Causes of ischemic stroke
- A blood clot can form in an artery that supplies blood to the brain.
- A blood clot can form in another part of the body (often the heart) and travel through the bloodstream to the brain. For example, clots may form:
Low blood pressure may also cause an ischemic stroke, although this is less common. Low blood pressure results in reduced blood flow to the brain. It may be caused by narrowed or diseased arteries, a heart attack, a large loss of blood, or a severe infection.
Some surgeries (such as endarterectomy) or other procedures (such as carotid artery stenting) that are used to treat narrowed carotid arteries may cause a blood clot to break loose, resulting in a stroke.
Causes of hemorrhagic stroke
A hemorrhagic stroke is caused by bleeding in or around the brain.
- Bleeding inside the brain itself (intracerebral hemorrhage, or ICH) may be a result of long-term high blood pressure or use of blood thinner medicine, such as anticoagulants.
- Bleeding in the space around the brain (subarachnoid hemorrhage, or SAH) may be caused by a ruptured aneurysm or uncontrolled high blood pressure.