Dural arteriovenous fistula is an abnormal connection of vessels in the tissues around the brain or spinal cord in which one or more arteries are directly connected to one or more veins or venous spaces called sinuses. Arteries carry blood from the heart to the tissues, and veins take blood back from the tissues to the heart. In a DAVF, there is a direct connection between one or more arteries and veins or sinuses which gives rise to many problems.
Signs and Symptoms
There are two major types of AVFs: dural AVFs and carotid-cavernous fistulas (CCFs). These are acquired lesions, which mean that patients are not born with them, but instead develop them later in life. They can be a result of infection or traumatic injuries, but most develop without any specific precipitating event. Patients with dural AVFs typically present with a rumbling noise in one ear that follows the heartbeat, which is called a bruit.
In the classification of vascular anomalies currently employed, a division is made between vascular tumors and vascular malformations. The first group is characterized by high turnover of endothelium, whereas the latter is characterized by the presence of dysmorphogenesis with no evidence of abnormal epithelial turnover.
All AVMs are present at birth, but they are not always clinically evident. Stimuli during puberty or pregnancy or following minor trauma can precipitate clinical features of the malformation. AVMs occur with equal frequency among males and females.