I RECENTLY had a spell of confusion and difficulty speaking. It only lasted a few minutes, but my wife insisted I see my doctor, who believes it was a “mini stroke”. How serious is this? Should I be worried about it happening again?
A transient ischemic attack (TIA), also known as a “mini stroke”, is a blood vessel blockage that comes and goes quickly. TIAs were once written off as fleeting problems that posed little danger once they had passed. But now doctors understand that these brief episodes predict trouble ahead. Research shows that a TIA is often followed by a full-blown stroke, and treating it as an emergency can help prevent brain damage.
A TIA occurs when part of the brain is suddenly deprived of oxygen. The symptoms depend on which physical or mental functions are controlled by the part of the brain that’s been affected. The trouble starts when a blood clot or bit of cholesterol-clogged plaque lodges in an artery nourishing the brain. The blockage is small enough or fragile enough that the body’s self-repair systems can clear the artery, usually within an hour, although sometimes it takes up to a day. Larger, more durable blockages cause a stroke, that is characterised by long-lasting problems.
The main difference between a stroke and a TIA is what happens to the brain tissue. A stroke kills brain cells. But if a blockage is cleared quickly, so the brain’s blood supply is restored, the event is a TIA. The difference is that the interruption in blood flow was short (transient). The affected brain cells ceased to function temporarily, but they recovered.
The consensus is that a TIA should be treated every bit as seriously as a full-blown stroke. And, in fact, full strokes can start out just like TIAs. For this reason, although your symptoms resolve, you should consider a TIA as a warning of a future stroke.
TIAs that last more than a few hours may cause some brain damage. If symptoms last as long as 24 hours (at which point the episode is automatically classified as a stroke), it is likely that the TIA has caused some amount of tissue death. Advances in brain imaging have revealed that tissue death may occur even in TIAs that end much earlier — and even if symptoms have resolved. In these cases, the affected tissue is in a “silent” area of the brain, so that damage produces no symptoms. Or the damaged area may have produced symptoms but then recovered, causing the symptoms to disappear.
It is important not to brush off a TIA. Treating it as an emergency, just as you would treat chest pain, may nip a TIA in the bud, minimise permanent brain damage and help prevent the long-lasting disability of a stroke.
Call your local emergency medical services number if you or someone with you suddenly experiences one or more of these symptoms — even if the symptoms start to fade away.
• Numbness or weakness in the face, arm or leg, especially on one side of the body.
• Inability to move the fingers, hand, arm or leg.
• Slurred speech or other trouble speaking.
• Difficulty understanding what someone is saying.
• Trouble seeing with one or both eyes or hearing with one or both ears.
• Dizziness, trouble walking, or loss of balance or co-ordination.
• A sudden and severe headache.
Anyone having a TIA should receive emergency care as soon as possible. He or she might be given aspirin or another medication to help control blood clotting. If the symptoms have passed, treatment focuses on what might be ahead, not on what just happened. And the sooner you get started, the better.
The National Stroke Association recommends evaluation by a stroke specialist. He or she may order a scan of your brain and carotid arteries, the main arteries that deliver blood to the brain. Identifying what caused the TIA is important for planning the strongest defence against another TIA or a stroke.
Each year, more than a quarter-million Americans have TIAs, and many suffer the consequences. If you have another “spell”, don’t waste a minute getting help.
• For more information, visit www.health.harvard.edu