Hemorrhagic stroke

There are two main types of stroke: ischaemic stroke and hemorrhagic stroke. Hemorrhagic strokes account for about 20% of all stroke cases.

A hemorrhagic stroke occurs when a blood vessel in the brain suddenly bleeds. As a result, blood collects in the brain, which causes an increase in pressure inside the skull that damages brain tissue. In addition, contact with blood causes inflammation in brain tissue.

Hemorrhagic stroke is a very dangerous condition. Half of all people who get a hemorrhagic stroke die within one month, and many of those who survive are left with some degree of physical and/or mental impairment.

This page details the types of hemorrhagic stroke and the treatment given. For more information on stroke signs and symptoms, diagnosis, complications and rehabilitation, see our stroke report.

Types

There are two main types of hemorrhagic stroke, defined by whether the bleeding occurs inside or outside the brain - an intracerebral hemorrhage or a subarachnoid hemorrhage.

Intracerebral hemorrhage

An intracerebral hemorrhage (ICH) occurs when a blood vessel ruptures inside the brain. Of all stroke cases, 10-15% are this type. Up to half of all people who suffer an ICH die within a month. Of the survivors, four out of five do not remain functionally independent.

ICH can be caused by trauma (such as a blow to the head) or be a spontaneous event. Most (85%) cases of spontaneous ICH are the result of hypertension and/or cerebral amyloid angiopathy, a condition in which a substance called amyloid builds up within the walls of blood vessels in the brain.

In addition, an ICH can be caused by:

• A brain tumor bleeding;
• An aneurysm, which is an abnormally dilated blood vessel with a weak wall that is prone to bleeding (see below), or;
• An ischaemic stroke that causes a blood vessel to rupture.

Subarachnoid hemorrhage

Subarachnoid hemorrhage (SAH) is a type of stroke that occurs when a blood vessel ruptures in the subarachnoid space - the space between the membranes that envelop the brain. SAH accounts for about 5% of all strokes, or a quarter of all hemorrhagic strokes.

Subarachnoid hemorrhagic stroke occurs in younger people more often than other types of stroke; people in their 50s are most at risk. Half of the people who suffer a subarachnoid hemorrhage will die as a result. Of those who survive, many will not return to normal function.

A prominent symptom of this type of stroke is a sudden, very severe headache.

Types of damage to the blood vessel

Another way to classify hemorrhagic strokes is by the damage caused to the blood vessel - either by aneurysm or by arteriovenous malformation. This is an important distinction for treating the hemorrhage.

Aneurysm

An aneurysm is when a spot in the walls of a blood vessel grows weak. As a result, the blood vessel wall balloons outward, and may leak or rupture, causing bleeding.

 

Arteriovenous malformation

An arteriovenous malformation (AVM) is a tangled mass of blood vessels in an area of the body. AVMs are usually present from birth, and can be found in about one in 200 people.

Normally, arteries carry oxygen-rich blood from the heart into tiny capillaries. Each capillary supplies a small number of tissue cells with blood. Different capillaries then carry oxygen-poor blood away from the cells and into veins, which carry the blood back to the heart and lungs, and the cycle starts again.

In an AVM, the delicate branching process that creates the above circuit is abnormal since a person's fetal development; arteries, veins and capillaries are connected haphazardly to each other. Because of this malformation, vessels that form a part of the AVM can often be weaker and have a higher chance of rupturing over time, especially if blood pressure is high.

Treatment

In treating hemorrhagic stroke, the goal is to stop the bleeding quickly. The medicines given for ischaemic stroke will not help a hemorrhagic stroke and may well worsen the situation.

Immediate treatment comprises medications to:

• Lower the blood pressure;
• Lower pressure in the brain,
• Prevent seizures, which can happen during a hemorrhagic stroke, and;
• Stop blood vessels from abnormally constricting and reducing blood flow to other areas of the brain.

More definitive treatment involves locating the site and the character of the hemorrhage (usually with the help of brain imaging scans) and performing surgical procedures (see below) to stem the bleeding and reduce the pressure on the brain.

Surgical procedures

Clipping

Clipping (or clamping) is a surgical procedure in which a small surgical clip is attached to the base of the aneurysm and stems the flow of blood.

Coil embolization

Coil embolization (also called endovascular embolization) involves inserting a small coil through the artery to the aneurysm to seal it off. It is less invasive than clipping, as it does not require opening the skull.

A more recent procedure known as gluing embolization involves sealing off the aneurysm with a glue-like substance rather than a coil.

Decompressive surgery

When blood overflows inside the skull, the pressure it exerts can damage the brain. A hole is surgically drilled into the skull to relieve the pressure. This is known as a 'burr hole'.

AVM surgery

An AVM is surgically treated either by opening the skull and removing the AVM, or by radiosurgery - under certain conditions, a high-energy beam directed at the AVM can help seal the AVM.

Rehabilitation

After the cause of stroke has been successfully treated, the rehabilitation stage can begin. Its general goals are to restore the person to normal function (if possible) and to prevent complications. The character, length, intensity and outcome of this stage are different for every person.

For more information on stroke rehabilitation, see our stroke page.