abut 5 percent of people have a brain aneurysm, but only a small number cause symptoms or rupture. 

Risk factors include:

• Age (most occur in people over 40)
• Drug use, like cocaine
• Family history of brain aneurysms
• Gender (women are at higher risk)
• Heavy alcohol use
• High blood pressure
• Medical problems like polycystic kidney disease
• Race (people of color are at higher risk)
• Smoking

Brain AVMs occur in less than 1 percent of people. The cause is unknown. They generally are not passed down from one generation to the next.

Diagnosis. Getting an accurate, early diagnosis of a brain aneurysm is critical, but most people with this condition have no symptoms until the aneurysm bleeds. Similarly, most people with AVM do not have symptoms until the AVM ruptures and bleeds.

Occasionally, people may experience symptoms without a rupture or bleeding. This occurs when the aneurysm or AVM presses on the brain or nerves and causes symptoms like headache, muscle weakness, numbness or vision problems. These symptoms are similar to other medical problems, so it’s important to work with your doctor to get an accurate diagnosis.   

Symptoms of a ruptured aneurysm or AVM may include: 

• Severe, sudden headache, described as "the worst headache of my life"
• Neck stiffness
• Sensitivity to light
• Nausea and vomiting
• Loss of consciousness
• Seizures

When this bleeding occurs, most people realize that something is wrong and go to a hospital emergency room. 

• Usually patients need a combination of tests for diagnosis and treatment.
• Computed tomography (CT) scan
• MRI
• Cerebral angiogram
• MRA and CTA
• Lumbar puncture

Treatment. The purpose of aneurysm or AVM treatment is to prevent rebleeding. Your treatment will depend on a number of factors, including your general health and age. Our team of neurosurgeons and interventional neuroradiologists will make recommendations based on your unique needs.

There are two main ways to treat these conditions:

Interventional neuroradiology. These procedures are done in a radiology suite  using general anesthesia. An interventional neuroradiologist inserts a thin tube called a catheter to an artery in the groin. Using medical imaging to see inside your body, the doctor guides the catheter to the aneurysm or AVM in the brain.

• To treat an aneurysm, most often the doctor will thread small coils through the catheter into the aneurysm. These coils fill the aneurysm and help prevent rebleeding.
• To treat an AVM, a special type of glue is used to stop blood flow to the AVM, preventing rebleeding.

Surgery. These procedures are done in an operating room using general anesthesia. A neurosurgeon opens the skull and locates the aneurysm or AVM.

• To treat an aneurysm, the neurosurgeon closes it off using a small metal clip. The prevents it from filling with blood and rebleeding.
• To treat an AVM, the neurosurgeon finds and removes it. This prevents it from recurring and rebleeding.