8th August 2024

Transient ischaemic attack (TIA)

TIA

TIA is defined as a transient episode of focal neurological dysfunction due to ischaemia without acute infarction; aetiology is as per ischaemic stroke. It resolves within 24 hours and cannot be explained by other causes.

TIAs present with the same clinical features as stroke, depending on which vascular territory is affected, including speech or visual impairment and sensory or motor deficit. History (by the patient or a witness) is key to diagnosis.

Assessment and management of TIA

TIA is an emergency due to the high risk of stroke, however many patients can be managed as outpatients:

Admission should be considered if a patient has high risk features such as crescendo TIA (>1 TIA in a week), high risk of a cardioembolic source (new AF) or ongoing neurological symptoms (potential stroke).

Investigations should include:

• Routine bloods including clotting, blood sugar level to exclude mimic, ECG to exclude arrhythmia
• CT head is only recommended if an alternative cause is suspected or to exclude haemorrhage in patients taking anticoagulants
• Further investigations will be requested from TIA clinic:
  • MRI scan: if DWI demonstrates an acute infarct, the diagnosis is stroke
  • Consideration of carotid Doppler, echo and 24 hour tape as per ischaemic stroke

Management is as follows:

• Immediate treatment: on suspicion of TIA, give 300 mg aspirin (unless haemorrhage suspected)
• Secondary prevention:
  • Antiplatelet or anticoagulant: clopidogrel monotherapy lifelong or anticoagulation if in AF
  • High-intensity statin therapy
  • Carotid endarterectomy if significant stenosis on symptomatic side (as per stroke)
  • Control of vascular risk factors: diabetes, hypertension, smoking

TIA mimics

Important differentials to consider include: stroke, hypoglycaemia, migraine, seizure and postictal state, conversion disorders, malignancy, sepsis, multiple sclerosis, vasculitis, transient global amnesia and differentials of vertigo as previously discussed.

References

• Jones M, Power R. Transient ischaemic attack. In: BMJ Best Practice. [Internet]. London: BMJ Publishing Group, 2021 [July 13 2021; cited January 21 2022]. Available from: https://bestpractice.bmj.com/topics/en-gb/3000090
• Logmore M, Wilkinson I, Baldwin A, Wallin E. Oxford Handbook of Clinical Medicine. 9th edition. Oxford: Oxford University Press. 2014
• National Institute for Health and Care Excellence. Stroke and transient ischaemic attack in over 16s: diagnosis and initial management. London: NICE, 2019 [May 1 2019; cited January 21 2022]. Available from: https://www.nice.org.uk/guidance/ng128