Cerebral arteriovenous fistula

What Is a Cerebral Arteriovenous Fistula? A cerebral arteriovenous fistula (AVF) is an abnormal direct connection between an artery and a vein in the brain. How Normal Blood Flow Works In a healthy circulatory system: Blood flows from arteries → capillaries → veins Capillaries slow blood flow so oxygen and nutrients can be delivered to brain tissue Veins then carry blood back to the heart What Happens in an AVF In a cerebral AVF: Blood bypasses the capillaries Blood flows directly from an artery into a vein This causes high-pressure arterial blood to enter veins that are not designed to handle it Over time, this abnormal circulation can: Reduce oxygen delivery to brain tissue Increase pressure inside veins Raise the risk of bleeding and neurological damage Cerebral AVFs may be congenital (present at birth) or acquired later in life. Symptoms of a Cerebral Arteriovenous Fistula Symptoms vary depending on the size, location, and blood flow of the AVF. Some people have no symptoms initially, while others develop serious complications. Common symptoms include: Hemorrhagic stroke due to bleeding in the brain Sudden severe headache Weakness or numbness Difficulty speaking or moving Seizures Pulsatile tinnitus (a rhythmic “whooshing” sound in the ear) Audible bruit (a sound caused by turbulent blood flow) Neck or back pain Neurological deficits depending on the affected brain area Symptoms can worsen suddenly if bleeding occurs, which is a medical emergency. Causes of Cerebral Arteriovenous Fistulas Cerebral AVFs can develop for several reasons: Congenital Causes Abnormal blood vessel development during fetal growth Present at birth, though symptoms may appear later Acquired Causes Trauma (e.g., head injury, gunshot or stab wounds) Surgical or medical procedures involving blood vessels Vascular conditions, such as aneurysms or other malformations Spontaneous formation, especially in older adults Note: AVFs created surgically for dialysis are intentional and occur outside the brain. Cerebral AVFs are abnormal and potentially dangerous. Complications and Related Conditions If left untreated, a cerebral AVF can lead to serious complications: Brain Bleeding (Intracranial Hemorrhage) Veins exposed to high arterial pressure may rupture Can cause stroke, brain damage, coma or death Seizures Caused by irritation of brain tissue from abnormal blood flow or bleeding Heart Strain and Heart Failure Large AVFs force the heart to pump harder Over time, this can lead to high-output heart failure Blood Clots Turbulent blood flow increases clot formation Can result in deep vein thrombosis (DVT) or pulmonary embolism