Stroke Flashcards
Definition of a stroke
- A condition characterized by rapidly progressive clinical symptoms and signs of focal and at times global, loss of cerebral function lasting more than 24 hours or leading to death with no apparent cause other than vascular origin
What are the types of stroke
- Ischaemia stroke = 70-80%
- Haemorrhagic stroke = 20-30%
describe some epidemiology of stroke
- Common
- Every 5 minutes someone has a stroke
- Prevalence 5/1000
- Incidence 2/1000
- 8% of deaths
- 1/3 die within a year, most within 4 weeks
- Most than three times as many women die from stroke than breast cancer in the UK
- Leading cause of severe disability
what is the leading cause of severe disability
Stroke
what are the mechanisms by which an intracerebral haemorrhage occurs
- Charcot-Bouchard microaneurysms
- Microbleed
- Haemorrhagic transformation of infarcts
- Vasculitis
What are the primary and secondary causes of intracererbal haemorrhage
Primary
- Hypertension (microaneurysm)
Secondary
- Trauma
- Tumour
- AV malformation
- Venous thrombosis
- Drugs
- Vasculitis
- Coagulopathy
name some complications that can occur with intracerberal haemorrhage
- Local damage
- Local mass effect/herniation – if the haematoma is large enough, can cause subfalcine herniation or tentorial or tonsillar herniation
- Raised ICP – causes brain perfusion to fall (CPP) and leads to ischemia and hypoxia
- Hydrocephalus – if there is an outflow obstruction caused by the stroke, this causes the ventricles to expand and the brain matter to be squashed
describe the management that is used in stroke
- Establish cause – imaging/angiography, clotting/platelet function
- Stop aspirin or warfarin
- Treat complications ICP management, Surgery/EVD
- Treat risk factors – blood pressure
- Rehabilitation
- Role of pro-coagulants
- Role of surgery
- Role of aggressive BP lowering – overall advantage in gentle blood pressure lowering
what are the two types of ishcemic stroke
thrombotic
embolic
what type of ishcemica vessel stroke can occur
- Large vessel stroke
* Small vessel stroke (lacunar).
Describe how exncitoxcity can cause stroke
- Glutamate excitocity
- Ischemia leads to the failure of sodium and potassium pumps
- This leads to depolarisation and the release of glutamate
- Affects AMPA receptors causing slow excitoxity and NDMA receptors causing fast ecotoxicity
- This causes influence of calcium via the NMDA receptors
- Leads to elevated intracellular calcium which can cause the release of free radicals and cell death
what is cerebral blood flow determined by
Cerebral perfusion pressure
what are the 3 regions of the brain that focus around a stroke and what happens to the cells there
- The centre – cells here face inventible death
- The penumbra region – neurones are hypoxic and/or damaged but survival is possible
- At a distance there are cells supplied by other arterial arteries or there is enough oxygen that pass through which keeps them alive
What are the causes of ischaemic stroke
- 25% small vessel stroke – arterioathersclerosis
- 15% cardiac embolic due to AF – left atrial appendage, can cause an embolism, travels to the brain, occludes small blood vessels
- 5% carotid dissection
- Atherosclerosis 50%= carotid stenosis 10% - important- surgery or alternative stenting
- Vasculitis less than 1%
- Haematological less than 1%
What is the major cause of ischemic stroke
- atherosclerosis
What are the risk factors for stroke
- Demographic: age, male, race, socioeconomic status
- Lifestyle: smoking, weight, inactivity, alcohol.
• Medical: o Hypertension o Hypercholesterolaemia o Diabetes o Vascular disease o Cardiac o Rare Associations.
for every 1mm/L decrease in LDL there is a ….
15% decrease in risk of stroke
What is the pyramidal system made up of
Primary motor cortex internal capsule cerebral peduncles decussation of pyramids descending CS.
What happens if you have an ischemic stroke at any point along the pyramidal system
• Ischemic stroke deficits at any point of this route motor deficits (e.g. MCA stroke).
how do you classify strokes
- By vascular anatomy = MRI, and CT
- By clinical picture = the oxford bamford classification
- By aetiology – The TOAST classification
what arteries in stroke cause visual defects
PCA stroke
MCA stroke
describe the Oxford Bamford classification for
- anterior circulation
- posterior cinrcualtion
- lacunar circulation
Anterior circulation – TACI/PACI (15/35%)
- Unilateral motor deficit
- Homonymous hemianopia
- Higher cerebral function (dysphasia, neglect)
Posterior circulation – POCI (25%)
- Pure hemianopia
- Cerebellar sgins
- Diplopia and CN palsy
- Bilateral/crossed sensory motor signs
Lacunar – LACI (25%)
- Pure motor (50%)
- Pure sensory (5%)
- Ataxic hemiparesis (10%)
- Sensorimotor stroke(35%)
what happens if you have stroke in the anterior circulation
- Unilateral motor deficit
- Homonymous hemianopia
- Higher cerebral function (dysphasia, neglect)
what happens if you have a stroke in the posterior circulation
- Pure hemianopia
- Cerebellar sgins
- Diplopia and CN palsy
- Bilateral/crossed sensory motor signs
What happens if you have a stroke in the lacunar circulation
- Pure motor (50%)
- Pure sensory (5%)
- Ataxic hemiparesis (10%)
- Sensorimotor stroke(35%)
name investigations that are carried out for stroke
- CT/MRI
- blood
- carotid doppler
- ECG
- Echo
- HIV test
- drug screen
- Cather angiography
- if there less than 50 years old consider vasculitis screen
what in a blood test do you look for stroke
o FBC o ESR o Fasting glucose o Cholesterol o VDRL
what treatment can be used for stroke
- Consider thrombolysis
- Transfer to a stroke unit
- Receive antiplatlet therapy
- Address risk factors
- Treat complications
- MDT rehabilitation
- Advice and education
How many patients are suitable for thormbolysis
20% of patients are suitable for thrombolysis.
- usually works best within 3 hours of stroke, not effective after7 hours
What patients are suitable for a thrombecotmy
5% of patients are suitable for thrombectomy.
What is a thrombectomy
this is the removal of a clot from the Brain
what are the current guidelines for drug treatment of stroke
• Aspirin 300mg for 2/52 then Clopidogrel 75mg monotherapy
OR
• Aspirin 75mg + Dipyridamole MR 200mg BD
What is a TIA
- An acute loss of focal cerebral or monocular function with symptoms lasting less than 24 hours and which after adequate investigation is presumed to be due to embolic or thrombotic vascular disease
what is the ABCD2 score
- Age
- Blood pressure
- Clinical features
- Duration
- Diabetes
What can cause a TIA
- Usually ischaemia/embolic
- Sometimes microbleeds
- Rarely haemodynamic
describe what happens in TIA management
- CT
- Doppler/CTA
- ECG
- Start Antiplatelets
Admit if Atrial Fibrillation(unless FRT) Carotid stenosis(for surgery) >2 in 1 week(forIx) ABCD2 >4 and no clinic in 24hrs
IfABCD2 <4 &none of above
Can refer to local TIA clinic
