Transient ischaemic attack (N) Flashcards
Define transient ischaemic attack.
Temporary, focal cerebral ischaemia that results in reversible neurological deficits without acute infarction that resolves completely within 24h
What demographics does transient ischaemic attack happen in commonly? (2)
- M>F
- incidence increases with age
What are some risk factors for transient ischaemic attack? (7)
- AF (most common)
- valvular disease
- carotid stenosis
- congestive heart failure
- hypertension
- DM
- smoking
What are transient ischaemic attack usually?
Usually embolic, may be thrombotic
What are some causes of transient ischaemic attack? (3)
- carotid atherosclerosis
- cardioembolism - mural thromboembolism post-MI/AF, mitral valve disease, atrial myxoma, prosthetic valve
- clots from right side of circulation can cause stroke if there is a septal defect (PFO)
If there is infarction on imaging in suspected transient ischaemic attack, what does this suggest?
If infarction on imaging, stroke NOT transient ischaemic attack
When should we suspect TIA?
In anyone with sudden-onset focal neurological deficit that has completely resolved within 24h and cannot be explained by another condition e.g. hypoglycaemia
How long do TIAs usually last?
10-15 minutes, but can be anywhere from a few minutes to 24h
What are the main clinical features of TIA? (6)
- sudden-onset and brief duration of Sx (most resolve within 1h)
- unilateral weakness or paralysis
- dysphasia (left-sided ischaemia)
- ataxia, vertigo or loss of balance (posterior TIA)
- homonymous hemianopia
- diplopia
What are the features of an anterior TIA (carotid territory)? (5)
- unilateral
- most often affect the motor area - weakness in arm, leg or one side of face
- dysarthria
- Broca’s dysphasia (if LHS)
- amaurosis fugax (painless fleeting loss of vision caused by retinal ischaemia)
What are the features of a posterior TIA (vertebrobasilar territory)? (4)
- homonymous hemianopia (if ophthalmic cortex involved)
- may have bilateral vision impairment
- may be hemiparesis, hemisensory Sx, diplopia, vertigo, vomiting, dysarthria, dysphagia or ataxia
- ask about unilateral weakness, facial drooping, gait disturbance, confusion, memory loss, dysarthria or abnormal behaviour
What does dysphasia indicate in TIA?
Left-sided ischaemia
What does ataxia, vertigo or loss of balance indicate in TIA?
Posterior TIA (vertebrobasilar territory)
What might you check for on examination in TIA? (2)
- check pulse for AF
- auscultate carotids for bruits (carotid atherosclerosis)
What investigation do we order for all patients with TIA?
Urgent carotid doppler
What scans can we do for TIA? (3)
- CT head - urgently needed if patient has bleeding disorder or is on anticoagulation to exclude haemorrhage
- MRI brain with diffusion-weighted imaging - to determine location
- ECG - evaluate for AF and rule out myocardial ischaemia
If there is infarction on imaging, what does this suggest in suspected TIA?
If infarction of imaging –> STROKE not TIA
What bloods can we do for TIA and why? (2)
- blood glucose - exclude hypoglycaemia as cause of sudden neurological Sx
- PT, APTT, INR - exclude coagulopathy
What score do we calculate in TIA and why?
ABCD2 score - estimates future stroke risk in TIA patients
When is stroke risk highest after TIA?
In first 7 days following TIA –> start secondary prevention therapy immediately once TIA confirmed
What are some differential diagnoses for TIA? (9)
- stroke (>24h)
- hypoglycaemia (BGC<3.3mmol/mol)
- seizure with post-seizure paralysis
- complex migraine
- space occupying lesion (intracranial haemorrhage, abscess or mass)
- labyrinthine disorders (BPPV, Meniere’s, labyrinthitis)
- MS
- peripheral neuropathy (Bell’s palsy non-forehead sparing, Ramsay-Hunt may show vesicles near tympanic membrane)
- global hypoperfusion/syncope
How do we manage patients with acute neurological symptoms that resolve completely within 24 hours?
300mg aspirin immediately + urgent assessment within 24h
What do we do in suspected TIA if patient is on anticoagulant, or has a bleeding disorder?
Urgent CT head to rule out haemorrhage
What is the gold standard treatment for TIA?
- dual antiplatelet therapy (followed by clopidogrel for life):
- aspirin 300mg loading dose, followed by 75mg for 21d
- clopidogrel 300mg loading dose, followed by 75mg for 21d
- then clopidogrel 75mg for life
- high-intensity statin therapy (atorvastatin 20-80mg)
When do we treat BP in TIA?
Only if >220/120 or other indication
What do we do if patients with TIA present within vs after 7 days of episode?
- within 7d: specialist review within 24h
- after 7d: specialist review within 7d
What antiplatelet therapy do we provide in TIA (gold standard)?
Dual antiplatelet therapy for 21d, followed by clopidogrel monotherapy for life
- aspirin 300mg loading dose –> 75mg for 21 days
- clopidogrel 300mg loading dose –> 75mg for 21 days
- clopidogrel 75mg monotherapy for life
What medication can be used for secondary long-term prevention of TIA?
Atorvastatin 80mg + antihypertensives
What if a patient with TIA has carotid artery stenosis?
Carotid endarterectomy (if carotid artery stenosis >70%)
In AF patients with TIA, what anticoagulant do we give?
DOAC or LMWH
What do we give for TIA with cardiac emboli present?
Warfarin
What can patients not do for at least 1 month after TIA?
Drive
When is stroke risk highest post-TIA?
Risk of recurrent stroke is high in the first 7 days following a TIA –> start secondary prevention therapy (dual antiplatelet + statin) immediately
What are some complications of TIA? (2)
- stroke
- MI
Describe the prognosis of TIA.
By definition, a patient with a TIA has no residual symptoms from the primary event; however patients have increased risk of future ischaemic stroke
