Stroke COPY Flashcards
What is a stroke?
Rapidly developing clinical signs of focal (or global) disturbance of cerebral function + lasting > 24h
Give the incidence of each type of stroke
Ischaemic 85%
Intracerebral Haemorrhage 10%
SAH 5%
List 3 causes of ischaemic stroke
Thrombus
Embolism
Hypoperfusion
List 3 causes of intracerebral haemorrhage causing stroke
Ruptured cerebral artery
Trauma
Reperfusion injury after ischaemic stroke
List 3 causes of subarachnoid haemorrhage causing stroke
Ruptured Berry aneurysm
Arteriovenous malformation
Trauma
List 5 risk factors for ischaemic stroke
Age >65 HTN Diabetes AF Carotid artery stenosis
List 5 risk factors for intracerebral haemorrhage stroke
Age >65 HTN Vasculitis Malignancy Altered haemostasis e.g. Anticoagulant
List 3 risk factors for subarachnoid haemorrhage stroke
HTN
Smoking
FHx
Describe the epidemiology of stroke
COMMON
Largest cause of disability
3rd most common cause of death in UK
Usual age of stroke patients: 70+
Which vessel is most commonly affected in embolic strokes?
Middle cerebral artery
What are the origins of thrombotic stroke?
Large vessels: Atherosclerosis
Small vessel occlusion (Lacunar)
What causes hypo perfusion and subsequent stroke?
Shock/ bilateral large artery atherosclerosis decreases O2 to whole brain
Results in watershed infarct
Give 5 signs of anterior cerebral artery ischaemic strokes
Hemiparesis (contralateral LOWER LIMB) Hemisensory loss (contralateral LOWER LIMB) Abulia Disinhibition Executive dysfunction
List 5 signs of middle cerebral artery ischaemic strokes
Hemiparesis (contralateral FACE + UPPER LIMB)
Hemisensory loss (contralateral FACE + UPPER LIMB)
Visual field deficits
Apraxia (Parietal lobe)
Speech deficits
List 4 signs of posterior cerebral artery ischaemic strokes?
Contralateral homonymous Hemianopea with macular sparing
Contralateral sensory loss
Memory impairment
Vertigo + nausea
What 8 structures are affected in brainstem stroke?
Medial longitudinal fasciculus; impaired ipsilateral adduction
Motor tract of UMN (corticospinal); ipsilateral face, contralateral body weakness
Medial lemniscus; contralateral loss of proprioception/ vibration
Motor nuclei of CN 3,4,6,12 (ipsilateral)
Spinothalamic tract (contralateral pain + temp): ipsilateral face, contralateral body
Spinocerebellar tract: Ipsilateral ataxia arm + leg
Sympathetic chain: ipsilateral Horner’s
Sensory CN nuclei
List 6 signs seen in intracerebral haemorrhage strokes
Headache Meningism Focal neurological signs N+V Signs of raised ICP Seizures
List 3 signs of SAH strokes
Rapid onset severe headache
Meningeal signs
Sudden onset focal neurological deficits
What bloods should be taken in suspected stroke?
FBC: exclude anaemia + thrombocytopenia
Electrolytes: exclude electrolyte imbalance
Cardiac enzymes: exclude concurrent MI
Glucose
Urea + creatinine: exclude renal failure (choosing tx)
Toxicology screen
Clotting screen: exclude coagulopathy
Why measure serum glucose in suspected stroke?
Hypoglycaemia MIMICS stroke
Hyperglycaemia associated with intracerebral bleeding
Why take a toxicology screen in suspected stroke?
Alcohol/ drugs may mimic
Cocaine + sympathomimetrics associated with ICH
What is the first line investigation in suspected stroke? What can this detect?
Non contrast CT head
Acute hemorrhage: hyperattentuation (blood) + surrounding hypoattenuation (oedema)
Ischemic changes after 6–24h
What further investigations may be performed to identify the cause of a stroke?
ECG: arrhythmias
MRI: if uncertain of dx
How should an ischaemic stroke presenting in less than 4.5 hours be treated medically?
