Transient Ischemic Attack (TIA)
How to Know if Someone Is at Risk for a Ministroke
What is a TIA (ministroke)?
A transient ischemic attack (TIA) -- also called a "ministroke" -- is a brief episode of stroke symptoms caused by low blood flow in arteries within the brain. Unlike an actual stroke, a TIA doesn't result in permanent brain damage, and the symptoms clear up completely. TIAs used to be defined as stroke symptoms that disappeared in less than 24 hours, but the 24-hour specification is no longer part of the definition. TIA symptoms can last from minutes to hours.
TIAs are strong predictors of future stroke: 4 to 10 percent of people develop a true stroke within 48 hours of a TIA, and many others develop strokes within the following three months. So although it may be tempting to ignore a TIA once the symptoms disappear, the attack should be considered an important warning sign that a full-blown stroke may be on the horizon. Stroke risk after TIA is especially high in people who are older than 60, have diabetes, and/or have blood pressure higher than 140/90.
Fortunately, prompt medical evaluation (within 24 hours) of TIAs usually does lead to treatment that reduces stroke risk. Medical evaluation is also needed to properly identify the cause of stroke-like symptoms, since other conditions, such as migraine and seizure, can also cause them.
How TIAs and Strokes Happen
Ischemic strokes and TIAs occur when a vessel carrying blood to the brain becomes blocked, causing the blood flow to a particular area to slow or stop. This usually happens in one of three ways:
- A blood clot forms in a blood vessel in the brain and blocks the vessel.
- A blood clot that formed elsewhere in the body breaks loose and travels to the brain, blocking a vessel.
- A major or minor artery carrying blood to the brain becomes nearly blocked over time, often due to atherosclerosis (buildup of plaque). This causes chronic low blood flow. A further drop in blood flow can then cause a TIA or even a stroke.
In a TIA, the symptoms disappear because blood flow is restored before the brain suffers serious, permanent damage. But even though the symptoms don't linger, some brain injury may have occurred. When a person has multiple small strokes, the damage may add up to vascular dementia: a progressive loss of memory, judgment, and the ability to think and communicate. That's why it's so important that TIAs be taken seriously and treated appropriately.
Signs and Symptoms of a TIA, and What to Do
The symptoms of TIA and ischemic stroke are the same. As with a stroke, the symptoms depend on the area of the brain affected. Your family member probably won't experience all of the symptoms associated with a TIA. And even if she had a TIA or stroke earlier, a second TIA might not cause the same symptoms.
Here's a list of the warning signs of a TIA or ischemic stroke. For more detailed information about stroke, see How to Tell if Your Parent Is Having a Stroke: Signs to Look Out for and What to Do. Call 911 right away if you notice any of these signs:
- Sudden numbness or weakness of the face, arm, or leg -- especially on one side of the body
- Sudden confusion, trouble speaking or understanding
- Sudden trouble seeing in one or both eyes
- Sudden difficulty walking, loss of balance or coordination, dizziness
If someone experiences any of the above symptoms for even the briefest amount of time, call 911 immediately. Make a note of the exact time when the symptoms began. This information can be extremely helpful to the emergency room personnel.
Even if you suspect the symptoms are caused by a TIA rather than a stroke, don't wait to see whether the symptoms go away. If it's a stroke, the person needs emergency medical care immediately. If it's a TIA, the doctor needs to evaluate her, treat the cause of the TIA, and then set up a plan to prevent a future stroke.
Your family member or friend may not want to seek treatment for a TIA, especially if the symptoms disappear quickly. She may brush it off as aches and pains, hunger, fatigue, or just old age. But even if she's very persuasive, don't let her talk you out of seeking medical attention, since there's a high risk of stroke in the 24 to 48 hours immediately following a TIA.
If she didn't tell you about the TIA right away or managed to persuade you not to call 911, it's not too late. Call the doctor as soon as possible to make sure your family member gets the treatment she needs.
What to Expect From the Doctor After a TIA
The doctor will focus on two separate issues: First, what caused the episode, and second, how to treat the cause and prevent future strokes.
- Determine the cause of the TIA. Whether a patient goes to the emergency room or schedules an appointment after the TIA, the doctor will probably do one or more of the following:
- Check the patient's blood pressure to make sure it's within normal range
- Order a carotid ultrasound to see whether the carotid artery is blocked
- Test for atrial fibrillation, a condition that can cause blood clots to form in the heart
- Schedule a CT or MRI scan to look for brain injury
- Schedule a special CT or MRI to look for narrowing of the arteries in the brain
- Check for heart disease
- Check cholesterol levels
- Treat the cause and prevent future strokes. The type of treatment the doctor recommends will depend on the cause of the TIA. The doctor may prescribe medication to control blood pressure, lower cholesterol, or slow blood clotting. If tests reveal a blockage in the carotid artery, your friend or family member may need to undergo a procedure to remove the blockage or increase blood flow. Regardless of how the TIA is treated, the patient will need to take steps to prevent a future stroke, including quitting smoking if applicable. The doctor will help you and her come up with a plan to reduce the risk. For other practical tips, see 10 Ways to Help Your Parent Prevent a Stroke.
Although a TIA and the possibility of a stroke may leave you feeling overwhelmed and frightened, there's actually a bright side: You and your family member have been given the gift of a wake-up call. By seeking medical advice, getting the appropriate treatment, and making lifestyle changes, your family member may be able to avoid a serious stroke.