Transient ischaemic attack

01OverviewDefinition, clinical context and the essential points that orientate the chapter.

TIA is a time-critical clinical diagnosis rather than a harmless mini-stroke. Symptoms have resolved by assessment, but the risk of completed stroke is front-loaded into the following hours and days. The history should reconstruct the exact onset, maximal deficit, progression, duration and recovery; establish whether symptoms were negative or positive; identify the vascular territory; and obtain a witness account. Acute focal loss of power, sensation, speech, vision or coordination is more persuasive than isolated faintness, confusion or generalised weakness.

Important mimics include migraine aura, focal seizure with post-ictal deficit, hypoglycaemia, syncope, peripheral vestibular disease, functional neurological disorder and peripheral nerve disease. Mimics should be recognised through positive evidence, not by assuming that young age, normal examination or a normal CT excludes ischaemia. Check capillary glucose promptly and treat any persisting or recurring focal deficit as stroke until assessed by an emergency stroke team.

Specialist assessment integrates brain imaging when useful, ECG and rhythm investigation, arterial imaging, vascular risk evaluation and selective cardiac testing. The specialist determines whether the event is genuinely ischaemic and chooses antiplatelet or anticoagulant therapy according to mechanism. A suspected cardioembolic event in atrial fibrillation does not justify combining aspirin and anticoagulation indefinitely, and a suspected carotid event should not wait behind a routine clinic queue.

Key points

A TIA is a transient focal neurological syndrome caused by cerebral, spinal or retinal ischaemia without acute infarction; the diagnosis remains clinical and retrospective rather than being proved by one normal scan.
Sudden negative symptoms such as unilateral weakness, language disturbance or monocular visual loss fit better than gradually spreading positive tingling, flashing lights or jerking, although atypical presentations still need expert assessment.
Treat suspected TIA as an urgent warning of stroke: give aspirin 300 mg immediately unless contraindicated and arrange specialist assessment within 24 hours under current NICE guidance.
Do not use ABCD2 or another prediction score to decide referral urgency; apparently low scores can coexist with atrial fibrillation, carotid stenosis or repeated events.
Persistent deficit, current recurrent symptoms, reduced consciousness or an uncertain last-known-well time belongs on the emergency acute-stroke pathway rather than the outpatient TIA route.
Routine CT brain is not recommended for every suspected TIA; use it when an alternative diagnosis is suspected, while specialist-directed MRI with diffusion-weighted imaging may demonstrate infarction or a competing lesion.
Carotid-territory symptoms require urgent carotid imaging if the person could be suitable for endarterectomy; benefit depends on symptom–artery concordance, stenosis measurement and timely intervention.
After specialist confirmation, define mechanism and begin secondary prevention addressing antithrombotic therapy, atrial fibrillation, lipids, blood pressure, diabetes, smoking and relevant carotid disease.

02AetiologyUnderlying causes, associations and risk factors, with why each one matters.

Large-artery atheroembolism

Carotid or vertebrobasilar plaque can shed platelet-rich emboli or transiently reduce flow to cerebral or retinal tissue.

Cardioembolism

Atrial fibrillation, intracardiac thrombus and valve disease can generate a brief occlusion that dissolves or migrates before infarction is demonstrated.

Small-vessel occlusion

Temporary blockage of a penetrating arteriole can produce a compact pure motor or sensory syndrome without cortical features.

Dissection and haemodynamic disease

Cervical dissection or critical arterial stenosis can cause embolic or low-flow episodes, especially with pain or reproducible perfusion stress.

03PathophysiologyThe causal sequence from the underlying abnormality to symptoms and harm.

1
Transient arterial obstruction
Thrombus, embolus or severe flow limitation abruptly reduces perfusion to a focal retinal, cerebral or spinal territory.
2
Reversible neuronal dysfunction
Energy delivery falls enough to stop normal signalling but recovers before irreversible tissue injury is demonstrable.
3
Clinical symptom resolution
Negative focal symptoms resolve as the clot fragments, moves or collateral flow improves, but disappearance does not identify the mechanism.
4
Persistent vascular instability
The source lesion often remains active, making TIA a warning of imminent completed infarction rather than a benign resolved event.

