What is Stroke and What Causes Strokes

What is Stroke and What Causes Strokes

Stroke is the 4th leading cause of death in the US, with one person dying every 4 minutes as a result. Approximately 800,000 people have a stroke each year; about one every 4 seconds. Only heart disease, cancer and chronic lower respiratory diseases are more deadly.1-3

Strokes occur due to problems with the blood supply to the brain; either the blood supply is blocked or a blood vessel within the brain ruptures. A stroke is a medical emergency, and treatment must be sought as quickly as possible. “What is Stroke and What Causes Strokes”

There are three main kinds of stroke; ischemic strokes, hemorrhagic strokes and transient ischemic attacks (TIAs), also referred to as mini-strokes. There is a separate Knowledge Center page for transient ischemic attacks“What is Stroke and What Causes Strokes”

You will also see introductions at the end of some sections to any recent developments that have been covered by MNT’s news stories. Also look out for links to information about related conditions. “What is Stroke and What Causes Strokes”

Fast facts on stroke

Here are some key points about stroke. More detail and supporting information is in the main article.

  • During a stroke, the brain does not receive enough oxygen or nutrients, causing brain cells to die.
  • There are three main kinds of stroke: ischemic strokes, hemorrhagic strokes and transient ischemic attacks.
  • Ischemic strokes are caused by a narrowing or blocking of arteries to the brain.
  • Hemorrhagic strokes are caused by blood vessels in and around the brain bursting or leaking.
  • Strokes need to be diagnosed and treated as quickly as possible in order to minimize brain damage.
  • Remembering the F.A.S.T. acronym can help with recognizing the onset of stroke.
  • Treatment depends on the type of stroke.
  • Ischemic strokes can be treated with ‘clot-busting’ drugs.
  • Hemorrhagic strokes can be treated with surgery to repair or block blood vessel weaknesses.
  • The most effective way to prevent strokes is through maintaining a healthy lifestyle.

What is stroke?4

Stroke occurs when the supply of blood to the brain is either interrupted or reduced. When this happens, the brain does not get enough oxygen or nutrients which causes brain cells to die. “What is Stroke and What Causes Strokes”

Skull with red to indicate stroke
Strokes occur due to problems with the blood supply to the brain; either the blood supply is blocked or a blood vessel within the brain ruptures.

There are three main kinds of stroke; ischemic, hemorrhagic and TIA. This article will focus on ischemic and hemorrhagic strokes, as there is a separate Knowledge Center article for TIAs, which goes into specific detail about them. “What is Stroke and What Causes Strokes”

In the US, approximately 40% of stroke deaths are in males, with 60% in females. According to the American Heart Association (AHA), in 2006, the stroke death rates per 100,00 population could be split into specific social groups at 41.7% for white males, 41.1% for white females, 67.7% for black males and 57.0% for black females.“What is Stroke and What Causes Strokes”

Stroke is also more likely to affect people if they are overweight, aged 55 or older, have a personal or family history of stroke, do not exercise much, drink heavily or use illicit drugs.5

What causes stroke?

The different forms of stroke have different specific causes.

Ischemic strokes4

Ischemic strokes are the most common form of stroke, with around 85% of strokes being of this type. They are caused by the arteries that connect to the brain becoming blocked or narrowed, resulting in ischemia – severely reduced blood flow. “What is Stroke and What Causes Strokes”

These blockages are often caused by blood clots, which can form either in the arteries connecting to the brain, or further away before being swept through the bloodstream and into narrower arteries within the brain. Clots can be caused by fatty deposits within the arteries called plaque. “What is Stroke and What Causes Strokes”

man with blood pressure monitoring device
Hypertension can lead to blood vessel ruptures and hemorrhagic strokes.

Hemorrhagic strokes4,6

Hemorrhagic strokes are caused by arteries in the brain either leaking blood or bursting open. The hemorrhaged blood puts pressure on brain cells and damages them. Blood vessels can burst or spill blood in the middle of the brain or near the surface of the brain, sending blood into the space between the brain and the skull. “What is Stroke and What Causes Strokes”

The ruptures can be caused by conditions such ashypertension, trauma, blood-thinning medications andaneurysms (weaknesses in blood vessel walls). “What is Stroke and What Causes Strokes”

Transient ischemic attack (TIA)4,6

TIAs are different from the aforementioned kinds of stroke because the flow of blood to the brain is only disrupted temporarily for a short time. They are similar to ischemic strokes in that they are often caused by blood clots or other debris. “What is Stroke and What Causes Strokes”

TIAs should be regarded as medical emergencies just like the other kinds of stroke, even if the blockage of the artery is temporary. They serve as warning signs for future strokes and indicate that there is a partially blocked artery or clot source in the heart. “What is Stroke and What Causes Strokes”

According to the Centers for Disease Control and Prevention (CDC), over a third of people who experience a TIA go on to have a major stroke within a year if they have not received any treatment. Between 10-15% will have a major stroke within 3 months. “What is Stroke and What Causes Strokes”

Recent developments on stroke causes from MNT news

Common inflammatory disorder increases heart attack, stroke risk

People who have polymyalgia rheumatica – a common inflammatory disorder among seniors that causes pain and stiffness – are more at risk of heart attacks and strokes, according to a new study published in CMAJ. “What is Stroke and What Causes Strokes”

