A stroke is a medical emergency that happens when the blood supply to part of the brain is decreased or stopped. When blood flow to the brain is blocked or reduced, brain cells begin to die due to lack of oxygen and nutrients. A stroke requires immediate medical attention to prevent permanent damage to the brain and other organs in the body.
However, in some cases, minor strokes or transient ischemic attacks (TIAs) can occur prior to a full stroke. Recognizing and acting on the symptoms of these pre strokes or warning signs is crucial for getting fast treatment to prevent a major stroke.
What is a pre stroke or transient ischemic attack (TIA)?
A pre stroke, also called a transient ischemic attack (TIA), is caused by a temporary blockage or reduction of blood flow to the brain. The symptoms of a TIA are similar to those of an ischemic stroke but do not last as long.
With a TIA, the blockage that stops oxygen-rich blood from reaching the brain is temporary, so there is no permanent damage. However, a person who experiences a TIA is at high risk of having a full stroke in the near future if the underlying cause of the blockage is not treated.
Key differences between TIAs and ischemic strokes
| Transient ischemic attack (TIA) | Ischemic stroke |
|---|---|
| Temporary disruption of blood flow to the brain | Permanent disruption of blood flow to the brain |
| Symptoms last less than 1 hour, usually 10 to 20 minutes | Symptoms last longer than 1 hour |
| No permanent brain damage | Permanent brain damage possible |
| Full recovery | May have long-lasting disabilities |
The temporary loss of blood flow during a TIA causes neurologic symptoms, but brain tissue does not become permanently damaged. However, TIAs require urgent evaluation because they identify people at risk of having an ischemic stroke.
What causes a pre stroke or TIA?
The underlying mechanism of a TIA is the same as that of an ischemic stroke. With both conditions, a blood clot or plaque blocks an artery supplying blood to the brain. The difference lies in how long the blockage persists:
– During a TIA, the blockage is transient and lasts under an hour before dissolving or dislodging on its own.
– In an ischemic stroke, the blockage persists for longer than an hour and causes permanent damage to brain tissue.
Some common causes of blood clots or plaque buildup that can lead to TIAs and ischemic strokes include:
– Atherosclerosis – This condition causes fatty deposits called plaque to build up inside the arteries over many years. Plaque narrows arteries and makes them rigid. A piece of plaque can break off and travel in the bloodstream to the brain, blocking blood flow.
– Blood clots – Clots can form in arteries narrowed from atherosclerosis. Clots also sometimes form in people with irregular heart rhythms, like atrial fibrillation. A clot can travel to the brain and cause a TIA or stroke.
– Carotid or vertebral artery dissection – A tear in a major artery that supplies blood to the brain allows blood to enter and form a clot within the arterial wall. This compromises blood flow.
– Blood cell disorders – Conditions like sickle cell anemia or polycythemia vera increase risk for blood clots.
Risk factors
Many risk factors for TIAs are similar to those for ischemic strokes:
– Age – The risk increases over age 55.
– High blood pressure
– High cholesterol
– Diabetes
– Smoking cigarettes
– Obesity
– Physical inactivity
– Sleep apnea
– Heavy alcohol consumption
– Illegal drug use
– Personal or family history of stroke, TIA, or heart disease
– Ethnic background – African Americans, Hispanics, and Asian Americans face higher risks.
– Gender – Men have a higher risk until age 75, then women have a higher risk as they age.
What are the symptoms of a pre stroke or TIA?
The symptoms of a TIA are similar to those of a stroke but do not last as long. Common TIA symptoms include:
1. Weakness or numbness on one side of the body
This affects the face, arm, or leg on one side. The weakness is sudden and makes it hard to control the affected muscles. Numbness feels like pins and needles.
2. Trouble speaking
Slurred speech happens when part of the brain involved in producing speech is affected. The person knows what they want to say, but the words come out wrong or don’t come out at all.
3. Temporary loss of vision
Sudden blurred vision or blindness in one or both eyes is common. Double vision or loss of peripheral vision can also occur.
4. Dizziness or loss of balance and coordination
This feels like the room is spinning or moving. The person may feel unsteady on their feet and stumble or almost fall.
5. Confusion
Thinking abilities seem foggy. The person may be very disoriented about time and place.
6. Difficulty swallowing
Nerves controlling the throat and swallowing are affected. Food or drink may go down the wrong way.
7. Headache
Some people have a sudden, severe headache right before other TIA symptoms start. The headache may indicate a blood vessel rupture leading to bleeding in the brain.
How long do TIA symptoms last?
By definition, the neurologic symptoms caused by a TIA resolve within an hour, though most only last about 10 to 20 minutes. The symptoms disappear quickly once the temporary blockage clears and normal blood flow to the brain resumes. Any symptoms lasting longer than an hour likely signal an ischemic stroke instead of a TIA.
However, other TIA-related symptoms may linger after the attack itself passes. This includes:
– Fatigue – Weakness and tiredness may persist for hours up to days after the TIA. The brain needs time to recover.
– Confusion – Thinking and speaking abilities may remain fuzzy initially.
– Headache – A severe headache after the TIA often gradually improves within several hours but sometimes lasts a day or two.
Are TIAs dangerous?
Though TIAs do not leave permanent damage, they should never be ignored or downplayed. Approximately 15% of strokes occur in people who had a recent TIA.
About one-third of people who experience a TIA end up having a stroke within a year if underlying risk factors are not addressed. Half of these strokes happen within 2 days of the TIA. The more TIAs someone has, the higher their risk of stroke.
