Stroke Flashcards
Define
rapid permanent neurological deficit from cerebrovascular insult. Also defined clinically, as focal or global impairment of CNS function developing rapidly and lasting > 24 hrs
Can be subdivided based on:
Location - anterior circulation vs posterior circulation
Pathological Process - infarction vs haemorrhage
Causes
INFARCTION (80%)
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
Others
- Vasculitis
- Cocaine (arterial spasm)
HAEMORRHAGE (10%)
- 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
Epidemiology
COMMON
Incidence: 2/1000
3rd most common cause of death in industrialised countries
Usual age of stroke patients: 70+
Symptoms
- 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
Signs
Examine for underlying cause (e.g. atrial fibrillation)
Infarction
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
Anterior Circulation
Anterior Cerebral
- Lower limb weakness
- Confusion
Middle Cerebral
- Facial weakness
- Hemiparesis (motor cortex)
- Hemisensory loss (sensory cortex)
- Apraxia
- 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)
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
Investigations
Bloods
- Clotting profile - check if thrombophilia (especially in young patients)
ECG
- Check for arrhythmias that may be the source of the clot
Echocardiogram
- Identify cardiac thrombus, endocarditis and other cardiac sources of embolism
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
Management
HYPERACUTE STROKE
- If < 4.5 hrs from onset
- Exclude haemorrhage using CT-head
- If haemorrhage excluded, thrombolysis may be considered
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
Secondary Prevention
- Aspirin and dipyridamole
- Warfarin anticoagulation (atrial fibrillation)
- Control risk factors: hypertension, hyperlipidaemia, treat carotid artery disease
Surgical Treatment - carotid endarterectomy
Complications
Cerebral oedema (increased ICP)
Immobility
Infections
DVT
Cardiovascular events
Death
Prognosis
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
