U.S. flag

An official website of the United States government

NCBI Bookshelf. A service of the National Library of Medicine, National Institutes of Health.

InformedHealth.org [Internet]. Cologne, Germany: Institute for Quality and Efficiency in Health Care (IQWiG); 2006-.

Cover of InformedHealth.org

InformedHealth.org [Internet].

Show details

Stroke: Overview

Created: ; Last Update: July 13, 2017; Next update: 2020.


The signs of a stroke include a sudden and severe headache, paralysis, or difficulty speaking. These problems are caused when part of the brain doesn’t get enough blood.

The symptoms mainly depend on which part of the brain is affected.

A stroke is a medical emergency that requires immediate treatment. The medical term for a stroke is apoplexy.


Common signs of a stroke include sudden weakness, numbness and signs of paralysis, speech problems, trouble seeing, dizziness, difficulty walking, and a severe headache. Usually, only one side of the body is affected, making it impossible to move the right arm and/or right leg, for example. Nausea and vomiting are also possible symptoms.


In most cases strokes are caused by a blood clot that is blocking a blood vessel in the brain. These clots can form in the brain itself, for example because of changes in the artery wall caused by infection. However, they are more likely to form in another part of the body and be carried into the brain in the bloodstream, where they then block a blood vessel. A stroke that is caused by a blocked blood vessel is referred to as an ischemic stroke.

Bleeding (hemorrhage) in the brain is the second, less common cause. This occurs if, for instance, a blood vessel ruptures and blood leaks into the brain tissue.

In both cases, one part of the brain is no longer supplied with enough oxygen. The sooner the treatment is started and the oxygen supply is restored, the better the chances are of minimizing damage to the brain.

Risk factors

It is very uncommon for blood clots to develop in the blood vessels of healthy people. But certain conditions and genetic factors can increase the risk of a stroke. These include high blood pressure and persistent atrial fibrillation.

Typical signs of a stroke that then go away on their own after a few hours may be signs of a transient ischemic attack (TIA). This happens when a blood clot forms but then breaks up again before the brain is damaged more severely. People who have had a transient ischemic attack (TIA) are more likely to have a stroke.

Prevalence and outlook

About 1 out of 1,000 people have a stroke in their lifetime. The risk increases with age: About 20 out of 1,000 people aged over 85 are affected.

Most people survive strokes. But they can lead to paralysis in certain parts of the body or problems with various abilities, such as speaking.

Symptoms such as paralysis often get better over time, but they can also be permanent. Psychological problems like depression are therefore not uncommon.

And people who have had a stroke are also at greater risk of having another. About 40 out of 100 people who survive a stroke have another stroke within ten years.

The risk is particularly high within the first six months. Other cardiovascular diseases, such as heart attacks, are also more likely to occur in people who have had a stroke.


Strokes are medical emergencies. If you think you or somebody else might be having a stroke you should call for an ambulance immediately (112 in Germany and many other countries; 911 in the U.S.). Do not wait to see if the symptoms go away.

After the paramedics have examined the patient, he or she will be taken to the hospital – if possible, one that specializes in strokes, as long as it isn’t too far away. There, comprehensive testing can be started immediately, so that the cause of the symptoms can be determined and treatment can be started soon afterwards. The tests typically include computed tomography (CT) or magnetic resonance imaging (MRI).


Whether or not particular preventive measures against a stroke are worthwhile will depend on whether the person has any other conditions and risk factors.

If someone has already had a transient ischemic attack or a stroke, doctors will usually suggest preventive measures after carefully examining them.

People with high blood pressure can reduce their risk of a stroke by taking blood-pressure-lowering medication. Anticoagulants are an option for people who are at greater risk of blood clots forming – for example, if they have atrial fibrillation.

Sometimes a wire mesh stent (blood vessel support) is recommended in order to keep a blood vessel in the brain free of clots. But studies have shown that this procedure more often causes bleeding in the brain, resulting in a greater risk of further strokes than would be the case without a stent.


