What is a transient ischemic attack (TIA)?
Various events or conditions can cause the brain to be deprived of oxygen. Symptoms of a transient ischemic attack (TIA) are similar to those of a stroke, but they do not last as long.
It is estimated that up to 500,000 people in the United States experience a TIA each year.
Because symptoms fade away rapidly, most patients do not seek medical help. However, between 10-15 percent of TIA patients have a full-blown stroke within 3 months. This is why recognizing the signs of a TIA and seeking medical attention is important.
Rapid evaluation and treatment of people who experienced a mini-stroke, either in specially designed TIA clinics or the emergency room, can significantly reduce the risk of a subsequent stroke.
- A mini-stroke occurs when blood is temporarily cut off to regions of the brain.
- Around 500,000 Americans have a stroke each year.
- Rapid care is essential to minimize the medical implications of a stroke.
- The object of TIA treatment is to prevent further occurrences.
- One of the most common drugs used to prevent TIAs is warfarin, an anticoagulant medication.
What is a TIA?
The acronym FAST represents the signs and symptoms of stroke.
A transient ischemic attack (TIA) is like a stroke in that it produces similar symptoms, but it only lasts a few minutes and causes no permanent damage. It is sometimes called a mini-stroke.
It happens when there is not enough oxygen reaching the brain. This is often due to a blood clot that remains for a short while.
When the clot breaks up or moves on, symptoms subside.
The American Stroke Association (ASA) urges people not to ignore a TIA, as it can be a warning of a future, full-blown stroke.
People with TIA experience varying symptoms, depending on which part of the brain is affected.
The signs and symptoms of a TIA are represented by the acronym FAST (Face, Arms, Speech, Time):
- Face: The face may fall on one side as some of the facial muscles become paralyzed. The person's eye or mouth may droop, and they may be unable to smile properly.
- Arms: Arm weakness or numbness might make it hard for the individual to either raise both arms or to keep them raised.
- Speech: Speech may be slurred and garbled.
- Time: If just one of these symptoms are present, it is time to dial emergency services.
Being able to identify the signs and symptoms present in FAST is especially important if you live with somebody in a high-risk group, such as an older adult, or an individual with high blood pressure or diabetes. FAST is also a reminder that the sooner medical treatment is sought, the better the chance of recovery.
Other signs and symptoms of a TIA can include:
- difficulty talking
- difficulty understanding what others are talking about
- problems swallowing
- very bad headache
- paralysis, numbness, or weakness on one side of the body
- in severe cases loss of consciousness
If anybody experiences any of these signs and symptoms themselves or witnesses anybody else experiencing them, medical attention should be sought immediately. TIA symptoms are temporary and should disappear within 24 hours. They may last from 2-15 minutes.
Which conditions can mimic a TIA?
Recognizing a TIA can be complicated, especially as other conditions can produce similar symptoms and bodily effects.
- low blood sugar
- minor seizures
The way to rule out these other conditions is that a TIA will often heavily impact one part of the body, such as sensation and movement in a single limb or vision. This is due to a TIA's effect in blocking a single blood vessel. Conditions that mimic a TIA will generally cause bodywide neurological symptoms, such as tingling or fainting.
To prevent TIA developing into a full-blown stroke, it is vital to have any symptoms checked that could suggest the presence of a TIA.
A TIA happens when the supply of oxygen to the brain is disrupted.
Disruption of blood supply
Two main blood vessels called the carotid arteries supply blood to the brain. These arteries branch off into many smaller blood vessels. A TIA can occur if one of the smaller blood vessels becomes blocked, depriving that part of the brain of oxygen-rich blood.
Atherosclerosis causes arteries to narrow. Fatty deposits develop on the inner lining of blood vessels, causing them to become hardened, thickened, and less flexible. This makes it much more difficult for the blood to flow around the body.
A blood clot can disrupt the supply of oxygen-rich blood to parts of the brain. Blood clots are usually caused by:
- Heart conditions, such as congestive heart muscle disease or atrial fibrillation.
- Blood conditions, including leukemia (blood cell cancer) and sickle cell anemia.
An embolism is a blood clot from one part of the body that becomes dislodged and travels into one of the arteries that supplies the brain. An embolism can cause a TIA.
Hemorrhage (internal bleeding)
A minor brain hemorrhage (small amount of bleeding in the brain) can cause a TIA; however, this is rare.
Risk factors for TIA include ethnic origin, age, and family history.
There are some risk factors for TIA that can be changed, and others that cannot.
Risk factors that cannot be changed:
- Family history: People with a close relative who has had a stroke or TIA.
- Age: People aged over 55 have a higher risk of having a TIA.
- Sex: Males are at slightly greater risk.
- Ethnic origin: People of black African ancestry have a higher risk.
Risk factors that can be changed:
- Hypertension, or high blood pressure.
- Cardiovascular disease: People with cardiovascular diseases are at greater risk of having a TIA. This includes a heart defect, heart failure, or arrhythmia (abnormal heart rhythm).
- Carotid artery disease: This develops when blood vessels in the neck leading to the brain are clogged.
- PAD (peripheral artery disease): When blood vessels that carry blood to the arms and legs become clogged.
- Smoking: People who smoke increase their risk of developing various diseases and conditions, including TIA and stroke.
- Sedentary lifestyle: People who are physically inactive have a significantly higher risk.
- Diabetes: People with diabetes are more likely to suffer from atherosclerosis (narrowing of the arteries due to a buildup of fatty deposits).
