What is Transient Ischemic Attack?
A transient ischemic attack (TIA), also known as a “mini-stroke,” is a medical emergency. It happens when there’s a sudden, brief decrease in blood flow to the brain, spinal cord, or retina, the part of the eye that sends images to the brain. However, this doesn’t lead to any permanent tissue damage. In the past, a TIA was defined by how long it lasted, but now it’s defined by whether or not it damages tissue.
A TIA usually lasts less than an hour, often just a few minutes. It’s a major warning sign of a possible major stroke, and the risk is highest in the first 48 hours after a TIA. It’s crucial to tell the difference between a TIA and other conditions that resemble it. TIAs are often associated with temporary loss of certain brain functions, such as speech or movement, caused by underlying diseases affecting the arteries in the brain. They always start suddenly.
After a TIA, doctors will conduct immediate tests, like imaging and lab studies, to help prevent a potential full-blown stroke. A simple measure can be used to determine the likelihood of a future TIA or major stroke. Immediate treatments should be started to control factors that increase stroke risk. These measures may include controlling blood pressure and blood sugar levels, high-dose cholesterol-lowering medication, blood-thinning medications, dietary changes and exercises. Any specific underlying causes also need to be treated. This treatment plan can significantly lower the risk of another stroke or TIA by at least 80%.
What Causes Transient Ischemic Attack?
A transient ischemic attack (TIA), also known as a mini-stroke, can be classified into different types, much like a full-blown stroke. These include large artery blockage due to fat deposits (atherothrombosis), blockage originating from the heart (cardiac embolism), blockage in small blood vessels (lacunar), and unknown causes (cryptogenic). There are also less common types like blood vessel tearing (vascular dissection) and blood vessel inflammation (vasculitis).
Many factors contribute to the risk of having a TIA. These include diabetes, high blood pressure, age, smoking, obesity, alcohol abuse, unhealthy diet, mental stress, and lack of regular exercise. If you’ve had a stroke or TIA before, your chances of experiencing another one significantly increase.
Out of all these risk factors, high blood pressure is the most important. It poses a significant risk for the individual and is a common issue in many people.
Risk Factors and Frequency for Transient Ischemic Attack
It’s hard to figure out how many people have Transient Ischemic Attack (TIA) because other health issues look like it. However, we believe TIA impacts around half a million people in the United States each year, which is about 1.1 for every 1000 people in the country. On average, about 2% of adults in the US experience TIA. We also know that if someone has had a stroke in the past, it increases the likelihood of them having TIA. Some studies have shown that most people who had a stroke for the first time had previously shown symptoms of TIA.
Signs and Symptoms of Transient Ischemic Attack
A transient ischemic attack (TIA) is a brief interruption of blood flow to part of the brain, commonly known as a mini-stroke. The symptoms are often gone by the time the person sees a doctor or gets to the emergency room. When talking to the doctor, it is important to give details about what happened. This includes when the symptoms started, how long they lasted, and anything else that happened. The doctor will also ask about certain risk factors. These might be heart disease, smoking, drug use, being overweight, diabetes, high cholesterol, and high blood pressure. They’ll also ask about personal or family history of disorders that increase blood clotting, stroke, or TIA. Specific types of TIA can be suggested by things like a history of irregular heart rhythm or a recent heart attack; symptoms like transient loss of vision that might indicate an issue with the major artery in the neck; and brain-related symptoms such as problems with language or vision.
In a physical examination, the doctor will look for signs of neurological function problems and speech difficulties, which are the most common symptoms in TIA. They may be able to find signs of TIA like vision loss in one eye, uncoordinated eye movements, facial drooping, blindness in one side of the field of vision, double vision, abnormal tongue movement, trouble swallowing, and hearing problems. They may also find signs like weakness on one side of the body or in the face, tongue, hands, or feet; increased muscle tone; rapid muscle contractions; rigidity; and abnormal reflexes. The doctor will also listen to the heart and the arteries in the neck for abnormal sounds, and examine the back of the eye to look for changes due to high blood pressure or diabetes, or signs of blockage in one of the neck arteries.
Testing for Transient Ischemic Attack
When someone has a Transient Ischemic Attack (TIA), it’s a warning sign that the person might have a stroke in the future. A TIA, also called a mini-stroke, usually doesn’t cause permanent damage, but it’s important to get it checked out because it could signal a bigger problem.
