Dural Arteriovenous Fistulas – Symptoms and Causes
Overview
Dural arteriovenous fistulas (dAVFs) are abnormal connections between arteries and veins in the dura mater, the protective covering of the brain and spinal cord. These irregular pathways can cause serious health issues, including brain hemorrhage and other significant symptoms.
This condition is uncommon. It typically affects individuals between 50 and 60 years of age. dAVFs are not generally hereditary, meaning parents with this condition don’t pass an increased risk to their children.
Signs and Symptoms
A dural arteriovenous fistula (dAVF) might cause no symptoms in some people. When symptoms do appear, they fall into two main types: mild or severe. Severe dAVFs have more dangerous symptoms.
Severe symptoms can happen when bleeding occurs in the brain. This bleeding often causes a sudden, intense headache. Other symptoms may vary based on where the bleeding happens and how large it is.
Severe symptoms may include:
- Sharp, sudden headache
- Walking difficulties and falling
- Seizures
- Problems with speech or language
- Pain in the face
- Memory and thinking problems
- Movement issues (slowness, stiffness, shaking)
- Poor coordination
- Tingling or burning sensations
- Muscle weakness
- Lack of motivation
- Failure to develop normally
- Symptoms of increased brain pressure (headaches, nausea, vomiting)
Other dAVF symptoms may affect hearing and vision. People might hear a rhythmic sound in their ear that matches their heartbeat. This is called pulsatile tinnitus.
Vision problems may include:
- Changes in vision
- Protruding eye
- Swelling around the eye
- Eye muscle paralysis
In rare cases, increased pressure in brain blood vessels can lead to thinking and memory problems.
When to Get Medical Help
See your doctor if you have any unusual symptoms that concern you. Don’t wait to seek care if symptoms worry you.
Get emergency medical care right away if you have a seizure or signs of brain bleeding, such as:
- Sudden, severe headache
- Nausea and vomiting
- Weakness or numbness on one side of your body
- Problems speaking or understanding others
- Vision loss
- Seeing double
- Balance problems
These symptoms need immediate attention as they may signal a serious problem that requires quick treatment.
Causes
Most dural arteriovenous fistulas (dAVFs) develop without a clear cause. However, several factors may trigger their formation:
- Head trauma
- Infections
- Previous brain surgery
- Blood clots in deep veins
- Brain tumors
Medical experts generally believe that dAVFs affecting larger brain veins develop when one of the brain’s venous sinuses becomes narrowed or blocked. Venous sinuses are important channels that transport blood from the brain back to the heart.
When these pathways become compromised, the body may form abnormal connections between arteries and veins as an alternative route for blood flow.
Risk Factors
Several factors may increase the chance of developing dural arteriovenous fistulas:
- Blood Clotting Issues: People prone to vein thrombosis (blood clots in veins) face a higher risk.
- Vascular Changes: Alterations in blood clotting can lead to blockages or narrowing of venous sinuses.
Age plays a significant role. Most cases affect those between 50-60 years old. However, dAVFs can develop at any age, including in children.
Some research studies have linked benign tumors in the membranes surrounding the brain and spinal cord to the development of these fistulas.
