Introduction

The original definition of a transient ischaemic attack (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.

Epidemiology

  • Incidence: 230.00 cases per 100,000 person-years
  • Peak incidence: 70+ years
  • Sex ratio: more common in males 1.3:1
<1 1-5 6+ 16+ 30+ 40+ 50+ 60+ 70+ 80+

Clinical features

Symptoms
  • Limb weakness (unilateral) (70%)
  • Dysphasia (50%)
  • Facial weakness (50%)
  • Visual field loss (20%): Amaurosis fugax (fleeting loss of vision) usually occurs to due ipsilateral carotid artery disease.
  • Double vision (5%): Double vision may occur for TIAs in the vertebrobasilar territory
  • Nausea & vomiting (5%): Nausea & vomiting may occur for TIAs in the vertebrobasilar territory
  • Vertigo (5%): Vertigo may occur for TIAs in the vertebrobasilar territory
Signs
  • Ataxia (5%): Ataxia may occur for TIAs in the vertebrobasilar territory

Management

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:
  • 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

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

Antithrombotic 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
  • these recommendations follow the 2012 Royal College of Physicians National clinical guideline for stroke. Please see the link for more details (section 5.5)
  • these guidelines may change following the CHANCE study (NEJM 2013;369:11). This study looked at giving high-risk TIA patients aspirin + clopidogrel for the first 90 days compared to aspirin alone. 11.7% of aspirin only patients had a stroke over 90 days compared to 8.2% of dual antiplatelet patients

With regards to carotid artery endarterectomy:
  • recommend if patient has suffered stroke or TIA in the carotid territory and are not severely disabled
  • should only be considered if carotid stenosis > 70% according ECST* criteria or > 50% according to NASCET** criteria

*European Carotid Surgery Trialists' Collaborative Group
**North American Symptomatic Carotid Endarterectomy Trial