A stroke is an interruption of blood flow to an area of the brain that lasts long enough to cause permanent damage to the brain. It can be caused by either a blockage or rupture of arteries supplying the brain with oxygen and nutrients.
A TIA is a temporary interruption in blood flow to an area of the brain that does not last long enough to cause permanent damage to the brain.
Stroke and TIA Symptoms
Short Term
The short-term effects of a stroke and a TIA are the same and can include any combination of the following:
WeaknessNumbness or tinglingVision changesSpeech problems Falling Dropping objectsDroolingDrooping of one side of the face Confusion
The presence and degree of these short-term symptoms depends on which region of the brain is affected by the lack of blood supply during a stroke or a TIA.
Long Term
In the long term, a stroke can cause permanent disability that corresponds to the short-term effects. Usually, the long-term effects of a stroke show some improvement over time. However, a stroke can also get larger or can cause swelling in the brain. So the long-term effects may be even more extensive than the short-term symptoms of the stroke.
A TIA completely resolves and does not cause any long-term effects or handicaps.
Causes
A stroke can be caused by ischemia (lack of blood flow) or hemorrhage (bleeding). A TIA is always caused by temporary ischemia, not bleeding. Bleeding on the brain does not resolve before damage occurs, therefore the symptoms usually are not transient.
The risk factors that lead to an ischemic stroke and a TIA are the same. They include heart disease, blood clotting problems, and blood vessel abnormalities, such as the ones caused by hypertension, diabetes, high cholesterol, and smoking.
A bleeding blood vessel can cause a hemorrhagic stroke, but because the damage of a hemorrhagic stroke is permanent, a bleeding blood vessel does not cause a TIA. However, a damaged blood vessel may cause a TIA before it bleeds.
Prognosis
A stroke may show some improvement or may get worse over time. About 87% of people who experience a stroke survive, but sometimes a stroke can be fatal. Most stroke survivors have some handicap and need physical therapy.
A TIA resolves completely, but often people who had a TIA go on to have recurrent TIAs, or they may have a stroke within minutes, days, or weeks of the initial TIA.
This happens because often the blood vessel interrupted during a TIA is abnormal, so it is prone to becoming interrupted again. Sometimes, after a TIA, a person may have a brain aneurysm rupture or a hemorrhagic stroke if the cause of the TIA was an interruption of blood flow in a blood vessel that later tears and bleeds.
Imaging Changes
A stroke usually causes abnormalities that can be easily visualized on a brain CT or a brain MRI.
Even though a TIA doesn’t cause permanent damage to the brain, the transient ischemic changes can sometimes be detected on a specific MRI sequence called diffusion weighted imaging. In addition, blood vessel abnormalities in the brain or neck can be identified on imaging tests, such as MRI or CT angiography (a test that uses dye to visualize blood vessels) of the head and neck.
Management
If you have a stroke, you will need careful medical management as well as a thorough medical evaluation to see if you have any risk factors so that you can avoid having another stroke. If you have had a TIA, you will also need to make sure you have a comprehensive medical evaluation to identify and manage any stroke risk factors, because a TIA is a strong predictor of stroke.
Prevention
Prevention of strokes and TIAs is based on a healthy lifestyle and management of stroke risk factors. You can reverse your stroke risk. Some people with TIA and strokes may need surgery.
