Stroke

Hemorrhagic stroke occurs when there is bleeding within the brain. It is less common than ischemic stroke but is often more severe.

There are three main causes for bleeding in the brain (intracerebral hemorrhages). High blood pressure can weaken the arteries so that they eventually rupture and cause bleeding. Blood can become too thin as a result of blood thinning medication (anticoagulants). And as people age, they tend to have abnormal deposits of amyloid protein (amyloid angiopathy) in blood vessels, which can lead to bleeding in the brain.

Bleeding around the brain, known as subarachnoid hemorrhage, most often results from a burst aneurysm. An aneurysm develops on a weakened part of a blood vessel and resembles a pouch. A bursting aneurysm is usually signaled by a sudden, unusual, and severe headache. Some have suggested that it feels like being struck on the back of the head by a baseball bat. Other symptoms associated with a burst aneurysm may include neck stiffness and double vision. Not all aneurysms are dangerous or require surgery, but if an aneurysm ruptures it is quite serious.

The second most common cause of subarachnoid hemorrhages is the rupture of a cluster of abnormal blood vessels in the brain, the arteriovenous malformation.