Risk of stroke after TIA
| Time after TIA | Risk of stroke |
|---|---|
| Within 2 days | About 10-15% |
| Within 30 days | About 20% |
| Within 3 months | About 30% |
| Within 1 year | About 33% |
TIAs require emergency care to search for underlying causes and prevent a major stroke. A TIA indicates disrupted blood flow is already happening in the brain’s arteries. Prompt treatment of plaque buildup or clots causing the disruption can help prevent imminent stroke.
What should you do if you think you are having a TIA?
If you experience any sudden neurologic symptoms that you think could be a TIA, it is vital to seek emergency care right away instead of waiting for symptoms to resolve. Call 911 or have someone drive you to the ER immediately. Ambulance personnel can start evaluating you en route.
Note when your symptoms started and specifically describe them to the 911 operator and your doctors. Details about your symptoms and their exact timing help determine treatment.
Getting medical care rapidly during a TIA gives you the best chance for doctors to identify the cause and intervene before it leads to a major stroke. Do not ignore symptoms even if they go away. Call for help without delay.
What to do during a possible TIA:
– Call 911 or have someone drive you to the ER right away.
– Note the exact time when symptoms started.
– Describe your symptoms clearly to 911 and medical staff.
– Take aspirin if you have it available. This helps slow clotting.
– Take any prescriptions with you to show doctors at the hospital.
How is a TIA diagnosed?
Doctors perform a neurological exam to identify any lingering symptoms or deficits from the TIA that provide clues to which artery and part of your brain were affected. They also evaluate your full medical history.
Diagnostic tests help confirm a TIA, reveal what caused it, and guide treatment:
Brain imaging
– CT or MRI scan – This looks for evidence of ischemia and lesions in the brain. The scans are often done first.
– MRI with diffusion-weighted imaging (DWI) – DWI can detect tiny new ischemic lesions in the brain missed on regular MRI after some TIAs.
– MR angiography – Provides images of blood vessels in the brain to reveal areas of narrowing or blockages.
Blood tests
These diagnose blood clotting problems, cholesterol levels, diabetes, and other stroke risk factors.
Cardiac monitoring
Heart tests like EKG and echocardiogram check for atrial fibrillation and other sources of clots.
Carotid ultrasound
This shows plaque buildup and blood flow in the major arteries that deliver blood to the brain.
Cerebral angiogram
Also called intra-arterial angiography, this invasive test uses an injected dye and x-rays to give highly detailed images of brain arteries. This test is done if other imaging is inconclusive.
How are TIAs treated?
Treatment focuses on preventing a subsequent stroke since the TIA itself does not cause permanent damage. You will likely need to take medications long term and make lifestyle changes.
Medications
Commonly prescribed drugs include:
– Aspirin or other antiplatelet – Prevents clot formation. Often given immediately in the ER.
– Anticoagulants – Blood thinners like heparin or warfarin stop existing clots from growing and prevent new ones.
– Statins – Lower cholesterol buildup in arteries.
– Angiotensin converting enzyme (ACE) inhibitors – Reduce high blood pressure.
– Diabetes drugs – Tight control of blood sugar may lower stroke risk.
Surgery
Procedures to improve blood flow and prevent stroke after a TIA include:
– Carotid endarterectomy – This removes fatty plaque buildup inside the carotid artery in the neck, which is a major supplier of blood to the brain. This is done if the blockage exceeds 70%.
– Angioplasty and stenting – A collapsed or narrowed artery is repaired by threading a tiny balloon to the site during angioplasty and inflating it to widen the artery. A wire mesh stent may be left in place.
– EC-IC bypass – This procedure reroutes blood flow from an external carotid artery to an internal carotid artery beyond the blocked area.
Lifestyle changes
Your doctors will recommend target levels and plans for:
– Controlling high blood pressure.
– Lowering high cholesterol through diet and possibly medications.
– Getting blood sugar under control if diabetic.
– Quitting smoking immediately.
– Beginning regular exercise appropriate for your condition.
– Losing weight if overweight or obese.
– Limiting alcohol and avoiding illegal drugs.
– Eating a heart-healthy diet focusing on fruits, vegetables, whole grains, lean proteins, low-fat dairy, nuts, legumes, foods high in omega 3 fatty acids (like fish, avocados, and olive oil), and minimized salt, sugar, and processed foods.
What is the long-term outlook after a TIA?
People who have a TIA can recover and maintain a good quality of life by following their treatment plan closely to reduce stroke risk. Keep all follow-up appointments with your doctor and take medications as directed.
Controlling underlying medical conditions and living a generally healthy lifestyle help prevent recurrent TIAs and strokes. Let your doctor know if you experience any new symptoms right away, as prompt care for TIAs and early strokes leads to the best outcomes.
Research shows that 90% of stroke risk can be eliminated by managing controllable factors like high blood pressure, diabetes, cholesterol levels, and not smoking.
While TIAs require quick action for evaluation and treatment, focusing on addressing the risk factors that caused yours and sticking to a prevention plan can allow you to reduce your risk and live well over the long term.
Conclusion
A TIA or minor stroke is a strong warning sign of an impending major stroke. Recognizing TIA symptoms like sudden trouble speaking, one-sided numbness or paralysis, vision issues, dizziness, and headache and seeking immediate emergency care is critical.
Though TIAs do not leave permanent damage, they require urgent diagnosis and treatment to uncover the cause and prevent a disabling stroke within days or weeks. Controlling medical conditions through medications and living a healthy lifestyle focused on ideal blood pressure, cholesterol, blood sugar, diet, exercise, and smoking cessation can significantly lower recurrent TIA and stroke risk long-term.