Transient ischaemic attack

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 National Clinical Guideline for Stroke was published in 2023 and made a number of updated recommendations, including the use of dual antiplatelet therapy (DAPT). It should be noted that DAPT is not currently recommended for 'major' ischaemic stroke as the risk of haemorrhagic transformation is too high.

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. REF

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

Clinical features

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

Assessment and referral

Patients with acute focal neurological symptoms that resolve completely within 24 hours of onset (i.e. suspected TIA) should:

• be given aspirin 300 mg immediately unless contraindicated
• assessed urgently within 24 hours by a stroke specialist clinician

Examples of TIA mimics that require exclusion

• hypoglycaemia
• intracranial haemorrhage
  • all patients on anticoagulants or with similar risk factors should be admitted for urgent imaging to exclude haemorrhage

If a patient presents more than 7 days ago they should be seen by a stroke specialist clinician as soon as possible within 7 days.

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.