A transient ischaemic attack (TIA), as the name suggests, is a brief period of neurological deficit due to a vascular cause, typically lasting less than an hour.

The original definition of a TIA was time-based: a sudden onset of a focal neurologic symptom and/or sign lasting less than 24 hours, brought on by a transient decrease in blood flow. However, this has now changed as it is recognised that even short periods of ischaemia can result in pathological changes to the brain. Therefore, a new 'tissue-based' definition is now used: a transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction. #link13

Patients often use the term 'mini-stroke' for TIAs.

The clinical features are similar to those of a stroke, i.e. sudden onset, focal neurological deficit but, rather than persisting, the features resolve, typically within 1 hour.

Possible features include

• unilateral weakness or sensory loss.
• aphasia or dysarthria
• ataxia, vertigo, or loss of balance
• visual problems
  • sudden transient loss of vision in one eye (amaurosis fugax)
  • diplopia
  • homonymous hemianopia

Neuroimaging #link15

• NICE recommend that CT brains should not be done 'unless there is clinical suspicion of an alternative diagnosis that CT could detect'
• MRI (including diffusion-weighted and blood-sensitive sequences) is preferred to determine the territory of ischaemia, or to detect haemorrhage or alternative pathologies
  • it should be done on the same day as the specialist assessment if possible

Carotid imaging

• atherosclerosis in the carotid artery may be a source of emboli in some patients
• all patients should therefore have an urgent carotid doppler unless they are not a candidate for carotid endarterectomy

The ABCD2 prognostic score has previously been used to risk stratify patients who present with a suspected TIA. However, data from studies have suggested it performs poorly and it is therefore no longer recommended by NICE Clinical Knowledge Summaries. Instead, NICE recommend:

Immediate antithrombotic therapy: #link14

• give aspirin 300 mg immediately, unless:
  • 1. the patient has a bleeding disorder or is taking an anticoagulant (needs immediate admission for imaging to exclude a haemorrhage)
  • 2. the patient is already taking low-dose aspirin regularly: continue the current dose of aspirin until reviewed by a specialist
  • 3. Aspirin is contraindicated: discuss management urgently with the specialist team

Specialist review

• if the patient has had more than 1 TIA ('crescendo TIA') or has a suspected cardioembolic source or severe carotid stenosis:
  • discuss the need for admission or observation urgently with a stroke specialist
• If the patient has had a suspected TIA in the last 7 days:
  • arrange urgent assessment (within 24 hours) by a specialist stroke physician
• if the patient has had a suspected TIA which occurred more than a week previously:
  • refer for specialist assessment as soon as possible within 7 days

Advise the person not to drive until they have been seen by a specialist.

Further management

Secondary prevention #link16

• antiplatelet therapy to follow on from initial aspirin therapy
  • clopidogrel is recommended first-line (as for patients who've had a stroke)
  • aspirin + dipyridamole should be given to patients who cannot tolerate clopidogrel
• lipid modification
  • high-intensity statin (such as atorvastatin 20–80 mg daily) - the aim of statin therapy is to reduce non-HDL cholesterol by more than 40%

With regards to carotid artery endarterectomy: #link17

• recommend if the patient has suffered stroke or TIA in the carotid territory and is not severely disabled
• should only be considered if
  • carotid stenosis > 70% according European Carotid Surgery Trialists' Collaborative Group criteria or
  • > 50% according to North American Symptomatic Carotid Endarterectomy Trial criteria