Transient Ischaemic Attack (TIA)
A transient ischaemic attack (TIA) is defined as an acute loss of focal cerebral or ocular function with symptoms lasting less than 24 hours.
This updated UKMLA guide to ischaemic stroke is based on National Clinical Guideline for Stroke and NICE NG128, which covers guidelines on initial assessment, investigations, and management.
Note on TIA definition:
- Traditional teaching and UK guidance, including NICE, NICE CKS and the UK National Clinical Guideline for Stroke 2023, define stroke and TIA using the 24-hour clinical cut-off
- However, some modern definitions, particularly from the AHA/ASA, use a tissue-based definition
- Under this definition, TIA refers to a transient focal neurological deficit caused by ischaemia without evidence of acute infarction
- Therefore, if symptoms fully resolve but imaging shows acute infarction, the event is classified as an ischaemic stroke rather than a TIA
This is included because one may encounter both definitions in clinical practice and in different guideline sources.
Causes and Clinical Features
TIA is a transient, ischaemic stroke-like event and an important warning sign for future ischaemic stroke
- It shares similar risk factors and clinical features with ischaemic stroke, i.e. sudden-onset focal neurological deficits that are typically painless
- The key distinction is that TIA symptoms are temporary and fully resolve within 24 hours
- For a more detailed explanation of clinical features and vascular territory patterns, see the Stroke (Overview) article
Amaurosis fugax is a transient monocular visual loss caused by temporary ischaemia of the retina or optic nerve. It can be considered a form of TIA affecting the eye and is commonly associated with carotid artery disease.
Assessment and Management
Primary Care / Emergency Department
Immediate steps if TIA is suspected:
- Exclude hypoglycaemia
- Offer aspirin 300 mg immediately unless contraindicated (e.g. allergy, patients on anticoagulants)
- Refer within 24 hours to a stroke specialist clinician (acute stroke unit or neurovascular clinic)
Risk stratification tools (e.g. ABCD2 score) are NOT recommended to determine how urgently a patient needs to be referred or seen.
Due to the substantial risk of a completed stroke in the first few days following a TIA, all cases must be treated as urgent and assessed within that 24-hour window.
Secondary Care – Investigations
Imaging to be considered in secondary care:
| Imaging | Indications |
|---|---|
| Non-contrast CT head | ALL patients who take anticoagulants or have a bleeding disorder → urgent non-contrast CT head to exclude intracranial haemorrhage
Otherwise, it should NOT be performed routinely unless there is clinical suspicion of an alternative diagnosis that CT could detect This contrasts with the approach in suspected stroke, where non-contrast CT head is done in ALL patients urgently |
| MRI head | Primary imaging modality to detect ischaemia and support the diagnosis of TIA.
Indicated when the specialist determines the results will influence management, such as reducing diagnostic uncertainty or confirming the vascular territory of the stroke before starting dual antiplatelet therapy or planning carotid surgery |
| Carotid imaging (duplex ultrasound, CT / MR angiogram) | Indicated urgently (within 24 hours of specialist assessment) for patients who have anterior circulation symptoms and are considered potential candidates for carotid surgery |
| Investigation | Description / indications |
|---|---|
| Cardiac monitoring | Baseline ECG – all patients
Anyone with a suspected TIA or ischaemic stroke who is not already diagnosed with atrial fibrillation or atrial flutter should undergo cardiac monitoring (Holter or inpatient telemetry) for at least 24 hours |
| Transhythoracic echocardiogram | Indicated if:
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| Blood tests |
If the patient is young or the underlying cause remains unknown, consider targeted screening of:
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Secondary Care – Management
1. Antithrombotic Therapy
Every patient with TIA needs some form of antithrombotic therapy to prevent further cerebrovascular events, but the choice depends on whether the patient has atrial fibrillation or not.
TIA With No Atrial Fibrillation
Antiplatelets are the choice of antithrombotic therapy in the absence of AF (i.e., for thrombotic TIA)
There are 2 regimens recommended, depending on the patient’s bleeding risk.
| Bleeding risk | Antiplatelet regimen |
|---|---|
| Low bleeding risk (most cases) |
An alternative to clopidogrel is ticagrelor (loading dose: 180 mg, maintenance dose: 90 mg BD) Logistics regarding phase 1: When the patient is being reviewed by a specialist (within 24 hours), they would already have received a loading dose of aspirin 300 mg. The specialist would then just add the second antiplatelet agent to complete the DAPT (without repeating the initial aspirin dosing). Note that in a non-specialist setting, only aspirin should be given. DAPT should only be given by a specialist. |
| High bleeding risk |
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Note that DAPT is used in TIA but not in ischaemic stroke. This is due to the higher risk of haemorrhagic transformation in ischaemic stroke, which outweighs the potential benefits of DAPT.
Rationale in TIA: patients who experienced a TIA are at a substantial risk of further vascular events, and this risk is highest in the first few days. Large trials have demonstrated that early DAPT immediately after symptom onset (for 21 days) significantly reduces the rate of recurrent ischaemic strokes compared to using aspirin alone.
TIA With Atrial Fibrillation
Offer a non-contrast CT head to exclude intracerebral haemorrhage, then offer anticoagulation
- 1st line for most patients: DOAC (e.g. apixaban, rivaroxaban)
- 1st line in valvular AF: warfarin
Note the timing to start anticoagulation in TIA is different from that in ischaemic stroke:
- In ischaemic stroke with AF (i.e. embolic stroke), anticoagulation is only started after 5-14 days, with only aspirin 300 mg being given during those 5-14 days
- In TIA with AF (i.e. embolic TIA), anticoagulation can be started immediately, once intracerebral haemorrhage has been excluded
This difference in timing reflects the balance of benefits and bleeding risk in the presence of established infarction (stroke) vs TIA. Anticoagulants carry a much higher risk of intracerebral haemorrhage than antiplatelets.
- In ischaemic stroke with AF, there is a significant risk of haemorrhagic transformation in the infarcted brain tissue if anticoagulation is started immediately. Therefore, anticoagulation is typically delayed for about 5-14 days, while aspirin 300 mg is given in this period to prevent early recurrent ischaemia.
- In TIA with AF, there is no established infarcted tissue and thus essentially no risk of haemorrhagic transformation. Once intracerebral haemorrhage is excluded by imaging, anticoagulation can be started immediately to provide early secondary stroke prevention.
But ultimately, for both ischaemic stroke and TIA patients with AF, long-term anticoagulation (not antiplatelet therapy) is required for effective stroke prevention.
2. Other Secondary Prevention Strategies
All patients should receive the following:
- Lifestyle advice (e.g. healthy diet, regular physical activity, smoking cessation, reduce alcohol intake)
- High-intensity statin (usually atorvastatin 80 mg)
- Optimise blood pressure control as per the Hypertension (Primary) article
3. Carotid Intervention
Do NOT routinely offer carotid intervention to all patients with TIA.
Indications for carotid intervention depend on the severity of stenosis (reported with the NASCET method):
| Stenosis severity | Management |
|---|---|
| Severe stenosis (50-99%) | Perform carotid endarterectomy (on the problematic side only) within 7 days
If unfit for surgery → consider carotid angioplasty and stenting |
| Mild / moderate stenosis (<50%) | NO intervention is necessary |
DVLA Guidelines
Driving and TIA
After a stroke / TIA → always stop driving immediately.
Further action depends on the licence type:
| Licence type | Recommendation |
|---|---|
| Group 1 vehicle (car / motorcycle) |
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| Group 2 vehicle (bus / coach / lorry) |
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