Neurology: TIA & Stroke Flashcards
What is a TIA>
Is a transient (less than 24 hours, typically 30 minutes) period of neurological dysfunction without evidence of acute infarction.
A transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.
Risk factors for TIA?
- Diabetes mellitus
- High cholesterol
- HTN
- Smoking
- FH of CVS disease/stroke
- AF (for cardioembolic TIAs)
Clinical features of TIA?
Similar to stroke BUT completely resolves within 24 hours of onset.
- unilateral weakness or sensory loss.
- aphasia or dysarthria
- ataxia, vertigo, or loss of balance
- visual problems e.g. sudden transient loss of vision in one eye (amaurosis fugax), diplopia, homonymous hemianopia
Management of TIA?
1) Aspirin 300mg
2) Consider concurrent PPI use (anyone with dyspepsia)
3) Specialist assessment
What are 3 exceptions to giving 300mg aspirin immediately in TIA?
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
If a patient has a a bleeding disorder or is taking an anticoagulant and present with TIA/stroke symptoms, what should you do?
needs immediate admission for imaging to exclude a haemorrhage
Referral for patients who have had a suspected TIA in the last 7 days?
arrange urgent assessment (within 24 hours) by a specialist stroke physician
Referral for patients who have had a suspected TIA which occurred more than 7 days ago?
refer for specialist assessment as soon as possible within 7 days
Driving and TIA?
Advise the person not to drive until they have been seen by a specialist.
What imaging is indicated in a TIA?
MRI –> is preferred to determine the territory of ischaemia, or to detect haemorrhage or alternative pathologies
It should be done on the same day as the specialist assessment if possible
Investigations in TIA?
1) Neuroimaging: MRI
2) Carotid imaging: urgent carotid doppler
Why is carotid imaging important in TIA?
atherosclerosis in the carotid artery may be a source of emboli in some patients
When is a carotid doppler not indicated in TIA?
If they are not a candidate for carotid endarterectomy
2ary prevention following TIA?
1) antiplatelet therapy to follow on from initial aspirin therapy: clopidogrel
2) lipid modification: atorvastatin 20–80 mg daily
What is 1st line antiplatelet in 2ary prevention of TIA?
Clopidogrel
What can be given during 2ary prevention of TIA in patients who cannot tolerate clopidogrel?
aspirin + dipyridamole
What is the aim of statin therapy in 2ary prevention of TIA?
To reduce non-HDL cholesterol by more than 40%
What is a carotid artery endarterectomy?
a surgical procedure to remove a build-up of fatty deposits (plaque), which cause narrowing of a carotid artery.
When is a carotid artery endarterectomy recommended?
Recommend if the patient has suffered stroke or TIA in the carotid territory and is not severely disabled.
Should ONLY be considered if carotid stenosis >70%.
What is a stroke?
A sudden interruption in the vascular supply of the brain
Characterised by rapidly developing signs of focal or global disturbance of cerebral functions which lasts longer than 24 hours OR leads to death.
What are the 2 main types of stroke?
1) Ischaemic stroke (85%)
2) Haemorrhagic stroke (13%)
Mechanism of an ischaemic stroke?
Reduction or complete blockage of blood flow to part of the brain, resulting in tissue hypoperfusion
What are some causes of an ischaemic stroke?
1) Embolism (from elsewhere)
2) Thrombosis e.g. due to atherosclerotic plaque rupture within cerebral vessel
3) Small vessel disease e.g. chronic HTN nges in the small vessels of the brain
4) Cardioembolic e.g. in F
5) Systemic hypoperfusion e.g. cardiac arrest
6) Cerebral venous sinus thrombosis
How can chronic HTN lead to an ischaemic stroke?
Chronic hypertension causes changes in the small vessels of the brain. Middle layer of the vessel (tunica media) becomes enlarged and causes narrowing/occlusion of the vessels.