A stroke occurs when the blood supply to part of the brain is suddenly interrupted or when a blood vessel in the brain bursts, spilling blood into the spaces surrounding brain cells. Brain cells die when they no longer receive oxygen and nutrients from the blood or there is sudden bleeding into or around the brain. The symptoms of a stroke include sudden numbness or weakness, especially on one side of the body; sudden confusion or trouble speaking or understanding speech; sudden trouble seeing in one or both eyes; sudden trouble with walking, dizziness, or loss of balance or coordination; or sudden severe headache with no known cause. There are two forms of stroke: ischemic – blockage of a blood vessel supplying the brain, and hemorrhagic – bleeding into or around the brain.
Although stroke is a disease of the brain, it can affect the entire body. A common disability that results from stroke is complete paralysis on one side of the body, called hemiplegia. A related disability that is not as debilitating as paralysis is one-sided weakness or hemiparesis. Stroke may cause problems with thinking, awareness, attention, learning, judgment, and memory. Stroke survivors often have problems understanding or forming speech. A stroke can lead to emotional problems. Stroke patients may have difficulty controlling their emotions or may express inappropriate emotions. Many stroke patients experience depression. Stroke survivors may also have numbness or strange sensations. The pain is often worse in the hands and feet and is made worse by movement and temperature changes, especially cold temperatures.
A stroke can happen in two main ways: Something blocks the flow of blood, or something causes bleeding in the brain. A stroke, or “brain attack,” occurs when a blood vessel in the brain becomes blocked or bursts. The brain cannot store oxygen, so it relies on a network of blood vessels to provide it with blood that is rich in oxygen. A stroke results in a lack of blood supply, causing surrounding nerve cells to be cut off from their supply of nutrients and oxygen. When tissue is cut off from its supply of oxygen for more than three to four minutes, it begins to die.
Why does a stroke affect different parts of the body?
Nerve cells in the brain tissue communicate with other cells to control functions including memory, speech and movement. When a stroke occurs, nerve cells in the brain tissue become injured. As a result of this injury, nerve cells cannot communicate with other cells, and functions are impaired. If a stroke occurs on the right side of the brain, the left side of the body is affected, and vice versa.
The loss of blood flow to the brain damages tissues within the brain. Symptoms of a stroke show up in the body parts controlled by the damaged areas of the brain. The sooner a person having a stroke gets care, the better their outcome is likely to be. For this reason, it’s helpful to know the signs of a stroke so you can act quickly. Stroke symptoms can include:
- numbness or weakness in the arm, face, and leg, especially on one side of the body
- trouble speaking or understanding speech
- slurring speech
- vision problems, such as trouble seeing in one or both eyes with vision blackened or blurred, or double vision
- trouble walking
- loss of balance or coordination
- severe, sudden headache with an unknown cause
What lasting effects can a stroke cause?
The effects of a stroke depend on the extent and the location of damage in the brain. Among the many types of disabilities that can result from a stroke are:
- Inability to move part of the body (paralysis)
- Weakness in part of the body
- Numbness in part of the body
- Inability to speak or understand words
- difficulty communicating
- Difficulty swallowing
- Vision loss
- Memory loss, confusion or poor judgment
- Change in personality; emotional problems
Can strokes be prevented?
If you have already had a stroke or are at risk of having a stroke, you can make some heart-healthy lifestyle changes to try to prevent a future stroke:
- Eating a heart-healthy diet
- Aiming for a healthy weight
- Managing stress
- Getting regular physical activity
- Quitting smoking
- Managing your blood pressure and cholesterol levels