- Bad diet: Individuals who consume too much bad quality fat and or salt have a higher risk of stroke and TIA.
- Blood cholesterol levels: If blood cholesterol levels are high, it increases the risk of TIA or stroke.
- Homocysteine levels: Homocysteine is an amino acid produced by the body as a byproduct of consuming meat. Elevated levels of homocysteine in the blood can make the arteries thicken and scar; they are more susceptible to clogs.
- Bodyweight: Obese people have a significantly higher risk of having a TIA or stroke.
- Alcohol: People who drink large quantities of alcohol regularly are also at higher risk.
- Illegal drugs: Some illegal drugs, such as cocaine, can raise the risk of stroke or TIA if taken often enough.
Treatment will depend on the cause of the TIA. The doctor may prescribe medication that lowers the risk of a blood clot, or recommend surgery or an angioplasty.
The type of medication prescribed will depend on what caused the TIA, how severe it was, and what part of the brain was affected.
Anti-platelet drugs: These make platelets in the blood less likely to stick together and form a clot that can block blood flow. Anti-platelet drugs include:
Aspirin and dipyridamole: Some doctors may prescribe Aggrenox, which contains both aspirin and dipyridamole. Some doctors may recommend ticlopidine (Ticlid).
Side effects of aspirin can include:
- ringing in the ears
- stomach irritation and bleeding
Side effects of dipyridamole may include:
Clopidogrel: If a person has experienced severe side effects from taking aspirin, had a further TIA despite taking aspirin, or has arterial disease, the doctor may prescribe clopidogrel (Plavix).
Side effects of clopidogrel may include:
- abdominal pain
Anticoagulants: Anti-coagulants interfere with many other medications, other over-the-counter drugs, and herbs. Always talk to your doctor before taking any other medication or herbs when on anticoagulants.
Warfarin (Coumadin) and heparin: Warfarin can be used long-term, while heparin is used short-term.
Other side effects may include:
- blood in urine
- blood in feces (either specks of blood, or feces are black)
- severe bruising
- nosebleeds that persist for more than 10 minutes
- blood in vomit
- coughing up blood
- unexplained headaches
- bleeding from the vagina
- heavy or increased bleeding during menstruation
Medications for hypertension: Various medications are available to treat blood pressure. However, if an individual is unfit and overweight, blood pressure can often be brought down by losing weight, doing exercise, getting at least 7 hours good quality sleep every night, and eating a well-balanced healthful diet.
Medications for cholesterol: As with hypertension, losing weight, following a well-balanced diet, doing regular exercise, and sleeping at least 7 hours every night can help bring cholesterol levels back to normal. Sometimes medications are necessary and the person may be prescribed a statin, which helps reduce the production of cholesterol.
An operation called a carotid endarterectomy involves removing part of the lining of the damaged carotid artery, as well as any blockage that has accumulated in the artery.
This operation is not suitable for people whose arteries are nearly completely blocked. Even some people with partial blockage may not be suitable for this procedure because of the risk of stroke during the operation.
A number of tests may be necessary to fully understand the neurological causes of the TIA.
Anybody who has signs and symptoms of a TIA should seek medical attention immediately. As TIAs do not last very long, it is possible that the symptoms will have disappeared by the time the person gets to see their doctor.
If at all possible, the person should take someone who witnessed the event with them; so that they can share what symptoms they saw.
The doctor may need to carry out a neurological examination, even if symptoms have gone. This will include some simple tests to check skills, such as memory and coordination.
While being examined, the doctor will ask the person questions regarding symptoms, such as:
- How long they lasted?
- What they were like?
- How the symptoms affected them?
The answers given will help the doctor rule out any other conditions that may have similar symptoms.
If the doctor believes the person had a TIA, they will be referred to a neurologist for further testing. The specialist may order a number of tests designed to identify the underlying factors that caused the TIA.
The tests include:
- Blood tests: Tests will check blood pressure, cholesterol levels and clotting ability.
- Electrocardiogram (ECG): This records the electrical activity and rhythms of the heart.
- Echocardiogram: This is an ultrasound scan that checks the pumping action of the person's heart.
- Chest X-ray: This helps the doctor rule out other conditions.
- CT scan: The scan creates a 3-D image that can show aneurysms, bleeding, or abnormal vessels within the brain.
- MRI scan: An MRI gives a more detailed view of the brain than a CT scan, and helps identify any brain damage.
- Ultrasound: A wand waved over the carotid arteries in the neck can provide a picture that indicates any narrowing or clotting.
Smoking is a significant risk factor in strokes.
The measures below can help reduce the risk of having a TIA, stroke, or a recurrent TIA:
- Giving up smoking reduces the risk of stroke, TIA, and many other conditions.
- Following a well-balanced diet, with plenty of fruit and vegetables, whole grains, fish, poultry, and very lean meat. Avoiding all junk foods and foods with bad fats, such as saturated and trans fats, may also be helpful.
- Reducing salt (sodium) intake. Individuals prone to high blood pressure should avoid salty foods and not add salt to cooking.
- Exercising moderately for at least 30 minutes five times a week. However, people should check with their doctor before they begin an exercise program.
- Reducing the amount of alcohol consumed. Either don't drink alcohol at all, or stay within the daily recommended limits.
- Losing weight and bringing body weight down to normal levels will decrease risk.
- Taking illegal drugs, such as cocaine, significantly raises the risk of stroke and TIA.
- Controlling diabetes through proper medication and sticking to treatment plans greatly reduces the risk of stroke and TIA.
- Getting at least 7 hours good quality, continuous sleep every day.