Signs and symptoms of dural arteriovenous fistula

A Dural Arteriovenous Fistula (DAVF) is an abnormal connection between an artery and a vein in the tough covering over the brain or spine (the dura). It is a rare, but serious condition.

Not everyone with a Dural Arteriovenous Fistula will experience symptoms, and symptoms can vary based on the location and characteristics of the DAVF. The symptoms may develop gradually and subtly or can become suddenly apparent. If you experience any of these symptoms, especially the severe ones, it’s important to seek immediate medical help.

Why do DAVF cause symptoms?

Normally, blood flows from arteries to capillaries, then into veins. Arteries carry blood with a high amount of pressure from the heart, whereas veins carry blood back to the heart at a lower pressure. The capillaries are small, thin blood vessels in between, which act as a kind of ‘buffer’ system that slows down the flow of blood and allows for the exchange of nutrients and waste products between your blood and your body’s cells.

When a DAVF is present there is an abnormal direct connection between the high-pressure arteries and the low-pressure veins, bypassing the capillaries. This abnormal connection can cause high-pressure blood to flow directly into the veins, which are not designed to handle such high pressure. This increased pressure can dilate and even rupture the veins and small vessels around the DAVF, causing bleeding in or around the brain.

In addition, the high-pressure blood flow can cause the blood in the veins to flow in the wrong direction, a condition called venous reflux. This venous reflux can lead to the congestion of blood and reduction of blood flow to certain areas of the brain or spinal cord. Over time, this can result in tissue damage and loss of function in the affected areas, which can cause symptoms such as weakness, numbness, or even seizures.

In addition, DAVFs can divert blood away from normal brain or spinal tissues. Because of this diversion, these areas may not receive enough oxygen and nutrients, which can cause various neurological symptoms.

The specific symptoms a person experiences can depend on the location of the DAVF and the extent of blood flow disturbance it causes. For example, a DAVF located near the ear may lead to a symptom called pulsatile tinnitus, a whooshing or ringing noise in the ear that corresponds with the heartbeat.

Types of symptoms

Neurological symptoms

  • Headaches: Unusual or chronic headaches that are different from previous headaches in pattern and intensity.
  • Visual disturbances: This can include blurry vision, double vision, or loss of vision.
  • Problems with balance or coordination: Difficulty walking or clumsiness may be noticed.
  • Weakness or numbness: This is typically on one side of the body.

Auditory symptoms

  • Pulsatile tinnitus: This refers to a whooshing sound in the ears, typically in sync with the heartbeat.

Severe symptoms

  • Seizures: This is a sudden, uncontrolled electrical disturbance in the brain. It can cause changes in your behavior, movements or feelings, and in levels of consciousness. There are several types of seizures, but a typical, large, seizure consists of sudden collapse, loss of consciousness, and convulsions (body shaking rapidly and uncontrollably).

  • Stroke-like symptoms: This can include difficulty speaking, facial drooping, or sudden onset of weakness on one side of the body.