04Clinical features and red flagsSymptoms, examination findings, patterns of presentation and time-critical warnings.

Anterior circulation pattern

Contralateral face or limb weakness or sensory loss, dysphasia with dominant-hemisphere ischaemia, neglect with non-dominant involvement, or transient monocular blindness suggests carotid-territory disease.

Posterior circulation pattern

Sudden diplopia, dysarthria, limb or gait ataxia, hemianopia or crossed brainstem findings can represent vertebrobasilar ischaemia, especially when several focal symptoms occur together.

Crescendo events

Repeated stereotyped focal episodes over hours or days may signal unstable arterial disease and require emergency stroke-team discussion rather than serial routine referrals.

Migraine contrast

Aura often evolves over minutes with positive visual or sensory phenomena spreading between modalities, whereas TIA more often begins abruptly with maximal negative deficit, but overlap prevents diagnosis by one feature.

Seizure contrast

Witnessed tonic activity, automatisms, head turning, loss of awareness or post-event confusion supports seizure; Todd weakness may persist, so stroke assessment is still necessary when uncertainty remains.

Retinal ischaemia

A painless monocular curtain or shade is amaurosis fugax until assessed and carries the same need for urgent vascular and cardiac evaluation as a hemispheric TIA.

Red flags requiring action

Any neurological deficit still present, even if improving, requires emergency acute-stroke assessment and immediate brain imaging rather than a TIA clinic appointment.
Recurrent events during the same day, a fluctuating deficit or a suspected symptomatic high-grade carotid lesion needs urgent stroke-specialist escalation.
Thunderclap headache, meningism, anticoagulant-associated symptoms, head injury or reduced consciousness raises concern for haemorrhage or another emergency diagnosis.
New painful Horner syndrome, neck trauma or unilateral head and neck pain with focal symptoms suggests cervical artery dissection and warrants urgent angiographic imaging.
Transient monocular loss with jaw claudication, scalp tenderness or systemic inflammation in an older adult raises possible giant cell arteritis and threatens the other eye.

05InvestigationsWhat to request, why it matters and how to interpret it.

Investigation order

Read from the initial assessment onwards. Tests may run in parallel in urgent care; first-line, preferred, confirmatory, definitive and gold-standard labels appear only when the chapter explicitly states them.

01
Capillary blood glucoseFirst step
Why
Identify a rapidly reversible mimic during or immediately after the focal episode.
Interpretation and limitations
Correct hypoglycaemia promptly, but do not assume it explains a focal deficit if symptoms persist after glucose normalises or the history remains vascular.
02
Twelve-lead ECG and rhythm assessment
Why
Detect atrial fibrillation, recent myocardial disease or another cardiac clue that changes antithrombotic management.
Interpretation and limitations
A normal single ECG does not exclude paroxysmal atrial fibrillation; ambulatory monitoring duration should reflect the suspected mechanism and specialist plan.
03
Brain imaging
Why
Look for infarction or an alternative structural diagnosis when specialist assessment indicates imaging.
Interpretation and limitations
Routine CT is not necessary for all resolved suspected TIAs; MRI with diffusion-weighted sequences is more sensitive for small acute infarcts but a negative MRI cannot erase a convincing clinical event.
04
Carotid imaging
Why
Identify ipsilateral extracranial carotid stenosis after a retinal or hemispheric event in a potential surgical candidate.
Interpretation and limitations
Report the side and stenosis convention, and correlate anatomy with symptoms; urgent endarterectomy assessment is relevant for recently symptomatic 50–99% NASCET stenosis when clinically appropriate.
05
Baseline vascular blood profile
Why
Inform secondary prevention and expose mimics or treatment constraints.
Interpretation and limitations
Check full blood count, renal function, glucose or HbA1c and lipids; use coagulation testing selectively and interpret results alongside anticoagulant use and acute illness.
06
Echocardiography or extended cardiac investigation
Why
Search for a cardiac embolic source when the clinical and imaging phenotype makes the result actionable.
Interpretation and limitations
Do not request indiscriminately; select transthoracic, transoesophageal or shunt assessment with stroke and cardiology input according to age, infarct pattern and competing mechanisms.

