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Arteriovenous malformation and dural arteriovenous fistula are cerebrovascular disorders diagnosed and treated at HonorHealth hospitals.
A cerebral arteriovenous malformation is an abnormal connection that usually forms before birth between arteries and veins in the brain. The cause 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 size and location in the brain. A rupture occurs because of pressure and damage to brain tissue, as well as a lack of blood flow to the brain. Symptoms also can occur when large arteriovenous malformations that have not bled press on the brain tissue.
Arteriovenous malformation occur in less than 1 percent of people. Although the condition is present at birth, symptoms can occur at any age. Hemorrhages occur most often in individuals between the ages 15 to 20, but also can occur later in life. Some patients with an arteriovenous malformation also have cerebral aneurysms.
There often are no symptoms until the arteriovenous malformation ruptures. This results in sudden bleeding in the brain (hemorrhagic stroke). In more than half of patients with arteriovenous malformation, hemorrhage is the first symptom. Symptoms of arteriovenous malformation hemorrhage are the same as those of other intracerebral hemorrhage.
Physical and neurological exams are needed, but they could be completely normal. Your HonorHealth neurologist might use some of these tests to diagnose an arteriovenous malformation:
A bleeding arteriovenous malformation is a medical emergency. The treatment goal is to prevent further complications by controlling the bleeding and seizures and, if possible, removing the arteriovenous malformation.
Treatments (some are used together) include:
A dural arteriovenous fistula is a site of abnormal connectivity between arteries and veins, where the abnormal connection, or fistula, lies in the covering of the brain or spinal cord known as the dura.
Unlike arteriovenous malformations, which are thought to be present from birth, cranial dural arteriovenous fistulas often develop later in life after blockage or thrombosis of a cranial dural venous sinus. When a venous sinus blocks off, the brain can try to compensate by moving venous blood across other collateral pathways. In this process, however, a fistula might form, representing an abnormal collateral pathway to drain blood away from the brain. This could occur due to chronic central nervous system infection, brain trauma or a patient with a tendency to experience thrombosis.
Dural arteriovenous fistula can occur:
Cranial dural arteriovenous fistula are more commonly diagnosed in women over 40, while spinal dural arteriovenous fistula are more commonly diagnosed in men over 40.
Depending on the location of the fistula, symptoms of dural arteriovenous fistula in the head may be a whooshing sound heard by the patient, or abnormal eye bulging and pulsation, and impairment of vision and/or eye movement. Isolated but persistent headaches, or symptoms of a brain hemorrhage including a sudden severe headache, neurological impairment and/or collapse are also common.
Symptoms of a spinal dural arteriovenous fistula may be slow but progressive loss of function in the limbs (more often the legs than the arms), bowel and bladder dysfunction including incontinence, and progressive erectile dysfunction in males.
Any of the above symptoms and signs may lead to investigation by your specialist. Unfortunately, in the case of spinal dural arteriovenous fistula, the diagnosis may be missed or delayed because such lesions occur so rarely, and when they do occur, their symptoms and signs may be mistaken for disk disease or spinal cord inflammation.
For a cranial dural arteriovenous fistula, regular CT scanning is not very helpful in diagnosing a fistula, but it might show a hemorrhage from a fistula. CT angiography, which is CT arteriography plus CT venography, is helpful in defining a cranial fistula; so are MRI techniques. However, the standard for detection and characterization of a dural arteriovenous fistula is cerebral angiography.
For a spinal dural arteriovenous fistula, the standard is selective spinal angiography. In this process, a catheter is used to inject multiple spinal segmental arteries arising from the aorta, one by one, until the fistula is found and characterized.
The two main ways of treating a dural arteriovenous fistula are through: