What is a stroke?

A stroke is a serious medical emergency and a major cause of death and disability all over the world. It occurs mostly in older adults, but can happen to younger adults and even children.

A stroke happens when oxygen-rich blood cannot reach the brain cells. Often this is because a blood vessel in the brain becomes suddenly blocked or bleeds. The brain is an oxygen-hungry organ; it needs about 20% of the body's total oxygen consumption, much more than its relative size and weight. When the blood supply to it is interrupted, brain cells suffer damage within minutes and start dying. This can have far-reaching consequences for the body.

Some people who have had a stroke will recover fully, while others may experience mild or severe disability that may last for the rest of their lives. Speedy treatment of stroke can be crucial to survival and recovery. For this reason, it is important to know how to recognise early signs of a stroke and react accordingly.

In developed countries, a stroke can account for more than 10% of total deaths. [1] In recent years, death rates from stroke in developed countries have been falling due to improvements in prevention and treatment. 

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

Causes and types

There are two main types of stroke - ischaemic stroke and haemorrhagic stroke. Once brain cells are damaged, they are unable to regenerate, potentially leading to persistent disability and even death. 

Ischaemic stroke

Ischaemic strokes account for about 80% of all stroke cases. [1] [2]  An ischemic stroke occurs when an artery supplying oxygen-rich blood into the brain becomes blocked and oxygen cannot reach the brain tissue.

Haemorrhagic stroke

Haemorrhagic strokes account for about 20% of all stroke cases. [1] [2]  A haemorrhagic stroke occurs when a blood vessel in the brain suddenly bleeds. As a result, blood collects in the brain, which causes an increase in pressure that damages brain tissue.

Ischaemic stroke and haemorrhagic stroke are the two major types of stroke.Different effects on the brain tissue during a haemorrhagic and ischaemic stroke. 

Transient ischemic attack

A transient ischemic attack (TIA), also known as a 'mini-stroke', is caused by a temporary blockage or narrowing of a blood vessel leading to the brain. A person experiencing TIA will have signs and symptoms of a stroke, but will recover completely within minutes or a few hours. It is a preliminary sign for a stroke in the near future. 

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

Risk factors

Risk factors for stroke include:

  • Age - anyone can have a stroke, but the risk increases in older adults;
  • High blood pressure (hypertension);
  • Smoking;
  • A poor diet, obesityhigh cholesterol;
  • Diabetes;
  • A sedentary lifestyle;
  • Stress and depression;
  • A family history of stroke;
  • Ethnicity - the chance of stroke is higher in some populations;
  • Excessive alcohol consumption;
  • Heart disease, such as atrial fibrillation, and;
  • Recent transient ischemic attack (TIA) or a previous stroke.

Diabetes

A metabolic disorder that is caused by problems with insulin secretion and regulation and which is characterised by high blood sugar levels. Also known as diabetes mellitus.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

Signs and symptoms

Since a stroke occurs suddenly, its signs and symptoms can appear very quickly. During a stroke, brain cells are starved of oxygen and begin dying within minutes. The expression 'time is brain' in stroke treatment represents the principle that more brain cells are lost as time passes. The time between the start of a stroke and its treatment is therefore crucial.  

Early warning signs - FAST test

The FAST test is a simple set of early warning signs used to recognise a stroke. FAST is an acronym used to remember these points:

  • Face - is the person's face droopy, flaccid, especially just on one side? Can they smile?
  • Arms - can the person lift both their arms above their head?
  • Speech - is the person having problems with speaking and/or understanding speech? Is the speech slurred?
  • Time - the quicker you act, the better the chance of survival and recovery. Call 000, even if the symptoms go away.

The FAST signs - Face, Arms, Speech, and Time - are indicators of a stroke occurring.The FAST test is used to diagnose early warning signs of a stroke. 

Symptoms of a stroke

Symptoms and effects of a stroke can include:

  • Sudden weakness on one side of the body, such as the inability to move or lift the arm;
  • Sudden paralysis of one side of the body;
  • Movement and coordination problems, particularly only on one side;
  • Confusion, memory loss and difficulty with formulating thoughts, speech and understanding speech;
  • Sudden, severe headache;
  • Dizziness, vertigo;
  • Nausea, vomiting;
  • Blurred vision, loss of vision, or seeing only half the regular vision field (hemianopia);
  • Seizure, and;
  • Loss of consciousness.

Paralysis

An inability to move or feel; a loss of muscle function or sensation.

Seizure

A sudden, involuntary contraction of muscle groups caused by abnormal electrical activity in the brain.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

Methods for diagnosis

A doctor will initially suspect stroke based on the symptoms and a physical examination.

A brain scan such as a computerised tomography (CT) scan or magnetic resonance imaging (MRI) is needed to identify the type, location, and severity of the stroke. 

