Hemorrhagic Stroke

Hemorrhagic strokes occur when a blood vessel in the brain ruptures and bleeds. When an artery bleeds into the brain, brain cells and tissues are deprived of oxygen and nutrients, causing stroke. In addition, pressure builds up in surrounding tissues and irritation and swelling occurs.  This type of stroke usually affects a large area of the brain, is severe, and carries a high risk of death.

About 20 percent of strokes are caused by hemorrhage. These are divided into two main categories:

• Intracerebral hemorrhage - bleeding from the blood vessels within the brain.

• Subarachnoid hemorrhage - bleeding in the subarachnoid space (the space between the brain and the membranes that cover the brain).

Two types of weakened blood vessels usually cause hemorrhagic stroke: aneurysms and arteriovenous malformations (AVMs). An aneurysm is a ballooning of a weakened region of a blood vessel.  If left untreated, the aneurysm continues to weaken until it ruptures and bleeds into the brain. An arteriovenous malformation is a cluster of abnormally formed blood vessels. Any one of these vessels can rupture, also causing bleeding into the brain and thus resulting in an hemorrhagic stroke.

Intracerebral hemorrhage

Intracerebral hemorrhage occurs when a diseased blood vessel within the brain bursts, allowing blood to leak inside the brain.  Bleeding usually occurs suddenly and rapidly. There are usually no warning signs and bleeding can be severe enough to cause coma or death. Intracerebral hemorrhage usually occurs in selected parts of the brain, including the basal ganglia, cerebellum, brainstem, or cortex. It occurs at all ages and the average age is lower than for ischemic stroke.

The most common cause of intracerebral hemorrhage is high blood pressure. Since high blood pressure by itself often causes no symptoms, many people with intracranial hemorrhage are not aware that they have high blood pressure, or that it needs to be treated. Less common causes of intracerebral hemorrhage include trauma, infections, tumors, blood clotting deficiencies, and abnormalities in blood vessels (such as arteriovenous malformations).

Subarachnoid hemorrhage

Subarachnoid hemorrhage occurs when a blood vessel just outside the brain ruptures. The area of the skull surrounding the brain (the subarachnoid space) rapidly fills with blood. A patient with subarachnoid hemorrhage may have a sudden, severe piercing headache, neck pain, and nausea or vomiting. The sudden buildup of pressure outside the brain may also cause rapid loss of consciousness or death.

Subarachnoid hemorrhage is most often caused by abnormalities of the arteries at the base of the brain, called cerebral aneurysms. At the site of maximum swelling, the blood vessel wall becomes weak and prone to rupture.

Subarachnoid hemorrhage can occur at any age, including teenagers and young adults. It is slightly more common in women than men.