Dural Arteriovenous Fistulas

Dural arteriovenous fistulas (dAVFs) are unusual connections between arteries and veins. These connections are found in the tough membrane that covers the brain and spinal cord, called the dura mater. These abnormal connections, called arteriovenous fistulas, can cause bleeding in the brain or other serious problems.

Dural AVFs are uncommon. They typically develop between the ages of 50 and 60. They're not usually inherited, meaning a child isn't more likely to get one if a parent has one.

While some dAVFs have clear causes, most don't. One theory is that dAVFs involving large brain veins happen when a vein in the brain, called a venous sinus, gets narrower or blocked. These venous sinuses are like channels that carry blood from the brain back to the heart. When a sinus is blocked or narrowed, blood flow can become abnormal, and this abnormal flow can form the dAVF.

Treating a dAVF usually involves procedures to stop the abnormal blood flow. These procedures might include an endovascular technique (using thin tubes and tools to block the connection) or stereotactic radiosurgery (using targeted radiation beams to shrink the dAVF). In some cases, surgery to directly disconnect or remove the abnormal connection may be necessary.

Some people with dural arteriovenous fistulas (dAVFs) don't experience any symptoms. However, when symptoms do appear, they can be either mild or serious. A serious dAVF (often called an "aggressive" dAVF) causes more noticeable and potentially dangerous problems.

These problems can stem from bleeding inside the brain (intracerebral hemorrhage). This bleeding often starts with a sudden, intense headache. The other symptoms depend on precisely where and how much bleeding occurred. The bleeding can also affect other parts of the brain, leading to a range of potential problems.

Serious dAVF symptoms can also arise from non-bleeding neurological problems (nonhemorrhagic neurological deficits, or NHNDs). These might include things like seizures, or changes in how someone thinks or remembers. These symptoms usually develop gradually over days or weeks. They are often directly linked to the part of the brain that's affected.

Examples of serious dAVF symptoms include:

• Sudden, severe headache: This is a key warning sign.
• Problems with walking and balance: This could cause falls.
• Seizures: A sudden electrical disturbance in the brain.
• Trouble speaking or understanding language.
• Facial pain.
• Dementia: A loss of mental abilities.
• Parkinsonism: Slowed movement, stiffness, and tremors.
• Problems with coordination: Difficulty with tasks that require precise movements.
• Numbness or tingling: A burning or prickling sensation.
• Weakness: Loss of strength in parts of the body.
• Apathy: A lack of interest in things.
• Failure to thrive: Not gaining weight or experiencing normal development.
• Increased pressure symptoms: Headaches, nausea, and vomiting are all signs of increased pressure within the skull.

Less serious symptoms can also occur. These might include:

• Hearing problems: Sometimes people with dAVFs hear a rhythmic sound in their ear that matches their heartbeat (pulsatile tinnitus).
• Vision problems: This can range from changes in vision to eye bulging, swelling, or paralysis of eye muscles.

While some cases of increased pressure in the brain blood vessels can rarely lead to dementia, it's important to remember that many of these symptoms can be caused by other conditions.

It's crucial to see a doctor if you have any unusual or concerning symptoms. See a doctor immediately if you experience a seizure or symptoms that might indicate a brain hemorrhage, such as:

• Sudden, severe headache
• Nausea and vomiting
• Weakness or numbness on one side of the body
• Trouble speaking or understanding speech
• Loss of vision
• Double vision
• Problems with balance

Don't hesitate to seek medical attention if you have any worries about your health.

See your doctor if you have any unusual or concerning symptoms.

Get immediate medical attention if you have a seizure or signs of a brain bleed. This includes:

• A sudden, very bad headache: This might be a sign of something serious.
• Feeling sick to your stomach (nausea): Nausea can be a symptom of many things, including a brain bleed.
• Throwing up (vomiting): Vomiting, especially with other symptoms, could indicate a serious problem.
• Weakness or numbness on one side of your body: This is a significant symptom that needs immediate evaluation.
• Trouble speaking or understanding what others are saying: If you're having problems with communication, seek help right away.
• Loss of vision: Sudden vision loss can be a serious issue.
• Double vision: Seeing double can be a symptom of a brain bleed.
• Problems with balance: If you're having trouble keeping your balance, it could be a sign of a problem.

If you experience any of these symptoms, don't delay. Call for emergency medical help right away.

Many cases of dural arteriovenous fistulas (dAVFs) don't have a specific cause. However, some are linked to head injuries, infections, past brain surgeries, blood clots in deep veins, or tumors.

Doctors often believe that dAVFs affecting larger brain veins happen when a part of the brain's venous system gets narrowed or blocked. The venous system is a network of channels within the brain. These channels, called venous sinuses, carry blood from the brain back to the heart.

Dural arteriovenous fistulas (dAVFs) are problems where blood vessels in the membranes around the brain and spinal cord connect improperly. This can happen when blood clots form in the veins (vein thrombosis). These clots can sometimes change how the veins function, potentially leading to blockages or narrowings.

While dAVFs most commonly affect people between 50 and 60 years old, they can happen at any age, including in children.

Research suggests a possible link between dAVFs and certain non-cancerous (benign) growths in the membranes surrounding the brain and spinal cord. These growths, sometimes called tumors, might be related to the development of a dAVF.

A person might need an MRI (magnetic resonance imaging) if they have symptoms of a dural arteriovenous fistula (dAVF). This is a problem where blood vessels in the brain are connected abnormally.

MRI scans: An MRI can show the shape and location of the dAVF, and it can even detect very small bleeds. The scan can help figure out how the abnormal blood vessels are affecting the flow of blood in the brain.

Angiography: A more precise test for diagnosing a dAVF is called angiography. It uses a thin tube (catheter) to take detailed pictures of the blood vessels in the brain. This test is very important because it helps doctors:

• Pinpoint the dAVF: It shows exactly where and how many abnormal connections are present.
• See the blood vessels: It provides a clear picture of the blood vessels that supply blood to the brain (carotid arteries) and the connections between these vessels and the tough membrane covering the brain (dura).
• Understand the fistula's structure: It reveals the exact layout of the abnormal blood vessels making up the dAVF.
• Check for other health issues: Angiography can sometimes detect problems with other blood vessels in the body, like heart disease.
• Assess blood vessel health: The test can show how much narrowing or blockage is present in the dural sinus (a vein-like structure in the brain).
• See if veins are enlarged: It can determine if any veins affected by the dAVF are enlarged and to what degree.

In short, an MRI can provide a general idea of the problem, but angiography gives the most detailed information needed to diagnose and treat a dAVF.