Causes of strokes

The risk factors that determine how likely it is you will have a stroke include:

• High blood pressure:
  The leading cause of both ischemic and hemorrhagic stroke. The heart works too hard and the blood vessels become strained. It speeds up hardening of the arteries, dislodging plaque formations that can block blood vessels.
• Diabetes:
  This disease speeds up hardening of arteries.
• Smoking:
  The carbon monoxide in cigarette smoke makes it harder for the blood to carry oxygen, making the heart work harder. As well, nicotine makes the heart beat faster and causes blood vessels to narrow. Smokers have a 50 per cent higher chance of having a stroke than non-smokers.
• Obesity:
  Being obese increases the chances of high blood pressure and high cholesterol.
• Alcohol:
  Excessive alcohol consumption can raise blood pressure.
• Increasing age:
  Older people have a greater stroke risk. After age 55, stroke risk doubles every 10 years.
• Gender:
  Strokes are more common in men.
• Heredity:
  The risk of a stroke increases if a parent, sibling or grandparent had a stroke.
• Prior stroke:
  Someone who has already had a stroke is at higher risk of having another.

Symptoms

These warning signs mean you may be having a stroke:

• Weakness, numbness or tingling in face, arms or legs, especially on one side of the body.
• Trouble speaking or understanding speech.
• Sudden blurring, double vision or loss of vision.
• Sudden severe headache.
• Dizziness, loss of balance.

One of the most important warnings that a stroke may happen in the near future is what’s called a transient ischemic attack.

Also called a “mini-stroke” or “warning stroke,” these attacks occur when a blood clot blocks an artery, shutting off the brain’s blood supply. They can last seconds or minutes, and resolve themselves without permanent brain damage, but they can cause vision problems, numbness in an arm, slurred speech or facial weakness.

The effects of a stroke depend on what part of the brain loses its supply of oxygen-rich blood.

Brain stem
Located at the base of the brain, the brain stem controls functions such as breathing, swallowing, heartbeats and eye movement. Effects of a stroke here can include difficulty speaking, swallowing or breathing, paralysis, loss of balance and hand-eye co-ordination problems.

Cerebellum
Found at the bottom of the brain in the back of the head, the cerebellum controls simple movements and balance. A stroke in this area can cause problems walking, maintaining balance and co-ordination.

Cerebrum
The main part of the brain that controls muscle movement, thinking and intelligence. A stroke on the right side of the cerebrum can cause weakness or paralysis in the left side of the body, vision problems, difficulty with depth perception, memory problems, and changes in behaviour, such as inappropriateness and depression. A stroke on the left side can cause weakness or paralysis in the body's right side, problems understanding language, difficulty with math, reasoning, reading, writing and memory.

Stroke Causes & symptoms Diagnosis & treatment Quiz Rates by province Milestones More information

Healthy advice