Transient Ischaemic Attack

Question 1

Describe TIA

Answer 1

Rapid transient neurological deficit from cerebrovascular insult that involves ischaemia of the brain tissue without infarction –this replaces the old definition that a TIA resolves within 24 hours from the onset

Question 2

What are the causes/risk factors of TIA?

Answer 2

• Artheroembolism from carotid arteries
• Embolism from the heart
• Small vessel occlusin
• Hyperviscosity e.g. polycythaemia and sickle cell anaemia
• Vasculitides
• Idiopathic

*Same risk factors as stroke

Question 3

What are the signs and symptoms of TIA?

Answer 3

same as stroke but resolve within 24 hours (typically 1 hour)

Question 4

What investigations are carried out for TIA?

Answer 4

• FBC - elevated WBC count can suggest infection as a cause of symptoms.
- Profound anaemia can cause weakness, but usually this would be generalised.
- Polycythaemia, extreme thrombocytosis, or extremely high WBC count can contribute to risk of poor cerebral perfusion.
- Thrombocytopaenia means thrombolysis is contraindicated if a stroke occurs.
• Blood Glucose - hypoglycaemic events can give global symptoms such as confusion or syncope, but can also lead to focal symptoms and needs to be ruled out as a mimic of TIA.
• U&Es - electrolyte imbalances may give neurological symptoms that mimic TIA.
• Clotting Screen - this is used if the neurological deficit is still present at time of presentation, there is reason to suspect abnormal coagulation and thrombolytic therapy for stroke is being considered.
• Lipids - dyslipidaemia
• ESR - may indicate vasculitides if elevated.
• ECG - may show AF
• Echo - may show clots, valvular diseases and shunts.
• CT - often normal
• MRI - if positive, MRI can localise infarct, suggest aetiology, and distinguish TIA from stroke.
• Carotid Doppler - may show stenosis.
• CT Angiography - may show stenosis.

Question 5

What is the management of TIA?

Answer 5

• Time to intervention is crucial. Risk of stroke within 90 days of TIA is 2% in those treated within 72 hours of TIA, compared to 10% in those treated by 3 weeks.
• Control cardiovascular risk factors:
- BP (aim for <140/85mmHg,)
- Dyslipidaemia
- DM
- Smoking Cessation
• Antiplatelet drugs: Clopidogrel or low-dose aspirin with dipyridamole if CI
• Warfarin indications: Cardiac emboli (e.g. AF, mitral stenosis, recent big septal MI).
• Carotid endarterectomy if >70% stenosis at the origin of the internal carotid artery and operative risk is good. Surgery should be performed within 2 weeks of presentation.
• Operating on 50-70% stenoses may be valuable if the team’s perioperative stroke and mortality rate <3%.
• Endovascular carotid artery stenting is an alternative if not suitable for surgery, but safety and long-term benefits (instent restenosis is common) remain under investigation.

Driving: Avoid for 1 month; patients in the UK should inform the DVLA only if multiple attacks in short period or residual deficit

Question 6

What are the complications of TIA?

Answer 6

• stroke
• MI
• complications of stroke