Alteplase (rtPA) IV (after CT excludes haemorrhage)
Aspirin 300mg or Clopidogrel 75mg 24hrs later
What surgical intervention may be considered in ischaemic stroke patients? What is the time frame for this?
Mechanical thrombectomy
< 24 hours since onset
How should an ischaemic stroke presenting later than 4.5 hours be treated?
Aspirin 300mg or Clopidogrel 75mg to prevent further thrombosis
Formal swallow assessment (NG tube may be needed)
GCS monitoring
Thromboprophylaxis
Describe the secondary prevention of stroke
Aspirin 300mg or Clopidogrel 75mg Manage RF: HTN: Antihypertensive AF/ Thrombophilia: anticoagulant e.g. Warfarin High cholesterol: Atorvostatin
What surgical intervention may be performed in an ischaemic stroke no matter the timeframe? In which patients?
Carotid endarterectomy (removal of plaque in carotid artery) In those with carotid stenosis >70% or those with previous stroke stenosis >50%
List 3 sources of emboli that may result in ischaemic stroke
Carotid dissection
Carotid atherosclerosis
Atrial fibrillation
Give 2 prothrombotic states that increase risk of thrombus formation and thus ischaemic strokes
Dehydration
Thrombophilia
Describe the management of haemorrhagic strokes
Mannitol to reduce BP
Reversal of concomitant anticoagulation
Head elevation
Consider craniotomy + surgical clipping of vessel
List 7 complications of stroke
Aspiration pneumonia Cerebral oedema (increased ICP) Immobility: pressure sores, constipation, depression Infections DVT Cardiovascular events Death
What is the prognosis in stroke?
10% mortality in 1st month
Up to 50% that survive will be dependent on others
10% recurrence within 1y
Prognosis for haemorrhagic is WORSE than ischaemic
What speech deficits may manifest in a middle cerebral artery stroke?
Expressive aphasia (Broca's areas) Receptive aphasia (Wernicke's area)
What visual field deficits may arise in middle cerebral artery strokes?
Gaze deviates towards side of infarction
Homonymous hemianopia without macular sparing (contralateral)
Quadrantopia (if superior/ inferior optic radiations affected)
Ischaemic stroke in the right MCA stopping flow to the parietal lobe will cause what additional sign?
Hemineglect (contralateral)
What happens to neurones in ischaemic stroke?
Cell membrane of neurones not getting O2- functionality stops
thus electrical signals not working
Brain cell needs functional membrane for transport- begins to fail.
Water seeps in uncontrollably as membrane loses integrity, cell swells
Swollen cells may undergo apoptosis + necrosis
Whilst swelling with water, density decreases, appears darker (water less dense that brain cells)
How does ischaemic stroke lead to formation of a fluid filled cavity?
Swollen cells go through necrosis + inflammation + permanent damage
Broken down brain cells in brain activates immune system
Macrophages remove necrotic tissue
Results in fluid filled cavity
List 9 common sources of emboli causing ischaemic stroke
Intracranial atherosclerosis (in brain, travels downstream) Small artery disease (in brain- clot break off) Carotid plaque Carotid stenosis Aortic arch plaque AF Cardiogenic emboli Valve disease Ventricular thrombi
What scoring system can assess risk of stroke in patients with AF, and thus guide as to whether anticoagulants would be beneficial?
CHA2DS2VASc CHF HTN Age (2 points if > 75) Diabetes Stroke or clot Hx(2 points) Vascular disease Age (1 point if 65-74) Sex (1 point if F)
Which scoring system estimates risk of major bleeding for patients on anticoagulation for AF?
HAS BLED HTN Abnormal Renal/ Liver Function (1 each) Stroke Hx Bleeding tendency Labile INR (<60% of time in therapeutic range) Elderly (>65) Drugs predisposing to Bleeding or Alcohol Use
What are anticoagulants?
Inhibit clotting factors Red clots: AF + DVT Slow clotting + formation of fibrin Heparin Warfarin Apixaban Rivaroxaban
What are anti platelets?
inhibit platelet aggregation White clots: Stroke + MI Clump when blood is stagnant Aspirin Clopidogrel