06Differential diagnosisRealistic alternatives and the features that help distinguish them.

Migraine aura

Gradually spreading positive visual or sensory symptoms followed by headache favour aura, while abrupt negative loss fits ischaemia.

Focal seizure

Positive jerking, automatisms and postictal weakness support seizure; recurrent stereotyped speech or sensory events can remain difficult.

Hypoglycaemia

Low glucose can produce focal or global neurological dysfunction and should be checked promptly even when TIA remains possible.

Syncope or functional symptoms

Global presyncope suggests hypoperfusion, while positive inconsistency supports FND; neither usually maps cleanly to one arterial territory.

07ManagementImmediate care, first-line treatment, alternatives and escalation.

01NOWSuspected resolved TIAFirst stepA patient reports a sudden focal neurological or monocular visual deficit that has now completely resolved.

1Confirm that no deficit remains, record last-known-well and symptom chronology, check glucose and observations, and seek emergency help if symptoms recur during assessment.
2Give aspirin 300 mg immediately unless allergy, active bleeding, current anticoagulation or another important contraindication requires urgent specialist advice.
3Refer through the local TIA pathway for specialist assessment within 24 hours without using ABCD2 to postpone care.
4Give clear return instructions for recurrent weakness, speech or visual symptoms and advise against driving pending application of current DVLA rules and specialist guidance.

02PERSISTDeficit has not resolvedExamination or history shows ongoing, fluctuating or repeatedly recurring focal neurological impairment.

1Activate the emergency stroke pathway and document exact onset or last-known-well time, premorbid function, anticoagulants and recent bleeding or procedures.
2Arrange urgent brain and vascular imaging through the stroke service; do not give oral intake until swallowing has been screened.
3Let the specialist team assess reperfusion eligibility, blood-pressure priorities and antithrombotic timing rather than managing this as TIA.
4Reassess deterioration immediately for haemorrhage, oedema, seizure, aspiration, hypoglycaemia or another acute complication.

03MECHANISMSpecialist secondary preventionUrgent assessment concludes that the episode was a TIA or minor ischaemic cerebrovascular event.

1Review brain and arterial imaging, ECG and relevant cardiac testing to classify large-artery, cardioembolic, small-vessel or other likely mechanism.
2Select a guideline-concordant antiplatelet regimen for non-cardioembolic disease or anticoagulation for atrial fibrillation when safe; avoid unplanned overlap.
3Start intensive lipid lowering and individualised blood-pressure, diabetes, smoking, diet, weight and activity interventions.
4Complete urgent carotid surgical assessment where indicated and communicate the diagnosis, medicine plan and follow-up responsibility to primary care.

04MIMICAlternative diagnosis likelyAlternativeHistory supplies positive features for migraine, seizure, syncope or another non-ischaemic explanation.

1Describe the positive and negative diagnostic features rather than recording only that imaging was normal.
2Treat immediate hazards such as hypoglycaemia, arrhythmia or ongoing seizure and arrange the relevant urgent pathway when needed.
3Retain stroke-team input when focal deficit, vascular risk or uncertainty remains because mimics and ischaemia can coexist.
4Provide a concrete follow-up and safety-net plan; diagnostic uncertainty should not become loss to care.

Key medicines and prescribing safety3 treatments · regimens, roles and cautions

Reduces early recurrent ischaemic events while urgent specialist assessment determines the definitive mechanism and antithrombotic plan.

Aspirin

Give 300 mg orally once immediately for suspected TIA unless contraindicated, then continue 300 mg daily until specialist review under the local pathway.

Check active bleeding, severe allergy, anticoagulant use and alternative haemorrhagic diagnoses; do not delay emergency imaging when a deficit persists.

Provides ongoing platelet inhibition after confirmed non-cardioembolic TIA or ischaemic stroke when chosen by the specialist team.

