Health Encyclopedia

Arteriovenous malformation - cerebral

Definition

A cerebral arteriovenous malformation is a birth defect in which there is an abnormal connection between the arteries and veins in the brain.

Alternative Names

AVM - cerebral

Causes, incidence, and risk factors

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.

Arteriovenous malformations vary in their size and location within the brain.

There are often no symptoms until the AVM ruptures. This results in sudden bleeding in the brain (hemorrhagic stroke). In more than half of patients with AVM, hemorrhage is the first symptom. Depending on the location and the severity of the bleed, the hemorrhage can be very disabling or even deadly.

Symptoms of an AVM rupture are similar to a stroke, and occur because of a lack of blood flow to the brain. Symptoms may also occur when large AVMs press on the brain tissue, which can cause nerve damage and blood flow problems.

Cerebral arteriovenous malformations occur in less than 1% of people. Although the condition is present at birth, symptoms may occur at any age. Hemorrhages occur most often in people aged 15 - 20, but can also occur later in life. Some patients with an AVM also have a cerebral aneurysm.

Symptoms

Headache
- Sudden and severe
- Localized or general
- Resembles migraine headache in some cases
Vomiting that occurs with headache
Vision changes
Seizures
- Partial (focal) seizure
- Generalized tonic-clonic seizure
Muscle weakness, any part of the body
Decreased sensation, any part of the body
Mental status change
- Sleepy, stuporous, lethargic
- Confused, disoriented
- Irritability
Stiff neck

Additional symptoms:

Signs and tests

A complete physical examination and neurologic examination are required.

Tests that may be used to diagnose an AVM include:

Head CT scan
Cerebral angiogram
Cranial MRI
MRA (magnetic resonance angiography)
EEG (electroencephalogram) if symptoms include seizures

Treatment

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

Treatments include open brain surgery, endovascular treatment, and radiosurgery. Some treatment options are used together.

Open brain surgery is removes the malformation through an opening made in the skull. It must be done by a highly skilled vascular neurosurgeon. Possible complications include brain swelling, hemorrhage, stroke, or seizure.

Embolization (endovascular treatment) is the injection of a glue-like substance into the abnormal vessels to stop bleeding into the AVM. This may be an alternative if surgery can not be done.

Stereotactic radiosurgery is another alternative. This procedure delivers radiation directly to the area of the AVM. It is particularly useful for small deep AVMS which are difficult to remove by surgery.

Anti-convulsant medications, such as phenytoin, are usually prescribed if seizures occur.

Expectations (prognosis)

Approximately 10% of cases in which hemorrhage is the first symptom are deadly. Some patients may have permanent seizures and neurological problems.

Complications

Intracerebral hemorrhage
Subarachnoid hemorrhage
Seizures
Permanent neurologic changes such as paralysis or sensory problems
Focal weakness
Numbness of any part of the face/body
Vision changes
Language difficulties
Persistent headache
Hydrocephalus (dilated cavities of the brain - "water on the brain")

Calling your health care provider

Go to the emergency room or call the local emergency number (such as 911) if you have a severe headache, vomiting, seizures, weakness or numbness of parts of the body, or other symptoms of a ruptured arteriovenous malformation.

Review Date:10/16/2006
Reviewed By:J.A. Lee, M.D., Assistant Professor of Surgery, Columbia University Medical Center, New York, NY. Review provided by VeriMed Healthcare Network.

ADAM Quality A.D.A.M., Inc. is accredited by URAC, also known as the American Accreditation HealthCare Commission (www.urac.org). URAC's accreditation program is the first of its kind, requiring compliance with 53 standards of quality and accountability, verified by independent audit. A.D.A.M. is among the first to achieve this important distinction for online health information and services. Learn more about A.D.A.M.'s editorial process. A.D.A.M. is also a founding member of Hi-Ethics (www.hiethics.com) and subscribes to the principles of the Health on the Net Foundation (www.hon.ch).

The Agency for Health Care Administration (Agency) and this website do not claim the information on, or referred to by, this site is error free. This site may include links to websites of other government agencies or private groups. Our Agency and this website do not control such sites and are not responsible for their content. Reference to or links to any other group, product, service, or information does not mean our Agency or this website approves of that group, product, service, or information.

Additionally, while health information provided through this website may be a valuable resource for the public, it is not designed to offer medical advice. Talk with your doctor about medical care questions you may have.