Psychological stress ‘increases risk of stroke’

Depressive symptoms in particular, but also chronic stress in life, increase the risk of older people having a stroke or transient ischemic attack, says researchers, who found feelings of hostility, but not anger, were also a risk factor for cerebrovascular disease“What is Stroke and What Causes Strokes”

Narrowing of the carotid arteries may lead to memory and thinking problems

Problems with learning, memory, thinking and decision-making could be linked to narrowing of the neck’s carotid artery, according to new research presented at the American Academy of Neurology’s 66th Annual Meeting in Philadelphia, PA. “What is Stroke and What Causes Strokes”

‘Possible link between stroke and neck manipulation therapy’

The American Heart Association have published a statement in which they say there may be an association between stroke and therapy involving neck manipulation, although they are unable to confirm whether neck manipulation causes stroke or not. “What is Stroke and What Causes Strokes”

Could growth hormone treatment increase the risk of stroke?

Growth hormone treatment is often used to treat children with growth hormone deficiency, slowed growth rates and delayed puberty. However, a new study has found that there could be a link between this treatment and an increased risk of stroke in early adulthood, leading researchers to urge caution to those considering initiating this treatment. “What is Stroke and What Causes Strokes”

Heavy drinking in midlife increases stroke risk ‘more than diabetes’

It is well known that high blood pressure and diabetes can raise the risk of stroke. But a new twin study finds that, for middle-aged individuals, there may be one factor that increases this risk even more: heavy alcohol consumption. “What is Stroke and What Causes Strokes”

Signs and symptoms7-9

Strokes occur quickly, and as such their symptoms often appear suddenly without warning. The main symptoms are as follows:

  • Confusion, including trouble with speaking and understanding
  • Headache, possibly with altered consciousness or vomiting
  • Numbness of the face, arm or leg, particularly on one side of the body
  • Trouble with seeing, in one or both eyes
  • Trouble with walking, including dizziness and lack of co-ordination.

Strokes can lead to long-term problems. Depending on how quickly it is diagnosed and treated, the patient can experience temporary or permanent disabilities in the aftermath of a stroke. In addition to the problems listed above continuing, patients may also experience the following:

  • Bladder or bowel control problems
  • Depression
  • Pain in the hands and feet that gets worse with movement and temperature changes
  • Paralysis or weakness on one or both sides of the body
  • Trouble controlling or expressing emotions.

Tests and diagnosis7,8,10

Strokes occur quickly, so that often a stroke diagnosis will have to be made before an individual can be seen by a doctor. The acronym FAST is a way to remember the signs of stroke, and can help toward identifying the onset of stroke in someone:

  • Face drooping: if the person tries to smile does one side of the face droop?
  • Arm weakness: if the person tries to raise both their arms does one arm drift downward?
  • Speech difficulty: if the person tries to repeat a simple phrase is their speech slurred or strange?
  • Time to call 911: if any of these signs are observed, contact the emergency services.

It is important that strokes are diagnosed as quickly as possible. The quicker that treatment can be administered, the less damage that will be done to the brain. In order for a stroke patient to get the best diagnosis and treatment possible, they will need to be treated at a hospital within 3 hours of their symptoms first appearing.

Both ischemic strokes and hemorrhagic strokes require different kinds of treatment. Unfortunately, it is only possible to be sure of what type of stroke someone has had by giving them a brain scan in a hospital environment. “What is Stroke and What Causes Strokes”

There are several different types of diagnostic tests that doctors can use in order to pin down precisely what type of stroke has been experienced:11

CT scan of brain
CT scans of the brain are one of the only ways to diagnose what type of stroke a person has had.
  • Physical examination: a doctor will ask about the patient’s symptoms and medical history. They may check blood pressure, listen to the carotid arteries in the neck and examine the blood vessels at the back of the eyes, all to check for indications of clotting
  • Blood tests: a doctor may perform blood tests in order to find out how quickly the patient’s blood clots, what the levels of chemicals within it are like and whether or not the patient has an infection
  • CT scan: a series of X-rays that can show hemorrhages, strokes, tumors and other conditions within the brain
  • MRI scan: radio waves and magnets create an image of the brain to detect damaged brain tissue
  • Carotid ultrasound: an ultrasound scan to check the blood flow of the carotid arteries and to see if there is any plaque present
  • Cerebral angiogram: dyes are injected into the brain’s blood vessels to make them visible under X-ray, in order to give a detailed view of the brain and neck arteries
  • Echocardiogram: a detailed image of the heart is created to check for any sources of clots that could have traveled to the brain to cause a stroke.

Recent developments on stroke diagnosis from MNT news

‘Strokefinder’ helmet makes rapid stroke diagnoses

A helmet that uses microwaves to examine brain tissue has been found to accurately diagnose the type of stroke that a patient has suffered. If developed, the device could lead to early and correct diagnosis of stroke and may improve treatment for what is currently the 4th highest cause of death in the US. “What is Stroke and What Causes Strokes”

New smartphone apps ‘detect epilepsy and improve stroke care’

In these modern times, there is practically a smartphone app for all aspects of life. Now, new research has detailed two new apps that could help people detect epileptic seizures and receive better treatment for stroke. “What is Stroke and What Causes Strokes”

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