PBL 5 Flashcards
What is the difference between a stroke and a TIA
Stroke is cerebral deficit lasting > 24 hours, whereas TIA is a sudden focal deficit lasting less than 24 hours with complete recovery
What are the main symptoms of stroke?
Sudden limb weakness on one side of the body
Loss of sensation/abnormal sensations on one side of the body
Difficulty speaking (aphasia)
Slurred speech (dysarthria)
Dizziness, blurring, loss of vision in one eye
Loss of balance and coordination
Inability to swallow safely
What does the acronym F.A.S.T stand for?
Face - look for facial asymmetry
Arms - looks for sudden arm weakeness
Speech - look for speech problems
Time - time to call 999
Which areas of the cerebrum are supplied by the aneterior cerebral artery?
What effect would occlusion result in?
Medial portions of the frontal lobes, and superior medial parietal lobes
Occlusion - paralysis and sensory loss in the contralateral lower part of the body
Which areas of the cerebrum are supplied by the middle cerebral artery?
What effect would occlusion result in?
Lateral surface of the hemisphere (apart from inferior temporal lobe). Includes Broca’s and wernicke’s
Occlusion results in paralysis/sensory loss to contralateral upper limb and face.
Occlusion in dominant hemisphere results in aphasia.
Occlusion in non dominant hemisphere results in neglect - not being able to recognise your own limbs as your own
Which areas of the cerebrum are supplied by the basilar artery?
What effect would occlusion result in?
Brainstem
Occlusion Results in paralysis of all 4 limbs, eye movement abnormalities
Coma is caused by damage to reticular activating system
Locked in Syndrome
Respiratory failure
Which areas of the cerebrum are supplied by the posterior cerebral artery?
What effect would occlusion result in?
Visual cortex, thalamus, hippocampus, posterior limb internal capsule
Occlusion Results:
memory deficit - due to hippocampus formation
Contralateral loss of pain and temperature
Visual field defects
What is a watershed infarct?
This is when the blood supply to two adjacent cerebral arteries is compromised
Why is stroke more likely to occur in people with atrial fibrilation?
Atria is never able to empty properly, so blood left in the atria is able to form clots.
Clots are then pushed through the aorta to the head and stroke occurs
What is a lacunar infarction?
These are small infarcts that occur when one of the small arteries deep in the brain becomes blocked when part of its wall deteriorates
How do cells in the penumbra become damaged in stroke?
Cells dying in the core region release toxins into the surrounding area and these have the potential to kill the cells in the penumbra
What are the main damage mechanisms that occurs following ischemia?
Excitotoxicity Reperfusion injury Oxidative stress Apoptosis Inflammation
How does ischemia cause excitotoxicity in stroke?
What other damage mechanisms can excitotoxicity lead to?
Hypoxia leads to inadequate ATP, leading to failure of membrane pumps
This causes a release of glutamate at synaptic terminals
Glutamate binds to NMDA receptors and causes rapid calcium ion influx. This triggers the formation of free radicals which can in turn causes necrosis and infalmmation
How does central inflammation occur in stroke?
Increased immune cells in the brain activate the BBB
Chemokines lead out of brain and activate the liver
The liver produces chemokines and cytokines which active bone marrow
Bone marrow produces white blood cells e.g, neutrophils
These then infiltrate the BBB and inflammation occurs in the brain
What is a thrombectomy?
What is the timescale for the procedure following stroke?
Where you physically remove the blood clot using a mesh device
Must be done within 8 hours of symptoms
What is the name of the surgery carried out in a internal carotid artery following stroke?
Endarterectomy
