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.
How can cardiac arrest lead to ischaemic stroke?
Systemic hypoperfusion –> supply to entire brain is reduced 2ary to systemic hypotension e.g. cardiac arrest
Mechanism of a haemorrahge stroke?
Occur 2ary to rupture of a blood vessel (usually arterioles and small arteries) or abnormal vascular structure within the brain.
Causes of a haemorrhagic stroke?
1) HTN
2) Trauma
3) Bleeding disorders
4) Anticoagulation
5) Age
6) Vascular malformations
7) Illicit drug use
Most important risk factor of a haemorrhagic stroke?
HTN
What are the 2 types of haemorrhagic stroke?
1) Intracerebral haemorrhage
2) Subarachnoid haemorrhage
What are the 2 main subtypes of ischaemic strokes?
1) Thrombotic stroke
2) Embolic stroke (can be blood clot, fat, air, or clumps of bacteria)
What is an important cause of embolic stroke?
AF
Is smoking a risk factor for haemorrhagic or ischaemic stroke?
Ischaemic
What is an intracerebral haemorrhage?
Bleeding into brain tissue 2ary to ruptured blood vessel (intraparenchymal and/or intraventricular)
Causes of intracerebral haemorrhage?
1) Spontaneous
2) Result of bleeding into an ischaemic infarct
3) Tumour
4) Rupture of aneurysm
What is a subarachnoid haemorrhage (SAH)?
bleeding outside of brain tissue between pia mater and arachnoid mater
Causes of an SAH?
1) rupture of intracranial saccular aneurysm
2) anticoagulants
3) arterial dissections etc
What is a silent stroke?
radiological or pathological evidence of an infarction or haemorrhage not caused by trauma that doesn’t cause any noticeable symptoms
Features of a stroke?
A sudden onset of neurological symptoms suggests a vascular cause (e.g., stroke). Stroke symptoms are typically asymmetrical.
1) Limb weakness
2) Facial weakness
3) Dysphasia (speech disturbance)
4) Visual field defects (homonymous hemianopia)
5) Sensory loss
6) Ataxia and vertigo (posterior circulation infarction)
What symptoms may be seen in cerebral hemisphere infarcts?
1) contralateral hemiplegia: initially flaccid then spastic
2) contralateral sensory loss
3) homonymous hemianopia
4) dysphasia
What features may be seen in a brainstem infarction?
may result in more severe symptoms including quadriplegia and lock-in-syndrome
What are lacunar infarcts?
Lacunar infarcts are small (2 to 15 mm in diameter) noncortical infarcts caused by occlusion of a single penetrating branch of a large cerebral artery.
These are small infarcts around the basal ganglia, internal capsule, thalamus and pons.
What features may be seen in lacunar infarcts?
this may result in pure motor, pure sensory, mixed motor and sensory signs or ataxia
What is the leading cause of death and disability?
Stroke
Give some complications of a stroke
- Infection – hospital acquired and aspiration pneumonia
- Pressure sores
- Neurological problems e.g. seizures, delirium, cerebral oedema
- VTE
- Death
- Cardiac complications (due to shared aetiology)
- Depression & anxiety
- Mobility problems; hemiparesis, hemiplegia, ataxia, falls, spasticity & contractures, difficulty with activities of daily living
- Sensory problems; touch, temperature, pain
- Continence problems
- Fatigue
- Communication difficulties, difficulties with activities of daily living, mobility problems
- Sexual dysfunction
- Visual problems
The combined contraceptive pill carries a tiny increased risk of stroke.
Who is this risk higher in?
1) patients with migraines with aura
2) smokers over 34 years
3) those with a history of stroke or TIA.
Imaging investigation of choice in stroke?
Diffusion-weighted MRI scan
What classification is used in stroke?
Oxford Stroke Classification (also known as the Bamford Classification).
This classifies strokes based on the initial symptoms.
What criteria is assessed in the Oxford Stroke Classification?
1) unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
2) homonymous hemianopia
3) higher cognitive dysfunction e.g. dysphasia
What arteries are involved in a total anterior circulation infarct?
Middle and anterior cerebral arteries
What criteria from the Oxford Stroke Classification are present in a total anterior circulation infarct?
All 3 criteria
What arteries are involved in a partial anterior circulation infarct?
involves the anterior OR middle cerebral artery on the affected side.
What criteria from the Oxford Stroke Classification are present in a partial anterior circulation infarct?
2 of the criteria
OR
Higher cerebral dysfunction alone
What arteries are involved in a lacunar infarct?
involves perforating arteries around the internal capsule, thalamus and basal ganglia
How does a lacunar infarct present?
Presents with 1 of the following:
1) unilateral weakness (and/or sensory deficit) of face and arm, arm and leg or all three.
2) pure sensory stroke.
3) ataxic hemiparesis
What arteries are involved in a posterior circulation infarct?
involves vertebrobasilar arteries
Presentation of a posterior circulation infarct?
presents with 1 of the following:
- cerebellar or brainstem syndromes
- loss of consciousness
- isolated homonymous hemianopia
Is a decrease in the level of consciousness more common in haemorrhagic or ischaemic strokes?
Haemorrhagic