Stroke Flashcards
Most common cause of long term disability in UK
20% of hospital beds
£5bn per year
Stroke
Definition of a stroke
Neurological deficit of sudden onset lasting over 24hrs if vascular origin
Symptoms of stroke
Loss of Power Sensation Speech Vision Coordination
Dysarthria Vs dysphasia
verbal problems
Dysarthria is muscles
Dysphasia is processing in brain
2 causes of stroke
Blockage of blood vessel to brain (ischaemic stroke) - dark 85%
Haemhorragic stroke from ruptured blood vessel in brain - white 15%
2 arteries to brain
Internal carotid and vertebral
2 arteries to brain
External carotid and vertebral
What blood vessels supply anterior brain
Internal carotid, into middle cerebral and anterior cerebral
What blood vessels supply posterior brain
Vertebral artery into cerebellar, basilar and posterior cerebral
The homunculus
Supplies foot and leg centrally then hip trunk arm and and face
A small stroke in the pons or internal capsule of these nerves will result in major deficit
Causes of ischemic stroke
Large artery atherosclerosis 35%
Cardioembolic eg AF 25%
Small artery occlusion eg lacunar stroke 25%
Undetermined 10-15%
Rare eg arterial dissection of venous sinus thrombosis <5%
Causes of haemorrhagic stroke
Primary intracerebral hemorrhage 70%
Secondary eg subarachnoid or artiovenous 30%
Where does carotid stenosis usually happen
Internal and external bifurcation
Where does carotid stenosis usually happen
Internal and external bifurcation
Cardioembolic stroke
AF causes clot formation in atrium then this goes to brain
Lacunar stroke
Affects a small part of brain in medial and lateral lenticulostriate arteries off of middle cerebral artery
May be unnoticed
Carotid dissection
Can happen with lots of exercise
What can you tell from symptoms and signs
What side of brain Brainstem or not If cortex is involved If lesion is in deep white matter (lacunar) What blood vessel
Why bother with localisation of embolus/haemorrhage
Confirm stroke
Better image selection
Indication of cause
Prognosis
Unilateral (one eye) field loss
One optic nerve compression
Bitemporal hemianopia (tunnel vision)
Chiasmal (cross over of optic nerves) by pituitary tumor
Homonymous hemianopia (can’t see one side from both eyes)
Left cerebrovascular event
Stroke subtypes
TACS
PACS
LACS
POCS
TACS
20% of strokes
Weakness and sensory deficit
Homonymous hemianopia
Higher cerebral dysfunction (can’t talk or is clumsy)
Usually due to occlusion if proximal middle cerebral artery or internal carotid artery
60% m@1y and 6% r@1y
PACS
35% of strokes
2 or 3 of TACS criteria or restricted motor/sensory deficit eg one limb face and hand or just higher cerebral dysfunction
More restricted cortical infarcts eg occlusion if branches of middle cerebral artery
16% m@1y and 17% r@1y
LAC
Most common is pure weakness in one side in whole of 2 of face/arm/leg
Pure sensory in same distribution
Sensorimotor is combination
11% m@1y and 9% r@1y
POCS
25%
Affects brainstem, cerebellar or occipital lobes
Variable, complex presentation eg
Bilateral motor/sensory deficit Disordered conjugate eye movements Homonymous hemianopia Disordered breathing Tinnitus vertigo
19% 1 year mortality and 20% recurrence
Why do patients do better in stroke wards
Mobile asap Concentration on simple things Swallowing problems common in half Earth therapy Concentration of expertise
How many neurons are lost each minute a large vessel occlusion isn’t treated
1.9 million
Time after which TPA (tissue plasminogen activator) isnt beneficial
330mins (4.5 hours)
Clot busting drug found beneficial up to 4.5 hours by MHRA
Alteplase
% of patients alive and independent T 90days
With just IVT >40%
With IVT and early thrombectomy 62%
Assessment of stroke patients in A&E
If no neuro problems and AF or resolved AC problems, discuss with stroke bleep holders
Neuro problems>4.5hrs contact stroke team
<4.5hrs urgent CT then stroke bleep
Contraindications to thrombolysis
Age (<80years usually)
Recent bleeding, high BP etc
SIGN guidelines
Mortality with MCA (middle cerebral artery) stroke is up to 80%
In under 60s hemicraniectomy reduced mortality from 80% to 27%
SIGN guidelines
Mortality with MCA (middle cerebral artery) stroke is up to 80%
In under 60s hemicraniectomy reduced mortality from 80% to 27%
When to do hemicraniectomy
Up to 60y with MCA ischemic stroke with massive cerebral oedema, within 48 hours of onset
What % of patients does aspirin in 0-48 hours benefit
65% of ischemic stroke, 12 prevented deaths per 100 treated
Benefits of giving stroke unit
90% of patients benefit, 5 deaths per 100 prevented
Benefits of thrombolysis
10% of strokes, 1 death prevented per 100
Benefits of hemicraniectomy
0.5% of strokes, 22 deaths prevented per 100
Risk for early recurrent stroke in the first 2 weeks
14% in Tia and stroke
1/3 of Tia patients will have an acute stroke at some point
treatment of tia and secondary prevention drugs used
Decreases risk of recurrent stroke
Clopidogrel 75mg or aspirin 75mg with MR 200mg
Statins
Blood pressure drugs
When to do carotid endarterectomy
Anterior circulation occluded
Tia or stroke with good recovery
70% occlusion
