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