The main goals of checking out a TIA are:
- Proof that the symptoms come from a blood vessel problem. This could mean finding signs of low blood flow to the brain and/or a very recent stroke, or finding a possible cause like a blocked blood vessel.
- Rule out other possible causes for the symptoms that aren’t related to blood flow issues.
- Find out what specifically caused the TIA, such as a large-vessel blockage, a tiny clot coming from the heart, or a small blockage in the deep parts of the brain. This helps doctors choose the best treatment to prevent another TIA or a stroke.
- Figure out the chances of a stroke or another TIA happening in the future.
The American Heart Association and the American Stroke Association recommended back in 2009 that a patient who’s had a TIA get brain imaging, preferably an MRI, within 24 hours of experiencing symptoms. If a patient can’t get an MRI, then a CT scan should be used instead. An MRI is better than a CT scan for spotting small areas of brain damage that can be caused by a TIA.
There are other tests your doctor might order, such as checking out the large blood vessels in your neck to see if they’re blocked or narrowed (using carotid ultrasound, magnetic resonance angiography, or CT angiography), or looking at your heart with an ECG and other forms of echocardiogram to see if there’s anything that might cause a blood clot to go to your brain.
The National Stroke Association has certain guidelines for checking out a TIA. They recommend a complete blood count, blood thinning tests (PT/INR), comprehensive metabolic panel, fasting blood sugar test, a lipid panel, a urine drug screen, and an ESR (a simple test that indirectly measures inflammation in your body).
Doctors use a scoring system known as the ABCD2 score to determine the risk for having a stroke after a TIA. “A” stands for age, “B” for blood pressure, “C” for clinical symptoms, “D” for the duration of TIA, and “2” for diabetes. Points are assigned based on specific criteria – for example, being older than 60 years gives you 1 point, as does having high blood pressure at your first check-up. If you have certain symptoms or if the TIA lasted for a certain amount of time, that can give you 1 or 2 points. Having diabetes gives you 1 point. The total score will then be used to determine the risk of having a stroke. Patients with a high score may be admitted to a stroke center for close monitoring and management.
Treatment Options for Transient Ischemic Attack
The main goal of treating a transient ischemic attack (TIA), often referred to as a mini-stroke, is to lower the chance of having another one or a full-blown stroke. Getting treatment quickly can considerably reduce the risk of a stroke after a TIA. Without intervention, there’s approximately a 20% chance of having a stroke within three months after a TIA, and about half of these strokes happen in the first two days. Thus, quickly evaluating the condition of the blood vessels and checking for signs of irregular heart rhythms is extremely important to prevent future strokes. Treating a TIA should predominantly aim at addressing the root causes of the condition.
Recent research has stressed the significance of quick evaluation and treatment as well as combination therapy. The EXPRESS study from the UK demonstrated that early intervention significantly reduced stroke risk by 80%. Further, a 2007 analysis suggested that a combined approach of diet, exercise, clot prevention medication, cholesterol-lowering medication (statins), and blood pressure medication could reduce the chances of a subsequent stroke by 80% to 90%.
More recent studies, such as the CHANCE trial in China and the multinational POINTE trial, emphasized the benefits of dual blood-thinning medication (aspirin and clopidogrel) for 1 month, followed by a single blood-thinning medication. This method seems to be the best plan for anti-clotting therapy.
Other parts of the treatment will depend on the underlying cause of the TIA. For example, if leg or neck artery narrowing (stenosis) of 70% or more is causing your TIA, a procedure to restore blood flow may be recommended. In some instances, surgically cleaning out the buildup in the carotid arteries (carotid endarterectomy) may have better results compared to inserting a stent. However, whether surgery is necessary for patients with a 50-69% narrowing depends on the expected outcomes and potential complications, particularly given the significant improvements seen with aggressive medication use alone.
If the TIA is caused by abnormal heart rhythms (atrial fibrillation) or other heart-related issues, blood-thinning medications (anticoagulants) may be suggested. These medications help prevent clots from forming, therefore reducing the likelihood of another TIA or stroke.
What else can Transient Ischemic Attack be?
Certain medical conditions can sometimes show similar symptoms. These include:
- Carotid artery dissection
- Meningitis
- Meningococcal meningitis
- Multiple sclerosis
- Ischemic stroke
- Hemorrhagic stroke
- Subarachnoid hemorrhage
- Syncope (fainting)
Healthcare professionals need to distinguish between these conditions to accurately diagnose and treat the patient.
