Stroke (ischaemic and haemorrhagic) Flashcards
Definition
· 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:
o Location - anterior circulation vs posterior circulation
o Pathological Process - infarction vs haemorrhage
Aetiology/Risk factors (infarction (80%))
o 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)
o 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
o 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
o Others
· Vasculitis
· Cocaine (arterial spasm)
Aetiology/Risk factors (haemorrhage (10%))
o Hypertension
o Charcot-Bouchard microaneurysm rupture (DEFINITION: aneurysms within the brain vasculature that occur in small blood vessels)
o Amyloid angiopathy
o Arteriovenous malformations
o 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+
Presenting 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 on physical examination
· Examine for underlying cause (e.g. atrial fibrillation)
· Infarction - see next 3 flashcards
Signs on physical examination (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
Signs on physical examination (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)
Signs on physical examination (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
o Clotting profile - check if thrombophilia (especially in young patients)
· ECG
o Check for arrhythmias that may be the source of the clot
· Echocardiogram
o Identify cardiac thrombus, endocarditis and other cardiac sources of embolism
· Carotid Doppler Ultrasound
o Check for carotid artery disease (e.g. atherosclerosis)
· CT Head Scan
o Rapid detection of haemorrhages
· MRI-Brain
o Higher sensitivity for infarction but less available
· CT Cerebral Angiogram
o Detect dissections or intracranial stenosis
Management plan (hyperacute stroke)
o If < 4.5 hrs from onset
o Exclude haemorrhage using CT-head
o If haemorrhage excluded, thrombolysis may be considered
Management plan (acute ischaemic stroke)
o Aspirin + Clopidogrel to prevent further thrombosis (once haemorrhage excluded on CT head)
o Heparin anticoagulation considered if there is a high risk of emboli recurrence or stroke progression
o Formal swallow assessment (NG tube may be needed)
o GCS monitoring
o Thromboprophylaxis
Management plan (secondary prevention)
o Aspirin and dipyridamole
o Warfarin anticoagulation (atrial fibrillation)
o Control risk factors: hypertension, hyperlipidaemia, treat carotid artery disease
· Surgical Treatment - carotid endarterectomy
Possible 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