Cerebral arteriovenous malformation

AVM - cerebral

The cause of cerebral arteriovenous malformation (AVM) is unknown. The condition occurs when arteries in the brain connect directly to nearby veins without having the normal vessels (capillaries) between them.

AVMs vary in size and location in the brain.

An AVM rupture occurs because of pressure and damage to blood vessel tissue. This allows blood to leak (hemorrhage) into the brain or surrounding tissues, and reduces blood flow to the brain.

Cerebral AVMs are rare. Although the condition is present at birth, symptoms may occur at any age. Hemorrhages occur most often in people ages 15 to 20. It can also occur later in life. Some people with an AVM also have brain aneurysms.

In about half of people with AVMs, the first symptoms are those of a stroke caused by bleeding in the brain.

Symptoms of an AVM that is bleeding are:

• Confusion
• Ear noise/buzzing (also called pulsatile tinnitus)
• Headache in one or more parts of the head, may seem like a migraine
• Problems walking
• Seizures

Symptoms due to pressure on one area of the brain include:

• Vision problems
• Dizziness
• Muscle weakness in an area of the body or face
• Numbness in an area of the body

A complete physical examination and neurologic examination are needed.

Tests that may be used to diagnose an AVM include:

• Brain angiogram
• Computed tomography (CT) angiogram
• Head MRI
• Electroencephalogram (EEG)
• Head CT scan
• Magnetic resonance angiography (MRA)
• Magnetic resonance veinogram

Finding the best treatment for an AVM that is found on an imaging test but is not causing any symptoms can be difficult. Your doctor will discuss with you:

• The risk that your AVM will break open (rupture). If this happens, there may be permanent brain damage.
• The risk of any brain damage if you have one of the surgical treatments listed below.

Your doctor may discuss different factors that may increase your risk of bleeding, including:

• Current or planned pregnancies
• What the AVM looks like on imaging tests
• Size of the AVM
• Your age
• Your symptoms

A bleeding AVM is a medical emergency. The goal of treatment is to prevent further complications by controlling the bleeding and seizures and, if possible, removing the AVM.

Three surgical treatments are available. Some treatments are used together.

Open brain surgery removes the abnormal connection through an opening made in the skull.

Embolization (endovascular treatment):

• A catheter is guided through a small cut in your groin to an artery and then to the small blood vessels in your brain where the aneurysm is located.
• A glue-like substance is injected into the abnormal vessels to stop blood flow in the AVM and reduce the risk of bleeding. This may be the first choice for some kinds of AVMs, or if surgery cannot be done.

Stereotactic radiosurgery:

• Radiation is aimed directly on the area of the AVM. This causes scarring and shrinkage of the AVM and reduces the risk of bleeding.
• It is particularly useful for small AVMs deep in the brain that are difficult to remove by surgery.

Anticonvulsant medicines are usually prescribed if seizures occur.

1 in 10 people whose first symptom is excessive brain bleeding will die. Some people may have permanent seizures and brain and nervous system problems.

AVMs that do not cause symptoms by the time people reach their late 40s or early 50s are more likely to remain stable and rarely cause symptoms.

Complications may include:

• Brain damage
• Intracerebral hemorrhage
• Language difficulties
• Numbness of any part of the face or body
• Persistent headache
• Seizures
• Subarachnoid hemorrhage
• Vision changes
• Water on the brain (hydrocephalus)
• Weakness in part of the body

Possible complications of open brain surgery include:

• Brain swelling
• Hemorrhage
• Seizure
• Stroke

Go to the emergency room or call the local emergency number (such as 911) if you have:

• Numbness in parts of the body
• Seizures
• Severe headache
• Vomiting
• Weakness
• Other symptoms of a ruptured AVM

Also seek medical attention if you have a first-time seizure, because AVM may be the cause of seizures.