What are the other Names for this Condition? (Also known as/Synonyms)

• AVM of the Brain
• Brain Arteriovenous Malformation
• Brain AVM

What is Arteriovenous Malformation of the Brain? (Definition/Background Information)

• Arteriovenous Malformation (AVM) of the Brain is the presence of abnormal arteries and veins in the brain that are enlarged and twisted. The condition is rare and is typically manifested in adults between 20-40 years of age
• An Arteriovenous Malformation of the Brain can occur in any part of the brain including in the:
  • Frontal, parietal, temporal, or occipital lobes
  • Cerebellum
  • Brainstem
  • The dura, which is the membrane covering of the brain
  • The spaces in the brain called ventricles; in which the cerebrospinal fluid circulates
• Although rare, AVMs are the most common vascular malformations of brain. It is believed to begin forming in the early developmental stages, when capillaries that connect arteries and veins are missing in parts of the brain, resulting in abnormal connections
• The size of this tangled structure is variable; it can often reach several centimeters in diameter. The symptoms of Arteriovenous Malformation of the Brain include headaches, numbness, weakness, and seizures. However, it is also possible for Brain AVMs to exist without presenting any symptoms
• The risk factors for this condition have not been currently identified. However, having a family history of brain vascular malformations and being a male, may pose some risk for developing this abnormality of the blood vessels
• The exact cause of Arteriovenous Malformations of the Brain is also not known. They may occur owing to abnormal development of blood vessels during gestation, and therefore, may be present at birth. The weakened, abnormal blood vessels can burst, leading to bleeding in the brain. In adults, a dural AVM can develop as a consequence of an injury/accident
• A healthcare professional may perform a physical examination, assess symptoms and evaluate personal and family medical history towards establishing a diagnosis of Brain AVMs. The affected individual is often referred to a specialist, who may conduct imaging studies, such as computed tomography (CT), magnetic resonance imaging (MRI) scans, and cerebral arteriography, to arrive at a final diagnosis
• Some potential complications from the disorder are bleeding in the brain, stroke, loss of vision, numbness, memory problems, difficulties with speech, weakness, rupturing of blood vessels and damage to the brain. Pregnant women with AVMs of the Brain may experience hemorrhaging
• The treatment option is determined by the size and location of the malformations. The affected individual may be prescribed medication for headaches and seizures. The abnormality can be surgically removed, the blood supply to the anomaly stopped with embolization, or radiation may be administered for treating Arteriovenous Malformations of the Brain
• The prognosis of Arteriovenous Malformations of the Brain depends on the size and location of the malformation. There is a possibility that a bleeding can cause permanent injury/paralysis, and be fatal as well. If no complications arise, the outcomes are generally positive

Who gets Arteriovenous Malformation of the Brain? (Age and Sex Distribution)

• Arteriovenous Malformations of the Brain are the most common type of vascular malformations of the brain
• But, the condition is rare and less than 1% of the world population is reportedly affected. Some studies indicate that approximately 1 in every 200-500 individuals may have the disorder
• The disorder can occur at any age; but a peak age of onset is observed in individuals who are between 20-40 years old
• Both genders can be affected, although males are more prone to this type of brain vascular malformations than females
• AVMs can occur in people belonging to all races and ethnic backgrounds and no particular preference is noted

What are the Risk Factors for Arteriovenous Malformation of the Brain? (Predisposing Factors)

The risk factors for Arteriovenous Malformations of the Brain may include:

• Being a male
• Rarely, a family history of the condition

It is important to note that having a risk factor does not mean that one will get the condition. A risk factor increases ones chances of getting a condition compared to an individual without the risk factors. Some risk factors are more important than others.

Also, not having a risk factor does not mean that an individual will not get the condition. It is always important to discuss the effect of risk factors with your healthcare provider.

What are the Causes of Arteriovenous Malformation of the Brain? (Etiology)

The exact cause of Arteriovenous Malformations of the Brain is not known.

• The condition arises owing to malformations in arteries and veins of the brain
• Most cases of AVM are not inherited and a family history is not observed
• A gene mutation leading to AVMs has been suggested, although no strong evidence exists to support this theory
• It is believed that accidents can cause the formation of dural type of Brain AVMs in adults

What are the Signs and Symptoms of Arteriovenous Malformation of the Brain?

The signs and symptoms of Arteriovenous Malformations of the Brain may include the following:

• Hemorrhage or bleeding in the brain (occurs in about half of the affected individuals)
• Seizures (occurs in 20-25% of the affected individuals)
• Headache
• Weakness
• Numbness
• Difficulty with movement (in about 15% of the cases)
• Sight and speech problems (in about 15% of the cases)

In some individuals, the signs and symptoms may be mild or unnoticeable.

How is Arteriovenous Malformation of the Brain Diagnosed?

The diagnosis of Arteriovenous Malformations of the Brain is made through the following exams and tests:

• A thorough physical examination and an assessment of symptoms
• An evaluation of the affected individual’s personal and family medical history
• Cerebral arteriography:
  • This test provides information on the location and characteristics of the feeding arteries and draining veins, as well as blockages
  • A thin tube is threaded up towards the brain and inserted into an artery in the groin; a dye is injected through this thin tube. The dye provides a contrast for X-ray analysis of the affected organ/area
• Computerized tomography (CT) scans of the brain; it may include CT angiogram that may be performed with a dye injection
• Magnetic resonance imaging (MRI) of the brain; it may include MRI angiogram with an injected dye

Many clinical conditions may have similar signs and symptoms. Your healthcare provider may perform additional tests to rule out other clinical conditions to arrive at a definitive diagnosis.

What are the possible Complications of Arteriovenous Malformation of the Brain?

Possible complications of Arteriovenous Malformations of the Brain include:

• Hemorrhage or bleeding in the brain
• Increased risk of recurrent bleeding
• Reduced oxygen supply to the brain tissues which may result in:
  • Stroke
  • Difficulty in speaking
  • Weakness
  • Numbness
  • Loss of vision
  • Unsteadiness, which may be very severe
• Thin or weak blood vessels which may lead to the following:
  • Bulges in the blood vessel wall (aneurysm)
  • Rupture of the blood vessels
• Damage to the brain: Enlargement of the blood vessels may displace or compress the brain (brain tissue moving up against the skull), preventing the free flow of fluids around the brain. Fluid may start to build up in the brain resulting in a condition known as hydrocephalus

How is Arteriovenous Malformation of the Brain Treated?

The treatment options for Arteriovenous Malformations of the Brain may include:

• Medications for seizures and headaches
• Surgical removal of the malformation
• Endovascular embolization: The introduction of small particles to block the flow of blood, with the help of a catheter (introduced in a leg artery)
• Stereotactic radiosurgery: Use of radiation to destroy tangled vessels

How can Arteriovenous Malformation of the Brain be Prevented?

Presently, there are no methods or guidelines available for preventing the formation of Arteriovenous Malformations of the Brain.

What is the Prognosis of Arteriovenous Malformation of the Brain? (Outcomes/Resolutions)

• The prognosis of Arteriovenous Malformations of the Brain is dependent upon the size and location of the condition within the brain
• The outcome is good, if no complications arise. If there are complications, such as bleeding in the brain, it can lead to paralysis and occasionally be fatal

Additional and Relevant Useful Information for Arteriovenous Malformation of the Brain:

• Dandy-Walker malformation (DWM) is a rare, congenital malformation of the brain that includes the cerebellum and the fluid filled spaces around it

The following link may help you find useful additional information on Dandy-Walker malformation:

http://www.dovemed.com/diseases-conditions/dandy-walker-malformation/