Q28.0: Arteriovenous malformation of precerebral vessels

Arteriovenous malformation (AVM) of precerebral vessels is a complex and delicate condition found in the blood vessels of the brain. It is characterized by a snarled tangle of malfunctioning blood vessels and arteries. Normally, there is a network of small vessels that connect arteries and veins. However, in the case of this condition, these connections are not formed correctly. As a result, arteries end up connecting directly to veins, bypassing the network of smaller vessels. This disrupts normal blood flow and pressure, and can result in the vessels becoming swollen and brittle, thereby increasing the risk of rupture and causing bleeding within the brain. Common symptoms include headaches, seizures, or neurological problems like muscle weakness, visual disturbances, or difficulties with speech or movement. While detectable at any age, most people with this condition are born with it, often asymptomatic until an event such as a bleed occurs. The exact cause of AVMs is still unknown, but it is not believed to be hereditary or caused by environmental factors.