Ischemic stroke
Some 80 percent of all strokes are caused by blockages of the blood vessels in the brain. They are called ischemic strokes. Ischemic strokes are also divided into two categories, according to the American Heart Association (AHA). They are:

• Thrombotic - these are the result of two things, the slow narrowing of the arteries as fatty deposits build up and the formation of a clot that then lodges in this narrowed opening. (Read about "Arteriosclerosis & Atherosclerosis") AHA says uncontrolled high cholesterol is a risk factor for this type of stroke. (Read about "Cholesterol")
• Embolic - these happen when a clot forms somewhere else in the body, breaks free and eventually lodges in the brain. For example, a type of arrhythmia called atrial fibrillation affects the heart's ability to pump blood, so it may pool and clot. The clot can travel to the brain. In fact, AHA says about 15 percent of strokes occur in people with atrial fibrillation. (Read about "Arrhythmia")

Thrombolysis is the term used for the breaking up of a clot with drug therapy. Ischemic strokes can be treated with a drug called tPA, according to National Institute of Neurological Disorders and Stroke (NINDS). It dissolves blood clots obstructing blood flow to the brain. The window of opportunity to start treating stroke patients is three hours. To be evaluated and receive treatment however, patients need to get to the hospital within 60 minutes. Potential dangers from the drug include internal bleeding in the brain. Some patients, who are not candidates for tPA, may be helped by a newer procedure that involves the use of a tiny corkscrew-shaped device that can remove the blood clot or clots that are blocking the artery.

After an ischemic stroke, blood thinners, antiplatelet drugs or anticoagulants may be prescribed. If a doctor determines that a stroke has been caused by a blockage of a blood vessel leading to the brain, surgery may be needed too. (Read about "Neurosurgery") In a procedure called carotid endarterectomy, surgeons open up the carotid artery in the neck and scrape out plaque. Surgeons also may open up a clogged carotid artery with a small balloon and insert a small tube called a stent to keep the artery open. (Read about "Angioplasty") Following surgery, drugs that prevent more clots from forming may be prescribed. For some patients, who are considered at high risk of having a stroke, carotid artery surgery may be recommended as a prophylactic measure, to prevent a stroke from occurring. Depending on the severity of the stroke, and on the area of the brain impacted, physical rehabilitation may be necessary. (Read about "Rehabilitation") Again, since treatment and rehabilitation should begin as soon after a stroke as possible, it's essential for everyone to recognize the symptoms of a stroke and get help right away.

Hemorrhagic stroke
According to the American Stroke Association, 20 percent of strokes are hemorrhagic strokes. They happen when a weakened vessel ruptures and bleeds into the surrounding brain. This type of stroke can be caused by a head injury (Read about "Head Injury"), for example, or if an aneurysm (a blood-filled pouch that forms on weak spots in the artery wall) bursts. (Read about "Aneurysms") This type of stroke can also be caused by an arteriovenous malformation (AVM), a congenitally malformed mass of thin-walled blood vessels. (Read about "Vascular Lesions of the Central Nervous System") Subarachnoid hemorrhage refers to bleeding in the space between the surface of the brain and the skull. Intracerebral hemorrhage refers to bleeding that occurs within the brain tissue. A hemorrhagic stroke is very dangerous because the accumulated blood from the burst artery may put pressure on surrounding brain tissue and interfere with how the brain functions.

Treatment for hemorrhagic stroke depends on the cause of the hemorrhage and how much damage was done to the brain. With hemorrhagic stroke, doctors want to clot the blood and stop the bleeding. Medication can be used to do this. FDA says hemorrhagic stroke can also be treated with surgery that removes abnormal blood vessels or places a clip at the base of an aneurysm. Aneurysms may also be treated by using catheters. Surgery can also be used to remove the AVM, if this is the cause of the stroke. If high blood pressure caused the hemorrhagic stroke, medication may be used to bring blood pressure down. Depending on the severity of the stroke, and on the area of the brain impacted, physical rehabilitation may be necessary. Again, since treatment and rehabilitation should begin as soon after a stroke as possible, it's essential for everyone to recognize the symptoms of a stroke and get help right away.

TIA's and "silent" strokes
AANS says many people are unaware of the warning signs of a stroke. This is particularly true in the case of a transient ischemic attack (TIA). A TIA is a temporary situation in which you suddenly experience the symptoms of a stroke, but then the symptoms go away after a few minutes. People often ignore a TIA, thinking the problem has disappeared. This can be a fatal mistake because a TIA is serious warning. In fact, according to AANS, approximately 10 to 15 percent of patients who have TIA's will suffer a stroke within one year of the first attack.

In addition, there is also a "silent stroke." The American Heart Association (AHA) says silent strokes are far more common than once thought. Basically, silent strokes occur when small blood vessels in the brain become blocked or rupture. A silent stroke is not accompanied by the classic warning signs of stroke; in fact, someone experiencing silent strokes may not even be aware of it. But eventually, as blood and oxygen supply to the brain diminishes, cells die. This can lead to problems with memory or concentration. It can also create mood changes and lead to depression. (Read about "Depressive Illnesses")

Because of this, the American Stroke Association says seniors should be monitored more carefully for depression since depression may indicate that a silent stroke has already occurred. (Read about "Depression and Seniors")