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- An arteriovenous fistula (AVF) is an abnormal channel between an artery and a vein, causing the blood flow to bypass the capilaries. An AVF can be congenital or acquired (traumatic or iatrogenic).
- When congenital AVF are near the surface of the skin, they appear swollen, reddish blue or purple, and on the face they may be unsightley.
May be associated with high output cardiac failure; ulceration of the overlying skin with pain and infection is not uncommon because of the accompanying venous hypertension; malformations with extensive hemagiomatous changes can be associated with thrombocytopenia and purpura
- common form of congenital fistula is the Klippel-Trenaunay-Weber syndrome with port wine staining, varicose veins, and hypertrophy of the involved extremity
- Dural AVF (DAVF)is defined as an abnormal arterio-venous conectivity lying exclusively in the cerebral or spinal dura.
- Cranial DAVF reside usually in the convexity dura overlying the brain hemisphere or in tentorial dura, but occasionally it can involve the cavernous sinus; the symptoms are usually: pulsatile tinnitus, pulsatile proptosis, chemosis, loss of vision, progressive headache, or sudden neurological deficit secondary to brain hemorrhage ( the most feared complication of a cranial DAVF)
- Spinal DAVF may present with a slowly progressive loss of function ( motor or sensory) in the limbs, bowel, bladder, or erectile dysfunction ( progressive myelopathy)
- cerebral DAVF: CT angiography (arteriogram and venogram), MRI including ( MR angiogram and MR venogram; cerebral angiogram- is the gold -standard
- spinal DAVF: spinal MRI, selective spinal angiography
- Treatment: open surgery or endovascular embolization