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What is a stroke?

Stroke, also called brain attack, cerebrovascular accident, or cerebral infarction, is a very serious condition in which the brain is not receiving enough oxygen to function properly. Stroke often results in serious and permanent complications and disability. It is the third leading cause of death in the United States, according to the American Stroke Association. (Source: ASA).

The brain requires a steady supply of oxygen in order to function effectively. Oxygen is supplied to the brain from the blood that flows through arteries. A stroke occurs when an artery that supplies blood to the brain becomes blocked or ruptures and begins to leak. When this occurs, the area of the brain that is not getting enough oxygen-rich blood from that artery is damaged. The injury can become permanent within minutes and results in death of the affected brain tissue. Medically this is called cerebral necrosis. A stroke can also cause a buildup of pressure inside the skull, which can result in permanent injury to the brain.

Stroke is a form of cardiovascular disease. There are two main types of strokes:

  • Hemorrhagic strokeoccurs when an artery in the brain ruptures or leaks blood.

  • Ischemic strokeoccurs when an artery in the brain has been blocked.

The extent of the damage done to the brain during a stroke varies depending on such factors as the type of stroke, the area or areas affected, and how much time passes before the stroke is treated.
A stroke is potentially an immediately life-threatening condition. Immediate emergency treatment best minimizes the risk of death and other serious complications, such as permanent neurological damage, paralysis, and disability.

Seek immediate medical care (call 911) if you, or someone you are with, have one or more symptoms of a stroke, including confusion, disorientation, slurred speech, inability to move a part of the body, or passing out.


What are the symptoms of a stroke?

Symptoms of a stroke can differ depending on the type of stroke, the area or areas affected, how much time passes before the stroke is treated, and individual factors.

In some cases, symptoms of a stroke occur suddenly but they can be mild and vague. These symptoms include:

These symptoms may also be warning symptoms of a condition called a transient ischemic attack (TIA). A TIA is sometimes incorrectly referred to as a small stroke or ministroke. In contrast to a stroke, the effects of a TIA are temporary and generally go away by themselves.
Despite the temporary effects of a TIA, it is important to understand that symptoms of a TIA need immediate medical evaluation and treatment. Symptoms of a TIA generally indicate underlying problems in blood circulation in the brain and can be a warning sign of an upcoming stroke.

Serious symptoms that might indicate a life-threatening condition

Stroke is a potentially life-threatening condition. Seek immediate medical care (call 911)if you, or someone you are with, have any of the following warning signs and symptoms of stroke:

  • Abnormal pupil size or nonreactivity to light

  • Change in level of consciousness or alertness, such as passing out or unresponsiveness

  • Change in mental status or sudden behavior change, such as confusion, delirium, lethargy, hallucinations or delusions

  • Change in vision

  • Difficulty understanding speech

  • Disorientation

  • Drooping of the face

  • Droopy eyelid

  • Garbled or slurred speech or inability to speak

  • Impaired breathing or swallowing

  • Numbness

  • Paralysis or difficulty moving the face, a leg or arm, or entire side of the body

  • Severe weakness


What causes a stroke?

A stroke occurs when an artery that supplies blood to the brain becomes blocked or ruptures and begins to leak. The two main types of stroke are ischemic and hemorrhagic.

The primary causes of ischemic stroke include cerebral embolism and cerebral thrombosis:

  • Cerebral embolismis a clot that forms in a part of the body outside the brain. A cerebral embolism travels through the bloodstream and lodges in an artery that supplies blood to the brain. This blocks blood flow to the brain, resulting in an ischemic stroke.

  • Cerebral thrombosisoccurs due to a buildup of plaque and inflammation in the brain arteries. This is called atherosclerosis. Atherosclerosis narrows the brain arteries and reduces the amount of oxygen-rich blood that reaches the brain tissue, which can lead to symptoms of a transient ischemic attack (TIA), a warning sign of an impending stroke. Arteries narrowed by atherosclerosis are more likely to develop a blood clot (cerebral thrombosis) that completely blocks blood flow to an area of the brain. This is an ischemic stroke.

The second type of stroke, hemorrhagic stroke, is caused by cerebral hemorrhage. A cerebral hemorrhage occurs when an artery in the brain breaks open or leaks blood into the surrounding brain tissue, causing a buildup of pressure and damage to brain tissue. A ruptured brain aneurysm can cause a cerebral hemorrhage and hemorrhagic stroke.

What are the risk factors for stroke?

A number of factors are thought to increase your chances of having a stroke. Risk factors include:

  • African American ancestry

  • Atherosclerosis (buildup of plaque on the walls of the coronary arteries; atherosclerosis is a type of arteriosclerosis)

  • Brain aneurysm (life-threatening bulging and weakening of a brain artery)

  • Diabetes (chronic disease that affects your body’s ability to use sugar for energy)

  • Excessive alcohol consumption

  • Family history of heart disease or stroke

  • Heart disease (cardiovascular disease)

  • High blood pressure (hypertension)

  • Male gender

  • Obesity

  • Postmenopause

  • Sedentary lifestyle

  • Smoking

Reducing your risk of stroke

Not all people who are at risk will have a stroke, but you can reduce your risk of stroke by:

  • Eating a diet that is low in saturated fat and high in fiber, whole grains, fruits and vegetables

  • Maintaining a healthy weight

  • Not drinking alcohol or limiting alcohol intake to one drink per day for women and two drinks per day for men

  • Not smoking

  • Participating in a regular exercise program

  • Seeking regular medical care and following your treatment plan for such conditions as high cholesterol, hypertension, and diabetes


How is a stroke treated?

