What Causes Arteriovenous Malformations?

Medically Reviewed on 12/28/2022
Causes of Arteriovenous Malformations
The major concern about arteriovenous malformations is that they may result in uncontrolled hemorrhage.

Arteriovenous malformations (AVMs) are caused by the development of unusual connections between arteries and veins, but the exact cause of these connections is unknown. Few studies have reported that changes in genes play an important role in AVMs, but most AVMs are not inherited. Brain injuries may also result in AVMs.

The precise cause of arteriovenous malformations (AVMs) is unknown.

According to research findings, an AVM can develop from the following:

What is an arteriovenous malformation?

Arteriovenous malformations (AVMs) are abnormal connections between the blood vessels. The arteries and veins tangle together and form unusual connections. These unusual connections occur during the development of the fetus before birth.

AVMs mostly occur in the brain and spinal cord, but they can occur anywhere in the body.

Mostly, a person with AVM does not show any symptoms. If the symptoms are not seen till 50 years of age, they are never seen again. Women may have symptoms, especially during pregnancy, and the stress in the vessels may result in a few symptoms. Nearly 12 percent of people show symptoms. The condition is discovered while treating some other health condition or when one of the blood vessels in AVM gets ruptured.

The major concern about an AVM is that it may result in uncontrolled hemorrhage. Less than four percent of people show hemorrhage, and it may be serious, sometimes life-threatening. Only one percent of AVMs may turn out to be a direct cause of death.

What happens when an arteriovenous malformation occurs?

Blood circulation is carried out by the blood vessels. Arteries carry oxygenated blood from the heart to the brain and various body organs, whereas veins carry deoxygenated blood from tissues to the heart. The exchange takes place through the capillaries. This "bridge" of capillaries between your arteries and veins is missing if you have an arteriovenous malformation. The force of blood flow from arteries increases the pressure, and the veins, which have weak walls, cannot handle the stress and may burst and bleed, resulting in various health problems.

What are the symptoms of an arteriovenous malformation?

The symptoms of arteriovenous malformations (AVMs) may depend on the location where they are formed. AVMs may get bigger as the person grows. Usually, AVMs grow in size during pregnancy at puberty or after a head injury.

The following are the signs and symptoms of AVM:

Other signs and symptoms include:

  • Muscle weakness
  • Paralysis in half part of the body
  • Loss of coordination
  • Difficulty completing tasks
  • Speech and language problems
  • Numbness, tingling, or sudden pain 
  • Dizziness
  • Backache
  • Weakness in lower extremities
  • Loss of memory
  • Vision problems
  • Hallucinations
  • Confusion

A type of AVM called vein of Galen causes a few symptoms that appear soon after birth. The Galen's vein is located deep inside the cerebrum.

A defect in Galen's vein may show the following symptoms:

  • Hydrocephalous (fluid accumulation in the brain), which results in brain enlargement
  • Swollen veins in the brain
  • Failure to thrive
  • Seizures
  • Congestive heart failure


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How to diagnose arteriovenous malformation

The following are the common tests that are used to diagnose an arteriovenous malformation:

  • Cerebral angiography: Also known as arteriography, where a contrast dye is injected into the artery. The dye helps locate the malformations of the blood vessels.
  • CT scan: Takes pictures of the head, brain, and spinal cord using X-rays from different angles and also helps show the areas of bleeding.
  • MRI: Uses magnetic and radio waves to take pictures.
  • Magnetic resonance angiography: Helps identify the speed and distance of blood flow during vascular movements.

How is an arteriovenous malformation treated?

The treatment of arteriovenous malformations (AVMs) depends on where the AVM is formed, signs and symptoms, risk of treatment, and overall health.

The following are the ways to treat an AVM:

  • Medications for the management of headaches, back pain, and seizures
  • Surgical treatment, where surgery can remove AVM but poses few risks
  • Stereostatic radiosurgery uses highly intense focused beams to treat AVM
Medically Reviewed on 12/28/2022
Image Source: Getty image