Ischemic stroke

Ischemic stroke occurs when a blood vessel carrying blood to the brain is blocked by a blood clot. This causes blood not to reach the brain. High blood pressure is the most important risk factor for this type of stroke. Ischemic strokes account for about 87% of all strokes. An ischemic stroke can occur in two ways.

Embolic Stroke

In an embolic stroke, a blood clot or plaque fragment forms somewhere in the body (usually the heart) and travels to the brain. Once in the brain, the clot travels to a blood vessel small enough to block its passage. The clot lodges there, blocking the blood vessel and causing a stroke. About 15% of embolic strokes occur in people with atrial fibrillation (Afib). The medical word for this type of blood clot is embolus.

Thrombotic Stroke

A thrombotic stroke is caused by a blood clot that forms inside one of the arteries supplying blood to the brain.  This type of stroke is usually seen in people with high cholesterol levels and atherosclerosis. The medical word for a clot that forms on a blood-vessel deposit is thrombus.

Two types of blood clots can cause thrombotic stroke: large vessel thrombosis and small vessel disease.  

Large Vessel Thrombosis

The most common form of thrombotic stroke (large vessel thrombosis) occurs in the brain’s larger arteries. In most cases it is caused by long-term atherosclerosis in combination with rapid blood clot formation. High cholesterol is a common risk factor for this type of stroke.

Small Vessel Disease

Another form of thrombotic stroke happens when blood flow is blocked to a very small arterial vessel (small vessel disease or lacunar infarction). Little is known about the causes of this type of stroke, but it is closely linked to high blood pressure.

Learn more about Strokes using this link:

http://www.stroke.org/understand-stroke/what-stroke/ischemic-stroke

Hemorrhagic stroke

There are two types of stroke, hemorrhagic and ischemic. Hemorrhagic strokes are less common, in fact only 15 percent of all strokes are hemorrhagic, but they are responsible for about 40 percent of all stroke deaths.

A hemorrhagic stroke is either a brain aneurism burst or a weakened blood vessel leak. Blood spills into or around the brain and creates swelling and pressure, damaging cells and tissue in the brain. There are two types of hemorrhagic stroke called intracerebal and subarachnoid

Intracerebral Hemorrhage
The most common hemorrhagic stroke happens when a blood vessel inside the brain bursts and leaks blood into surrounding brain tissue (intracerebal hemorrhage). The bleeding causes brain cells to die and the affected part of the brain stops working correctly. High blood pressure and aging blood vessels are the most common causes of this type of stroke.

Sometimes intracerebral hemorrhagic stroke can be caused by an arteriovenous malformation (AVM). AVM is a genetic condition of abnormal connection between arteries and veins and most often occurs in the brain or spine. If AVM occurs in the brain, vessels can break and bleed into the brain.  The cause of AVM is unclear but once diagnosed it can be treated successfully.

Subarachnoid Hemorrhage

This type of stroke involves bleeding in the area between the brain and the tissue covering the brain, known as the subarachnoid space. This type of stroke is most often caused by a burst aneurism. Other causes include:

• AVM
• Bleeding disorders
• Head injury
• Blood thinners

To learn more about Hemorrhagic strokes use this link: http://www.stroke.org/understand-stroke/what-stroke/hemorrhagic-stroke