A transient ischemic attack (TIA), commonly known as mini-stroke, is a temporary, or transient, stroke with noticeable symptoms that end within 24 hours. A TIA causes the same symptoms of stroke, such as weakness or numbness on one side of the body, sudden dimming or loss of vision, difficulty speaking or understanding language, and slurred speech.
All forms of stroke, including a TIA, result from a disruption in blood flow to the central nervous system. A TIA is caused by a temporary disruption in blood flow to the brain, or cerebral blood flow (CBF). The primary difference between a major stroke and a TIA's minor stroke is how much tissue death (infarction) can be detected afterwards through medical imaging. While a TIA must by definition be associated with symptoms, strokes can also be asymptomatic or silent. In a silent stroke, also known as a silent cerebral infarct (SCI), there is permanent infarction detectable on imaging, but there are no immediately observable symptoms. The same person can have major strokes, minor strokes, and silent strokes, in any order.
The occurrence of a TIA is a risk factor for having a major stroke, and many people with TIA have a major stroke within 48 hours of the TIA. All forms of stroke are associated with increased risk of death or disability. Recognition that a TIA has occurred is an opportunity to start treatment, including medications and lifestyle changes, to prevent future strokes.
Signs and symptoms
Signs and symptoms of TIA are widely variable and can mimic other neurologic conditions, making the clinical context and physical exam crucial in ruling in or out the diagnosis. The most common presenting symptoms of TIA are focal neurologic deficits, which can include, but are not limited to:
- Amaurosis fugax (painless, temporary loss of vision)
- One-sided facial droop
- One-sided motor weakness
- Diplopia (double vision)
- Problems with balance and spatial orientation or dizziness
- Visual field deficits, such as homonymous hemianopsia or monocular blindness
- Sensory deficits in one or more limbs and of the face Below is a table of symptoms at presentation, and what percentage of the time they are seen in TIAs versus conditions that mimic TIA. In general, focal deficits make TIA more likely, but the absence of focal findings do not exclude the diagnosis, and further evaluation may be warranted if clinical suspicion for TIA is high (see "Diagnosis" section below).
TIA vis-à-vis mimics
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! Symptoms
Symptoms of TIAs can last on the order of minutes to one–two hours, but occasionally may last for a longer period of time. Importantly, patients with symptoms that last more than one hour are more likely to have permanent neurologic damage, making prompt diagnosis and treatment important to maximize recovery.
In-situ thrombosis, an obstruction that forms directly in the cerebral vasculature unlike the remote embolism previously mentioned, is another vascular occurrence with possible presentation as TIA. The modifiable risk factors are commonly targeted in treatment options to attempt to minimize risk of TIA and stroke. These tests help with screening for bleeding or hypercoagulable conditions. Other lab tests, such as a full hypercoagulable state workup or serum drug screening, should be considered based on the clinical situation and factors, such as the age of the patient and family history.
Vessels in the head and neck may also be evaluated to look for atherosclerotic lesions that may benefit from interventions, such as carotid endarterectomy. The vasculature can be evaluated through the following imaging modalities: magnetic resonance angiography (MRA), CT angiography (CTA), and carotid ultrasonography/transcranial doppler ultrasonography. Confirming a diagnosis of carotid artery stenosis is important because the treatment for this condition, carotid endarterectomy, can pose significant risk to the patient, including heart attacks and strokes after the procedure. These include:
- Avoiding smoking
- Cutting down on fats to help reduce the amount of plaque buildup
- Eating a healthy diet, including plenty of fruits and vegetables
- Limiting sodium in the diet, thereby reducing blood pressure
- Exercising regularly
- Moderating intake of alcohol, stimulants, sympathomimetics, etc.
- Maintaining a healthy weight
In addition, it is important to control any underlying medical conditions that may increase the risk of stroke or TIA, including: Therefore, management centers on the prevention of future ischemic strokes and addressing any modifiable risk factors. The optimal regimen depends on the underlying cause of the TIA.
Lifestyle modification
Lifestyle changes have not been shown to reduce the risk of stroke after TIA. While no studies have looked at the optimal diet for secondary prevention of stroke, some observational studies have shown that a Mediterranean diet can reduce stroke risk in patients without cerebrovascular disease. The clopidogrel can generally be stopped after 10 to 21 days.
The typical therapy may include aspirin alone, a combination of aspirin plus extended-release dipyridamole, or clopidogrel alone. Anticoagulant therapy can decrease the relative risk of ischemic stroke in those with atrial fibrillation by 67% Direct acting oral anticoagulants (DOACs), such as apixaban, are as effective as warfarin while also conferring a lower risk of bleeding. Generally, anticoagulants and antiplatelets are not used in combination, as they result in increased bleeding risk without a decrease in stroke risk. Blood pressure control is often achieved using diuretics or a combination of diuretics and angiotensin converter enzyme inhibitors, although the optimal treatment regimen depends on the individual. The effects achieved in stroke recurrence were mainly obtained through the ingestion of angiotensin-converting enzyme (ACE) inhibitor or a diuretic. While its role in stroke prevention is unclear, statin therapy has been shown to reduce all-cause mortality and may be recommended after TIA. However, data from 2017 suggests that metformin, pioglitazone and semaglutide may reduce stroke risk. For those with extra-cranial stenosis between 50 and 69%, carotid endarterectomy decreases the 5-year risk of ischemic stroke by about 16%. Following the procedure, there is no difference in effectiveness if you compare carotid endarterectomy and carotid stenting procedures, however, endarterectomy is often the procedure of choice as it is a safer procedure and is often effective in the longer term for preventing recurrent stroke. Treatment and preventative measures after a TIA (for example treating elevated blood pressure) can reduce the subsequent risk of an ischemic stroke by about 80%. The ABCD<sup>2</sup> score is no longer recommended for triage (to decide between outpatient management versus hospital admission) of those with a suspected TIA due to these limitations.