Strokes Flashcards
(63 cards)
Cerebral circulation:
Blood supplied to brain by -
Internal carotid arteries (run anteriorly)
Vertebral arteries (posteriorly)
2x on R and L of each
Cerebral circulation
What structure supplies blood to cerebral cortex?
Circle of Willis!!!! Really important to learn (should be able to draw and label it)
Cerebral circulation
Anterior circle of Willis -
Internal carotid arteries pass up anterior neck and divide to from anterior cerebral artery (ACA) and middle cerebral artery (MCA)
ACA’s join to form anterior communicating artery
Cerebral circulation
Posterior circle of Willis -
Vertebral arteries pass up through foramina in transverse processes of cervical vertebrae and join in front of brain stem to form basilar artery.
Basilar artery divides at upper brain stem into two posterior cerebral arteries (PCA) and is connected to circle of Willis by the Posterior communicating arteries
Why is the circle of Willis anatomically effective?
It protects the brain via collateral circulation
If Damage/blockage in one supply artery, then the other arteries can compensate for this and ensure appropriate profusion for the brain
Arteries that come off circle of Willis eg ACA,MCA and PCA are terminal arteries, therefore areas of brain they supply are not protected by collateral system
Circle of Willis
Anterior cerebral artery -
Supplies medial/superior parts of frontal lobe and anterior parietal lobe
Includes frontal, pre frontal and supplementary motor cortex and parts of primary motor/sensory cortex eg for lower limb
Circle of Willis
Middle cerebral artery -
Supplies greater part of lateral cerebral surface and supplies deep structures including internal capsule and Basal ganglia
Circle of Willis
Posterior cerebral artery -
Occipital lobe, inferno medial surface, temporal lobe and thalamus
Circle of Willis
Basilar artery -
Supplies blood to all of the brain stem (pons,medulla and midbrain) and cerebellum
Circle of Willis
What can MCA damage potentially lead to?
Upper limb motor deficit, facial drop, sensory symptoms and speech deficits
always think about area of brain it supplies
What is a stroke?
Disruption of blood supply to brain resulting in sudden and lasting neurological deficits
Transient ischaemic attack -
(TIA) ‘mini stroke’
Caused by temporary disruption in blood supply to brain
Causes similar symptoms to stroke, but effects last a few minutes to a few hours and will fully resolve within 24 hours
Stoke types
Ischaemic -
Clot/blockage of blood supply
*more common - 85% of strokes
Atheroma - plaque build up of cerebral A
Thrombosis - blood clot in cerebral A
Embolism - blood clot from somewhere else that has moved and is now blocking cerebral A
Most commonly seen MCA>PCA>ACA
Brain stem strokes are less common and more serious
Stroke types
Haemorrhagic -
A bleed (15% of strokes) rupture of blood vessels in brain
Intracranial or intracerebral haemorrhage (ICH) - bleeding on the brain
Subarachnoid haemorrhage (SAH) - bleeding on surface of brain in subarachnoid space*
*discussion as to whether this is a stroke or brain injury. RN, NOT treated within stroke pathway
Aims within first hours of identifying a stroke:
Stroke = medical emergency
Urgent brain imaging - within 1 hour
Thrombolysis within 4 hours for patients with acute ischaemic stroke
Direct admission of patients with acute stroke to hyper acute stroke unit within 4 hours of hospital arrival
Treatments
Ischaemic - thrombolysis -
Clot busting drug, ONLY ischaemic stroke, with aim of restoring blood flow to area and preventing cell death
Needs to be started within 4 hours, but ideally ASAP
Significant inclusion and exclusion criteria
Can significantly increase stroke recovery
Risks of causing bleeding anywhere in the body
Following it, very closely monitored for 24 hours
Available 24hours 7 days a week in UK
Treatments
Ischaemic - thrombectomy -
Newer
Clot removal with catheter inserted through femoral vein and guided via imaging to side of clot in brain
Strict inclusion and exclusion criteria
Can significantly increase post stroke recovery Risks
Risks associated with procedure
Patients usually admitted to critical care post procedure for a night
London available 24hours a day 7 days a week
Midlands available 8-4 Monday-Friday
Treatments
Ischaemic - carotid endarterectomy -
Treatment of carotid artery stenosis by removing plaque build up in carotid artery
Strict inclusion/exclusion criteria
Risks of bleeding and further strokes associated
Treatments
Haemorrhagic -
If on anticoagulants, they need to be urgently reversed
BP must be lowered
For those who develop hydrocephalus (swelling in brain) should be considered for surgical intervention eg. Insertion of external ventricular drain to reduce swelling
For all strokes, secondary prevention of further strokes:
Review risk factors providing treatment and advice to reverse these if possible
Establish cause of current stroke and treating if possible
**national clinical guidelines for stroke - covers all areas of stroke care and guidelines reviewed every 4 years!
Bamford/oxford stroke classification:
Total anterior circulation stroke (TACS)-
Must have all three of the following
- unilateral weakness (and/or sensory deficit) of ace, arm and leg
-homonymous hemianopia
-higher cerebral dysfunction (dysphasia, visuospatial disorder)
Bamford/oxford stroke classification
Partial anterior circulation stroke (PACS) -
Must have two of the following
- unilateral weakness (and/or sensory deficit) or face arm and leg
- homonymous hemianopia
-higher cerebral dysfunction (dysphasia, visuospatial disorder)
Bamford/oxford stroke classification
Lacunar stroke (LACS) -
Must have one of the following
- pure sensory stroke
-pure motor stroke
- sensory-motor stroke
-ataxic hemiparesis
There is no loss of higher cerebral functions
Bamford/oxford stroke classification
Posterior circulation stroke (POCS) -
Must have one of the following
-cranial nerve palsy and a contralateral motor/sensory deficit
-bilateral motor/sensory deficit
-conjugate eye movement disorder (eg. Horizontal gaze palsy)
-cerebellar dysfunction (eg. Vertigo, nystagmus, ataxia)
- isolated homonymous hemianopia