What is a Stroke?
This type of stroke happens when a blood vessel leaks or ruptures in or near the brain. The ruptured vessel stops blood supply for the areas past the leak. Then blood floods the nearby tissues causing pressure and function changes.
- Subarachnoid hemorrhage: This occurs when a blood vessel on the surface of the brain ruptures and bleeds into the space between the brain and skull. The most common cause is a ruptured aneurysm caused by high blood pressure. Other causes are rupture of an AVM (arteriovenous malformation), bleeding from an injury due to a blow to the head or venous or capillary problems.
- Intracerebral hemorrhage: This is bleeding into the tissue deep within the brain. High blood pressure is often the cause of this type of stroke. Injury and rupture due to problem vessels can also be the cause.
This type of stroke occurs when a clot or piece of clot clogs a narrowed blood vessel, cutting off the blood flow to a part of the brain. A brain attack caused by too little blood reaching a part of the brain is called an ischemic stroke.
- Thrombotic stroke: This is caused by a blood clot (thrombus) in an artery going to the brain. The clot blocks blood flow to part of the brain. Blood clots may form in arteries damaged by arteriosclerosis. This type of brain attack accounts for around 60 percent of all strokes.
- Embolic stroke: This type of brain attack accounts for about 20 percent of all strokes. It is caused by a clot that formed somewhere else in the body and traveled to clog a vessel in or leading to the brain.
- Systemic hypo perfusion: This occurs because of a low flow of blood to the brain. It happens when too little blood reaches the brain.