Stroke (Ischaemic + Haemorrhagic) Flashcards
What is the definition of stroke?
A rapid permanent neurological deficit from cerebrovascular insult.
Also defined clinically, as focal or global impairment of CNS function developing rapidly and lasting more than 24 hrs
How can strokes be subdivided?
Can be subdivided based on:
- Location - anterior circulation vs posterior circulation
- Pathological Process - infarction vs haemorrhage
What is the aetiology and risk factors involved in ischaemic stroke?
Causes 80% of strokes and they can be caused by the following:
- Thrombosis:
Can occur in small vessels (lacunar infarcts)
Can occur in larger vessels (e.g. middle cerebral artery)
Can arise in prothrombotic states (e.g. dehydration, thrombophilia) - Emboli:
From carotid dissection, carotid atherosclerosis, atrial fibrillation
NOTE: they can arise from venous blood clots that pass through a septal defect (e.g. VSD) and get lodged in the cerebral circulation - Hypotension:
If the blood pressure is below the autoregulatory range required to maintain cerebral blood flow, you can get infarction in the watershed zones between different cerebral artery territories - Other causes
Vasculitis
Cocaine (arterial spasm)
What is the aetiology of haemorrhagic strokes
- Causes 10% of strokes and they are caused by the following:
Hypertension
Charcot-Bouchard microaneurysm rupture (DEFINITION: aneurysms within the brain vasculature that occur in small blood vessels)
Amyloid angiopathy
Arteriovenous malformations
Less common: trauma, tumours, vasculitis
What is the epidemiology of stroke?
COMMON
Incidence: 2/1000
3rd most common cause of death in industrialised countries
Usual age of stroke patients: 70+
What are the presenting symptoms of stroke?
- 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
What are the signs of an ischaemic stroke caused by lacunar infarcts?
Affecting the internal capsule or pons: pure sensory or motor deficit (or both)
Affecting the thalamus: loss of consciousness, hemisensory deficit
Affecting the basal ganglia: hemichorea, hemiballismus, parkinsonism
What are the signs of an ischaemic stroke affecting anterior circulation?
Depends on which artery is affected:
Anterior Cerebral
- Lower limb weakness
- Confusion
Middle Cerebral
- Facial weakness
- Hemiparesis (motor cortex)
- Hemisensory loss (sensory cortex)
- Apraxia (Difficulting planning motor actions)
- Hemineglect (parietal lobe)
- Receptive or expressive dysphasia (due to involvement of Wernicke’s and Broca’s areas)
- Quadrantopia (if superior or inferior optic radiations are affected)
What are the signs of an ischaemic stroke affecting posterior circulation?
Posterior Cerebral - hemianopia
Anterior Inferior Cerebellar - vertigo, ipsilateral ataxia, ipsilateral deafness, ipsilateral facial weakness
Posterior Inferior Cerebellar (affected in lateral medullary syndrome) - vertigo, ipsilateral ataxia, ipsilateral Horner’s syndrome, ipsilateral hemisensory loss, dysarthria, contralateral spinothalamic sensory loss
Basilar Artery - cranial nerve pathology and impaired consciousness
Multiple Lacunar Infarcts - vascular dementia, urinary incontinence, gait apraxia, shuffling gait, normal or excessive arm-swing
Intracerebral - headache, meningism, focal neurological signs, nausea/vomiting, signs of raised ICP, seizures
What are the appropriate investigations when suspecting stroke?
- Bloods - Check clotting profile for thrombophilia (especially in young patients)
- ECG - Check for arrhythmias that may be souce of the clot
- Echocardiogram - Identify cardiac thrombus, endocarditis and other sources of cardiac embolus
- Carotid Doppler Ultrasound - Check for carotid artery disease (e.g. atherosclerosis)
- CT Head Scan - Rapid detection of haemorrhages
- MRI-Brain - Higher sensitivity for infarction but less available
- CT Cerebral Angiogram - Detect dissections or intracranial stenosis
Describe the management of a hyperacute stroke
If less than 4.5 hrs from onset
Exclude haemorrhage using CT-head
If haemorrhage excluded, thrombolysis may be considered
Describe the management of an acute ischaemic stroke
Aspirin + Clopidogrel to prevent further thrombosis (once haemorrhage excluded on CT head)
Heparin anticoagulation considered if there is a high risk of emboli recurrence or stroke progression
Formal swallow assessment (NG tube may be needed)
GCS monitoring
Thromboprophylaxis
Describe the secondary prevention involved in the management of stroke
Aspirin and dipyridamole
Warfarin anticoagulation (atrial fibrillation)
Control risk factors: hypertension, hyperlipidaemia, treat carotid artery disease
What surgical treatment may be used in stroke?
Carotid endarterectomy - Used to correct severe carotid stenosis
What are the potential complications of a stroke?
Cerebral oedema (increased ICP)
Immobility
Infections
DVT
Cardiovascular events
Death