Clopidogrel

For established long-term non-cardioembolic secondary prevention, 75 mg orally once daily is commonly selected after specialist confirmation; loading or dual therapy follows a stroke protocol.

Review bleeding, blood dyscrasia, planned procedures and concurrent anticoagulants; prolonged aspirin plus clopidogrel is not a default strategy.

Delivers high-intensity lipid lowering and reduces recurrent atherosclerotic cardiovascular events after confirmed TIA or stroke.

Atorvastatin

Offer 80 mg orally once daily for established cerebrovascular disease, using a lower dose when interactions, adverse-effect risk or patient preference make this appropriate.

Check baseline liver tests, pregnancy status, interacting medicines and unexplained muscle symptoms, then follow current NICE lipid targets and monitoring.

08ComplicationsImportant consequences, why they occur and why they matter clinically.

Completed ischaemic stroke

The same active embolic or stenotic source can produce permanent infarction, with risk concentrated early after the warning event.

Recurrent transient attacks

Repeated embolism or haemodynamic failure can cause crescendo symptoms and signal particularly unstable vascular disease before stroke.

Retinal and cognitive injury

Further events may cause permanent monocular visual loss, strategic infarction or cumulative small-vessel cognitive disability over time.

Antithrombotic and procedural harm

Prevention reduces recurrence but can cause bleeding or intervention complications when mechanism, anatomy and comorbidity are not individualised.

09Monitoring and follow-upTreatment response, safety checks and longer-term review.

Confirm that the 24-hour specialist assessment actually occurred and that the final diagnosis, antithrombotic choice and duration are visible across care settings.
Ask about recurrent focal symptoms at every early contact and direct any new episode to emergency stroke services rather than waiting for routine follow-up.
Monitor blood pressure, non-HDL cholesterol response, glycaemic status, smoking and medicine adherence as active secondary-prevention targets.
For anticoagulated atrial fibrillation, monitor renal function, haemoglobin, bleeding, interactions and dose appropriateness through a defined service.
After carotid intervention, follow neurological status, wound and blood pressure according to the vascular pathway and continue medical risk reduction.
Review driving, occupational hazards and recurrence safety advice using current DVLA standards and the individual clinical picture.

10Special situationsVariants, exceptions and circumstances that change the usual approach.

Resolved is not reassuring

The disappearance of symptoms defines the presentation but does not reduce the need for rapid action; early recurrent risk is the reason the pathway is urgent.

Positive versus negative

Loss of function favours ischaemia while spreading positive phenomena favour migraine or seizure, but the distinction informs probability rather than delivering a diagnosis alone.

MRI changes classification

Diffusion-positive symptoms that resolve clinically may be classified as a minor ischaemic stroke under a tissue-based definition and still require the same prevention work.

Territory guides anatomy

Monocular visual loss and aphasia point towards a carotid source, whereas diplopia with ataxia suggests posterior circulation disease and requires different arterial imaging attention.

A normal pulse misses AF

Paroxysmal atrial fibrillation can evade examination and a short ECG, so monitoring intensity should follow embolic suspicion rather than one rhythm snapshot.

Risk score is not triage

ABCD2 omits several dangerous mechanisms and should not be used to deny or delay the nationally recommended specialist timescale.

11Common pitfallsFrequent interpretation and management errors.

01
Do not discharge a patient with persisting weakness or dysphasia to await a TIA clinic because the symptoms seem mild or are improving.
02
Do not use a low ABCD2 score, young age or normal CT as evidence that urgent assessment is unnecessary.
03
Do not call isolated syncope, global confusion or chronic dizziness a TIA without identifying a plausible focal vascular syndrome.
04
Do not request routine CT as a substitute for a careful witness history and specialist assessment of resolved symptoms.
05
Do not prescribe indefinite dual antiplatelet therapy or combine an antiplatelet with anticoagulation without a specific, reviewed indication.
06
Do not overlook amaurosis fugax, posterior circulation symptoms or cervical dissection because FAST was negative.