Stroke And TIA Flashcards
What is a cerebrovascular accident (aka stroke)
sudden onset neurological symptoms caused by interruption in the vascular supply of the brain
State the 2 types of stroke and how common each are
- Ischaemic - 80%
- Haemorrhagic - 20%
What is an ischaemic stroke
decrease in blood flow due to arterial occlusion/stenosis
Give 3 causes of an ischaemic stroke
- thrombosis
- embolus
- Plaque
Give 5 RFs of an ischaemic stroke
- HTN
- Smoking
- T2DM
- Atrial fibrillation
- TIA
What are total anterior circulation infarcts and how do they present
- involves middle and anterior cerebral arteries
Presents with all 3 of the following:
1. contralateral hemiparesis and/or hemisensory loss of the face, arm & leg
2. homonymous hemianopia
3. higher cognitive dysfunction e.g. dysphasia, apraxia, agnosia
What are partial anterior circulation infarcts and how do they present
- involves smaller arteries of anterior circulation
- Presents with 2 of the following
1. unilateral hemiparesis and/or hemisensory loss of the face, arm & leg
2. homonymous hemianopia
3. higher cognitive dysfunction e.g. dysphasia, visuospatial disorder
How would a stroke in the anterior cerebral artery present
- Contralateral hemiparesis and sensory loss
- Lower limbs more affected than upper limbs
How would a stroke affecting the middle cerebral artery present
- Aphasia/ dysphasia
- Contralateral hemiparesis and sensory loss
- Upper limbs> lower limbs
- Contralateral homonymous hemianopia
What are lacunar infarcts and how would they present
- involves perforating arteries around the internal capsule, thalamus and basal ganglia
- presents with 1 of the following:
1. clumsy hand and dysarthria
2. pure hemisensory stroke
3. pure motor hemiparesis
4. sensori-motor stroke
5. ataxic hemiparesis
What are posterior circulation infarcts and how do they present
- involves vertebrobasilar arteries
- presents with 1 of the following:
1. cerebellar dysfunction - DANISH
2. loss of conscioussness/ sleepiness (reduced GCS)
3. isolated homonymous hemianopia
4. Brainstem: bilateral sensory/motor deficit
5. ipsilateral CN palsy and contralateral limb weakness
How would a stroke affecting the posterior cerebral artery present
- Vision loss - contralateral homonymous hemianopia
- macular sparing
- visual agnosia - impairment in recognition of visually presented items
How would a vertebrobasilar artery stroke present
- Cerebellar signs (Vanished)
- reduced consciousness
- balance disorders
How are ischaemic strokes diagnosed
- Non contrast CT head
- glucose and electrolytes
- CT angiography - for candidates for thrombectomy
What would you expect to see on a non contrast CT of someone who has had an ischaemic stroke
- immediate: brightness in artery indicates clot within lumen
- Late: darkness of brain parenchyma, loss of grey matter-white matter differentiation
Why are serum electrolytes and glucose investigated for ischaemic strokes
To exclude stroke mimics such as hypoglycaemia and hyponatraemia
How is an ischaemic stroke treated
- <4.5h since Sx onset + haemorrhage excluded = thrombolysis (IV alteplase) + thrombectomy
- 300mg oral/ rectal aspirin should be given ASAP if haemorrhagic stroke has been excluded
- Maintain glucose, oxygen and hydration
- HTN should not be treated in the initial period following a stroke (unless prior to thrombolysis)
What is the standard target treatment time for thrombolysis in acute ischaemic stroke
- within 4.5 hours of symptom onset
- within 9 hours of onset (or midpoint of sleep in ‘wake up’ stroke) if there’s salvageable brain tissue on MRI/ CT perfusion imaging
What is the standard target treatment time for thrombectomy in acute ischaemic stroke
- within 6 hours of symptom onset
- within 24 hours post-stroke onset if imaging shows salvageable brain tissue
Give 4 absolute contraindications to thrombolysis
- Uncontrolled hypertension >200/120mmHg
- intracranial neoplasm
- stroke < 3 months
- aortic dissection
- recent head injury
- active bleeding
Give 3 relative contraindications to thrombolysis
- pregnancy
- Concurrent anticoagulation
- Major surgery / trauma in the preceding 2 weeks
What pharmacological interventions are used as prevention for ischaemic strokes
- Clopidogrel monotherapy
- if clopidogrel not tolerated/ contraindicated then give aspirin + dipyridamole lifelong
- Atorvastatin after 48h
Hypoglycaemia and hyponatraemia are examples of ‘stroke mimics’, give 2 more examples
- Hepatic encephalopathy
- Brain tumours
- seizures
- vestibular neuritis
- spinal cord lesion
What is a transient ischaemic attack (TIA)
a sudden transient episode of neurologic dysfunction caused by focal brain, spinal cord, or retinal ischaemia, without acute infarction.
What is the most common cause of a TIA
Thrombo-emboli in the internal carotid artery
Give 5 ways a TIA may present
- visual loss: Amaurosis fugax, diplopia, homonymous hemianopia
- aphasia or dysarthria
- ataxia, vertigo, or loss of balance
- unilateral weakness or sensory loss
- typically resolves within 1 hour
What is amaurosis fugax
sudden and temporary loss of vision in one eye due to reduced blood flow to the retina
What investigations should be ordered for a suspected TIA
- MRI brain with diffusion weighted imaging
- Blood glucose - exclude hypoglycaemia
- FBC, PTT, INR
- Serum electrolytes
- ECG
- All TIA patients should have an urgent carotid doppler unless they are not a candidate for carotid endarterectomy