Arteriovenous Malformations

An arteriovenous malformations, or AVM for short is a group of blood vessels that is abnormally connected to one another in such a way that arteries connect directly to veins. This causes them to harbor high blood flow pressures, which if high enough, could lead to major bleeding inside the brain. This is why AVMs are a dangerous cause of hemorrhagic stroke.

AVMs are typically present at birth, although their size can change over time. Most people don't find out they have an AVM for years until they develop symptoms such as headaches or seizures. Some people discover they are harboring an AVM after they have suffered a stroke

Other causes of serious strokes:
Aneurysms
Dural Sinus Thrombosis
Carotid Dissection