In many cases of stroke, heart activity will also be examined and monitored, as it may be related to heart conditions.

Computerised tomography

A scan that uses X-rays to create a 3D image of the body. This can detect abnormalities more effectively than a simple X-ray can.

Magnetic resonance imaging

A type of imaging that uses a magnetic field and low-energy radio waves, instead of X-rays, to obtain images of organs.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

Types of treatment

Treatment of stroke is broadly divided into two categories - treatment that is given during and immediately after a stroke occurs, and rehabilitation that takes place after the situation has stabilised.

Immediate treatment

Stroke treatment should be done by medical professionals. The immediate concern during a stroke is to restore normal blood flow to the brain. The treatment for the two types of stroke are very different. For an ischemic stroke, treatment involves dissolving the blockage in the artery. For haemorrhagic stroke, the bleeding must be stopped and the pressure on the brain relieved.

Rehabilitation

After the cause of stroke has been successfully treated, the rehabilitation stage can begin. Its general goals are to restore the person to normal function if possible and to prevent complications. The character, length, intensity and outcome of this stage are different for every person.

Rehabilitation follows a cycle composed of these steps:

  • Assessment of the person's condition;
  • Setting goals for this rehabilitation stage, and;
  • Intervention (therapy).

After a certain period, the person's condition is reassessed and the cycle begins again, if needed.

Lifestyle modifications

People recovering from stroke are encouraged to change their lifestyle - to stop smoking, eat a healthier diet and become more physically active to have a healthy weight. In addition, medication may also be prescribed to treat specific problems.

Therapy

In order to help a person adjust to and improve their condition after a stroke, other healthcare professionals can offer assistance, including:

  • Physiotherapy, which will aim to improve the person's physical function and strengthen their limbs;
  • Occupational therapy, which aims to help the person re-learn how to perform daily activities (such as walking, eating and dressing) and modify the lifestyle and surroundings to the person's capabilities;
  • Speech therapy, to help speech and communication capabilities, and;
  • Counselling, to help with any emotional difficulties that arise as a result of the stroke.

The rehabilitation process also includes the affected person's family, who will be taught what to expect and how to adapt to the new circumstances.

Prevention of further strokes

People who have had a stroke are at increased risk of having another. For this reason, after a stroke a person will often be placed on medication that will lower the risk of another stroke happening. Medications to prevent clotting, lower blood pressure and reduce cholesterol levels have been shown to reduce the risk of recurring strokes.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

Potential complications

A stroke can damage any area of the brain. As such, its effects can vary widely depending on which part or parts of the brain have been affected and to what degree.

In addition to the effects of stroke listed in the 'Symptoms' section above, long-term complications of stroke can include:

  • Vision problems;
  • Bowel problems;
  • Incontinence (urinary and bowel);
  • Urinary tract infections;
  • Pain (uncommon), numbness;
  • Swallowing and eating difficulties, leading to nutrition problems as well as pneumonia (caused by food and drink accidentally entering the lungs);
  • Sleeping problems;
  • Emotional problems - such as depression, anxiety or lack of energy. Less common are mood swings, personality changes, psychosis and mania;
  • Balance problems leading to falls;
  • Dementia;
  • The formation of blood clots, including in the legs (deep vein thrombosis) and the lungs (pulmonary embolism), due to prolonged inactivity during recovery from a stroke;
  • Heart problems;
  • Bleeding in the intestines;
  • Recurrent stroke, and;
  • Death.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

2. Van der Worp H.B. and van Gijn J. (2007) Acute ischemic stroke. New England Journal of Medicine 357:572–579.

Prognosis

Stroke is a serious condition and a leading cause of death and disability throughout the world. Unfortunately, about a quarter of all people who have a stroke die within a month; about half die within a year. [1]  Haemorrhagic stroke is particularly fatal, with nearly half of all victims dying within a month. [1]

For those who survive a stroke, rehabilitation will depend on the severity of the stroke. Many people will recover completely within weeks or months. More severe stroke can cause long-term or lifelong disability.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

Prevention

The risk of stroke cannot be completely eliminated, but there are many things you can do to lessen the chance of it happening. These are similar to the steps recommended for stroke rehabilitation and can include:

  • Stopping smoking;
  • Consulting your doctor about reducing high blood pressure;
  • Becoming more physically active;
  • Following a more healthy diet by reducing consumption of fats and salt;
  • Reducing your alcohol consumption to a moderate level, and;
  • Avoiding recreational drugs, such as cocaine, which can increase the risk of strokes.

Awareness

Knowing what stroke looks and feels like can help you recognise it if it happens to you or to others. A quick response will improve the chance of surviving a stroke.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.

1. Donnan G.A. Fisher M. Macleod M. et al. (2008) Stroke. The Lancet 371:1612–1623.