Acute treatment aims to save a person's life and minimize damage as much as possible. The type of treatment will mainly depend on whether the stroke was caused by a blood clot or a hemorrhage.

If it was caused by a blood clot, the doctors generally try to break it up as quickly as possible using medication or a catheter. Brain hemorrhages have to be stopped quickly, sometimes by operating.

Further treatment and observation then depends on the severity of the stroke, the type of effects that the stroke has had, and the results of further examinations.


Most people find it very important to regain their mobility, muscle strength, speech, and independence after having a stroke. Restoring emotional balance is also key.

There are various rehabilitation programs with different contents. The main elements of rehabilitation include speech therapy, physiotherapy and fitness training to try to minimize any physical disabilities and learn to manage with them. Occupational therapy involves learning how to successfully cope with challenges in daily life as well as possible, despite the limitations.

Everyday life

It's normal for people to feel sad and depressed after a stroke. Depending on how severe the stroke was, it can have an enormous impact on a person's life.

People who used to live independently and now have to rely on others for help have to come to terms with the effects of the stroke first – both the psychological consequences as well as the practical challenges in everyday situations.

Rehabilitation treatment can help people to regain some of their independence after a stroke. Most people and their families manage to gradually adjust to the changes in their lives as well as possible.

However, some people develop depression as a result of a stroke, and need professional help for it. If the depression lasts for a long time it can affect their overall health. These kinds of depression often go unnoticed, or sadness and feeling down are sometimes considered to be a normal reaction and no steps are taken to treat it.

It can be difficult to know if a person who has had a stroke is suffering from normal sadness or depression. It's important that stroke patients and their families receive the support that they need to prevent depression, or are offered help if depression has already set in.

Further information

A lot of support is available for people who have had a stroke, as well as for their families. For instance, there are special information centers and self-help groups that can provide patients and their families with help concerning nursing care, finances and psychosocial issues.

Lots of cities and municipalities have nursing care information centers that can be consulted free of charge.

Family members can also take part in nursing care courses to learn basic care techniques, among other things.

The available services will depend on the center and can’t always be found immediately. We have put together a list of places that you can contact to find out where you can get help in your local area (in Germany only).


  • Brereton L, Carroll C, Barnston S. Interventions for adult family carers of people who have had a stroke: a systematic review. Clin Rehabil 2007; 21(10): 867-84. [PubMed: 17981846]
  • Forster A, Brown L, Smith J, House A, Knapp P et al. Information provision for stroke patients and their caregivers. Cochrane Database Syst Rev 2012; (11): CD001919. [PMC free article: PMC6544775] [PubMed: 23152210]
  • Hackett M, L., Yang M, Anderson Craig S, Horrocks Judith A, House A. Pharmaceutical interventions for emotionalism after stroke. Cochrane Database Syst Rev 2010; (2): CD003690. [PubMed: 15472084]
  • Hackett ML, Yapa C, Parag V, Anderson CS. Frequency of depression after stroke. A systematic review of observational studies. Stroke 2005; 36(6); 1330-40. [PubMed: 15879342]
  • McPherson K, Kersten P, Turner-Stokes L. Background to neurorehabilitation. In Candelise L et al (eds). Evidence-based neurology. London: BMJ Books. 2007.
  • IQWiG health information is written with the aim of helping people understand the advantages and disadvantages of the main treatment options and health care services.

    Because IQWiG is a German institute, some of the information provided here is specific to the German health care system. The suitability of any of the described options in an individual case can be determined by talking to a doctor. We do not offer individual consultations.

    Our information is based on the results of good-quality studies. It is written by a team of health care professionals, scientists and editors, and reviewed by external experts. You can find a detailed description of how our health information is produced and updated in our methods.

© IQWiG (Institute for Quality and Efficiency in Health Care)
Bookshelf ID: NBK279214


Informed Health Links

Related information

  • PMC
    PubMed Central citations
  • PubMed
    Links to PubMed

Recent Activity

Your browsing activity is empty.

Activity recording is turned off.

Turn recording back on

See more...