Stroke Flashcards
What is a stroke?
An acute neurological condition resulting from a disruption in cerebral perfusion, lasting more than 24 hours
How can a stroke be categorised?
- Location - anterior circulation vs posterior circulation
- Pathological Process - infarction vs haemorrhage
What is the difference between an ischaemic and haemorrhagic stroke?
- Ischaemic Stroke (85%) → cerebral infarction due to insufficient blood flow due to a thrombus or embolus
- Haemorrhagic Stroke (15%) → cerebral infarction due to haemorrhage (rupture of blood vessel causing leakage of blood into the brain)
What are the different causes of stroke?
- Infarction:
- thrombosis
- emboli
- hypotension
- others (vasculitis, cocaine: arterial spasm) - Haemorrhage:
- Hypertension
- Charcot-Bouchard microaneurysm rupture (DEFINITION: aneurysms within the brain vasculature that occur in small blood vessels)
- Amyloid angiopathy
- Arteriovenous malformations
- Anticoagulant therapy
- Less common: trauma, tumours, vasculitis
What are risk factors for stroke?
Age >65, hypertension, diabetes, AF, obesity, smoking, high cholesterol
What are the different posterior stroke syndromes?
- Basilar artery occlusion is more likely to present with locked in syndrome (quadriparesis with preserved consciousness and ocular movements), loss of consciousness, or sudden death.
- Anterior inferior cerebellar artery results in lateral pontine syndrome, a condition similar to the lateral medullary syndrome but with additional involvement of pontine cranial nerve nuclei.
- Wallenberg’s syndrome (lateral medullary syndrome) ipsilateral Horner’s syndrome, ipsilateral loss of pain and temperature sensation on the face, and contralateral loss of pain and temperature sensation over the contralateral body.
- Weber’s syndrome/medial midbrain syndrome (paramedian branches of the upper basilar and proximal posterior cerebral arteries): ipsilateral oculomotor nerve palsy and contralateral hemiparesis.
Summarise the epidemiology of stroke
COMMON
Incidence: 2/1000
3rd most common cause of death in industrialised countries
Usual age of stroke patients: 70+
Recognise the presenting symptoms of stroke
(Stroke affects 5 key functions: motor, sensation, speech, balance, vision)
- SUDDEN-ONSET
- Weakness
- Sensory, visual or cognitive impairment
- Impaired coordination
- Impaired consciousness
- Head or neck pain (if carotid or vertebral artery dissection)
- Enquire about time of onset (critical for emergency management if < 4.5 hrs)
- Enquire about history of AF, MI, valvular heart disease, carotid artery stenosis, recent neck trauma or pain
How does a patient with a stroke in the middle cerebral artery present?
MCA (Most Common) → contralateral weakness and sensory loss more marked in the upper limbs and lower half of the face, contralateral homonymous hemianopia, aphasia (broca = expressive, wernicke = receptive)
Broca’s (Left Frontal Lobe) ⇒ responsible for speech production (expressive aphasia)
Wernicke’s (Left Temporal Lobe) ⇒ responsible for speech comprehension (receptive aphasia)
Broca’s = broken speech. Wernicke’s = wer di ficke are you talking about (makes no sense).
How does a patient with a stroke in the anterior cerebral artery present?
ACA → contralateral weakness and sensory loss more marked in the lower limbs, abulia (behavioural changes), urinary incontinence
How does a patient with a stroke in the posterior cerebral artery present?
PCA → contralateral homonymous hemianopia with macular sparing, contralateral sensory loss, memory deficits, vertigo, nausea, visual agnosia (difficulty recognising familiar objects/faces)
How does a patient with posterior circulation stroke present?
Posterior Circulation Stroke → damage to the brainstem. Gives ipsilateral symptoms.
DANISH (Cerebellar Signs) ⇒ dysdiadochokinesia (the inability to perform rapid alternating muscle movements), ataxia (group of disorders that affect co-ordination, balance and speech), nystagmus, intention tremor, slurred speech, hypotonia
What investigations are used to diagnose/ monitor stroke?
- Pulse and BP – check for AF or hypertension (do not treat HT as can impact cerebral perfusion)
- Bloods
- Clotting profile - check if thrombophilia (especially in young patients)
- Check blood glucose and aim for 4-11 - ECG/24 hour holter
Check for arrhythmias that may be the source of the clot - Non-Contrast CT Head → exclude haemorrhage (confirm ischaemic stroke)
- (Normal CT does not rule out an ischaemic stroke)
- PCA Infarct - CT Angiogram → look for which vessel is occluded
- Look for cause of stroke (after patient has been treated) → Echocardiogram (structural heart disease), Ambulatory ECG (atrial fibrillation), Carotid Doppler (carotid atherosclerosis, if >70% occlusion, carotid endarterectomy recommended)
- ROSIER Score - differentiates between a stroke and stroke mimics
Generate a management plan for stroke
- 1st Step → CT Head before thrombolysis to rule out haemorrhage (esp. if on warfarin/DOAC/has bleeding disorder)
- <4.5 hrs from onset = thrombolysis (IV alteplase)
- Thrombectomy + Thrombolysis for anterior circulation strokes (ACA or MCA demonstrated by CTA) within 6 hrs
- Contraindications to Thrombolysis
OR - > 4.5 hrs = conservative management (Aspirin, 300mg oral)
- After 2 weeks = stop aspirin 300mg daily + start clopidogrel daily (75mg, lifelong)
- Aspirin + modified release dipyridamole if clopidogrel not tolerated (may cause diarrhoea and abdo discomfort)
- Patients with stroke due to AF → anticoagulation (DOAC) is initiated 2wks after stroke - Surgery (if ipsilateral carotid artery stenosis >50%) ⇒ carotid endarterectomy
- A decompressive hemicraniectomy should be considered in patients who are less than 60 years old, have severe stroke symptoms, reduced consciousness, and CT-defined infarct of at least 50% of the middle cerebral artery territory - Haemorrhagic Stroke → stop anticoagulants (if warfarin consider vitamin K and prothrombin concentrate)
- also blood pressure control is vital for HS (give labetalol)
Identify the possible complications of stroke
Aspiration pneumonia
Cerebral oedema (increased ICP)
Immobility – pressure sores, constipation, depression
Infections
DVT
Cardiovascular events
Death
Summarise the prognosis for patients with stroke
10% mortality in the first month
Up to 50% that survive will be dependent on others
10% recurrence within 1 year
Prognosis for haemorrhagic is WORSE than ischaemic
What scoring system is used to assess the functional status of patients post stroke?
Barthel index
which arteries are involved in an anterior circulation stroke?
both the middle and anterior cerebral arteries
which arteries are involved in a posterior circulation stroke
2 vertebral arteries, basilar artery, 2 posterior cerebral arteries, and their branches