If diagnosed early, some strokes can be successfully treated before the development of permanent neurological damage and complications, such as paralysis and disability. Stroke treatment plans include a multifaceted approach and are individualized to the type and severity of your stroke, your risk factors, lifestyle, medical history, and other diseases and conditions you have.

Typical treatments for a stroke include medications, hospitalization, supplemental oxygen, intensive monitoring, stabilization of vital signs, and surgical procedures.

General treatments for stroke

  • Intensive monitoring and stabilization of heart rhythm and vital signs. In some cases, this may require CPR and advanced life support measures, such as intubation and mechanical ventilation to support breathing.

  • Monitoring of heart rate and rhythm with an electrocardiogram (known as an EKG or ECG)

  • Monitoring of neurological status

  • Monitoring of pressure inside the brain

  • Supplemental oxygen to increase the amount of oxygen that is delivered to the brain tissue and the rest of the body

  • Treatment of abnormal heart rhythms (cardiac arrhythmias) with medications and possibly cardioversion or electrical defibrillation

Medications used to treat ischemic stroke

Certain medications may be used to treat an ischemic stroke that is caused by a blood clot in a brain artery. These medications are not used to treat a stroke caused by bleeding in the brain (hemorrhagic stroke) because they can increase bleeding and worsen a hemorrhagic stroke. Medications for an ischemic stroke may include:

  • Aspirin, which helps prevent new blood clots (antiplatelet)

  • Heparin, which helps prevent new blood clots (anticoagulant)

  • Thrombolytic (clot-dissolving) drugs, which break up and dissolve the clot that is causing the stroke. Thrombolytic drugs are most effective if given within a few hours of the onset of stroke symptoms.

Surgical treatments for stroke

In some cases, surgery may be performed to treat or prevent a stroke. Surgical procedures may include:

  • Carotid endarterectomy to prevent a stroke or a recurrent stroke caused by narrowing of the brain arteries or a blood clot. This surgery removes the built-up plaque in the brain arteries and improves blood flow to the brain.

  • Surgery to prevent or treat certain types of hemorrhagic stroke caused by a brain aneurysm (weakening or bulging of a brain artery that can rupture or leak blood into the brain)

  • Surgery to reduce dangerously high levels of pressure on the brain tissue caused by a ruptured or leaking brain aneurysm

Other treatments for stroke

Other treatments for stroke often follow emergency measures for stroke to help people regain their strength, avoid complications, and prevent a subsequent stroke. Other treatments include:

  • Palliative care to improve overall quality of life for families and patients with serious diseases

  • Regular follow-up care to help monitor your treatment and progress and to address any problems or complications promptly

  • Rehabilitation and physical therapy to help strengthen the body, reduce complications, increase alertness, reduce fatigue, and improve overall health and functional ability

Complementary treatments

Some complementary treatments may help people to better cope with a stroke and potential complications. These treatments, sometimes referred to as alternative therapies, are used in conjunction with traditional medical treatments. Complementary treatments are not meant to substitute for traditional medical care. Be sure to notify your doctor if you are consuming nutritional supplements or homeopathic (nonprescription) remedies as they may interact with the prescribed medical therapy.

Complementary treatments may include:

  • Acupuncture

  • Massage therapy

  • Nutritional dietary supplements, herbal remedies, tea beverages, and similar products

  • Yoga

What are the possible complications of stroke?

Complications of a stroke can be life threatening. Stroke can also lead to permanent disability. Complications of a stroke can be caused by the stroke itself, such as brain damage, or from long-term immobility and disability. You can help minimize your risk of some complications by following the rehabilitation and stroke recovery plan you and your health care professional design specifically for you. Complications of stroke include:

  • Aspiration

  • Bedsores

  • Blood clots

  • Coma

  • Contractures

  • Dementia

  • Depression

  • Incontinence and urinary tract infection

  • Malnutrition

  • Memory loss

  • Myocardial infarction

  • Muscle wasting and permanent deformities of the arms or legs (contractures) due to deceased mobility of the limbs 

  • Paralysis

  • Permanent difficulties with walking, talking, understanding speech, and movement of the limbs

  • Permanent disability

  • Pneumonia

  • Seizures

Was this helpful?
Medical Reviewer: William C. Lloyd III, MD, FACS
Last Review Date: 2019 Jan 4
  1. NINDS Stroke Information Page. National Institute of Neurological Disorders and Stroke, National Institutes of Health.
  2. About Stroke. American Heart Association.
  3. What is Stroke? National Stroke Association.
  4. Stroke. Merck Manual.
  5. Jauch EC, Saver JL, Adams HP Jr, et al. Guidelines for the early management of patients with acute ischemic stroke: a guideline for healthcare professionals from the American Heart Association/American Stroke Association. Stroke 2013; 44:870.

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