Stroke

Medical Author: Benjamin C. Wedro, MD, FAAEM
Medical Editor: William C. Shiel Jr., MD, FACP, FACR

• What is a stroke?
• What causes a stroke?
• What are the risk factors for stroke?
• What is a transient ischemic attack (TIA)?
• What is the impact of strokes?
• What are stroke symptoms?
• What should be done if you suspect you or someone else is having a stroke?
• How is a stroke diagnosed?
• What is the treatment of a stroke?
• What complications can occur after a stroke?
• What can be done to prevent a stroke?
• What is in the future for stroke treatment?
• Stroke At A Glance
• Patient Discussions: Stroke - Symptoms Experienced

Recognizing a Stroke: Three Commands for the Victim Medical Author: Medical Author: Melissa Conrad Stöppler, MD Medical Editor: Jay W. Marks, MD Three commands sometimes used by doctors to begin assessing whether a person may be experiencing a stroke can also be useful for people who are not doctors, according to a study by University of North Carolina researchers. Lay persons can command a potential stroke victim to: Smile Raise both arms Speak a simple sentence The three commands, known as the Cincinnati Prehospital Stroke Scale (CPSS), are used by health professionals as a simple first step in the assessment process for signs of stroke. If a person has trouble with any of these simple commands, emergency services (911) should be called immediately with a description of the situation, noting that you suspect the individual is having a stroke. A stroke results from impaired oxygen delivery to brain cells via the bloodstream. According to the U.S. National Institute of Neurological Disorders and Stroke, the five major signs of stroke are the sudden onset of: Numbness or weakness of the face, arm or leg, especially on one side of the body. The loss of voluntary movement and/or sensation may be complete or partial. There may also be an associated tingling sensation in the affected area. Read the rest of the stroke symptoms » Top Searched Stroke Terms: stroke symptoms, management of stroke, signs of a stroke, heat stroke, TIA stroke, stroke recovery, stroke treatment, stroke causes, mini stroke

What is a stroke?

A stroke, or cerebrovascular accident (CVA), occurs when blood supply to part of the brain is disrupted, causing brain cells to die. When blood flow to the brain is impaired, oxygen and glucose cannot be delivered to the brain. Blood flow can be compromised by a variety of mechanisms.

Blockage of an artery

• Narrowing of the small arteries within the brain can cause a so-called lacunar stroke, (lacune=empty space). Blockage of a single arteriole can affect a tiny area of brain causing that tissue to die (infarct).
  
  
• Hardening of the arteries (atherosclerosis) leading to the brain. There are four major blood vessels that supply the brain with blood. The anterior circulation of the brain that controls most motor, activity, sensation, thought, speech, and emotion is supplied by the carotid arteries. The posterior circulation, which supplies the brainstem and the cerebellum, controlling the automatic parts of brain function and coordination, is supplied by the vertebrobasilar arteries.

If these arteries become narrow as a result of atherosclerosis, plaque or cholesterol, debris can break off and float downstream, clogging the blood supply to a part of the brain. As opposed to lacunar strokes, larger parts of the brain can lose blood supply, and this may produce more symptoms than a lacunar stroke.

• Embolism to the brain from the heart. In situations in which blood clots form within the heart, the potential exists for small clots to break off and travel (embolize) to the arteries in the brain and cause a stroke.

Rupture of an artery (hemorrhage)

• Cerebral hemorrhage (bleeding within the brain substance). The most common reason to have bleeding within the brain is uncontrolled high blood pressure. Other situations include aneurysms that leak or rupture or arteriovenous malformations (AVM) in which there is an abnormal collection of blood vessels that are fragile and can bleed.

What causes a stroke?

Blockage of an artery

The blockage of an artery in the brain by a clot (thrombosis) is the most common cause of a stroke. The part of the brain that is supplied by the clotted blood vessel is then deprived of blood and oxygen. As a result of the deprived blood and oxygen, the cells of that part of the brain die. Typically, a clot forms in a small blood vessel within the brain that has been previously narrowed due to a variety of risk factors including:

• high blood pressure (hypertension),
  
  
• high cholesterol,
  
  
• diabetes, and
  
  
• smoking.

Embolic stroke

Another type of stroke may occur when a blood clot or a piece of atherosclerotic plaque (cholesterol and calcium deposits on the wall of the inside of the heart or artery) breaks loose, travels through open arteries, and lodges in an artery of the brain. When this happens, the flow of oxygen-rich blood to the brain is blocked and a stroke occurs. This type of stroke is referred to as an embolic stroke. For example, a blood clot might originally form in the heart chamber as a result of an irregular heart rhythm, such as occurs in atrial fibrillation. Usually, these clots remain attached to the inner lining of the heart, but occasionally they can break off, travel through the blood stream, form a plug (embolism) in a brain artery, and cause a stroke. An embolism can also originate in a large artery (for example, the carotid artery, a major artery in the neck that supplies blood to the brain) and then travel downstream to clog a small artery within the brain.

Cerebral hemorrhage

A cerebral hemorrhage occurs when a blood vessel in the brain ruptures and bleeds into the surrounding brain tissue. A cerebral hemorrhage (bleeding in the brain) can cause a stroke by depriving blood and oxygen to parts of the brain. Blood is also very irritating to the brain and can cause swelling of brain tissue (cerebral edema). Edema and the accumulation of blood from a cerebral hemorrhage increases pressure within the skull and causes further damage by squeezing the brain against the bony skull.

Subarachnoid hemorrhage

In a subarachnoid hemorrhage, blood accumulates in the space beneath the arachnoid membrane that lines the brain. The blood originates from an abnormal blood vessel that leaks or ruptures. Often this is from an aneurysm (an abnormal ballooning out of the wall of the vessel). Subarachnoid hemorrhages usually cause a sudden, severe headache and stiff neck. If not recognized and treated, major neurological consequences, such as coma, and brain death will occur.

Vasculitis

Another rare cause of stroke is vasculitis, a condition in which the blood vessels become inflamed.

Migraine headache

There appears to be a very slight increased occurrence of stroke in people with migraine headache. The mechanism for migraine or vascular headaches includes narrowing of the brain blood vessels. Some migraine headache episodes can even mimic stroke with loss of function of one side of the body or vision or speech problems. Usually, the symptoms resolve as the headache resolves.

Stroke - Symptoms Experienced

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