ABOUT THE DISEASE
Arteriovenous malformations (AVMs) are defects of the circulatory system that are generally believed to arise during embryonic or fetal development or soon after birth. They are comprised of snarled tangles of arteries and veins that lead to multiple irregular connections between the arteries and veins.
Arteries carry oxygen-rich blood away from the heart to the body’s cells; veins return oxygen-depleted blood to the lungs and heart. The arteries and veins in an AVM lack this supporting network of smaller blood vessels and capillaries.
The absence of capillaries (small blood vessels that connect arteries to veins and deliver oxygen to cells) creates a short-cut for blood to pass directly from arteries to veins bypassing the surrounding tissues which can potentially cause tissue damage and the death of nerve cells and other cells.
The presence of an AVM disrupts this vital cyclical process. Although AVMs can develop in many different sites, those located in the brain or spinal cord - the two parts of the central nervous system - can have especially widespread effects on the body.
SYMPTOMS
Arteriovenous malformation may not show any signs or symptoms until the AVM ruptures, resulting in bleeding in the brain (hemorrhage). Some of the symptoms may include:
- • Seizures
- • Headache or pain in one area of the head
- • Muscle weakness or numbness in one part of the body
- • Severe headache
- • Weakness, numbness or paralysis
- • Vision loss
- • Difficulty speaking
- • Confusion or inability to understand others
- • Severe unsteadiness
- • Sudden, severe back pain
Symptoms may begin at any age but usually emerge between ages 10 and 40. Brain AVMs can damage brain tissue over time. The effects slowly build up and often cause symptoms in early adulthood. The pregnant women may, sometimes, have worsened symptoms due to changes in blood volume and blood pressure.
CAUSES
AVMs are rare. The cause is not known. Most often AVMs are congenital, but they can appear sporadically. In some cases, the AVM may be inherited while they seem to develop during pregnancy or soon after birth. Doctors use imaging tests to detect them.
DIAGNOSIS
- Clinical Evaluation
- Imaging Studies
• Computed tomography (CT) scan
• Magnetic resonance imaging (MRI)
• Cerebral angiography
• Superselective angiography
TREATMENT METHODS
• Medication is used to treat the symptoms caused by AVM, such as headaches or seizures.
• Surgery, endovascular therapy, and radiosurgery can be used alone or in combination to treat an AVM.
• Endovascular embolization is often performed before surgery to reduce the AVM size and risk of operative bleeding.
• Surgery is the most common treatment for brain AVMs. There are three different surgical options for treating AVMs: Surgical removal (resection); Stereotactic radiosurgery (SRS); Endovascular embolization.
• Radiosurgery or embolization may be used after surgery to treat any remaining portions of the AVM.
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