Stroke Flashcards
What is a stroke?
A rapid onset of neurological deficit
Which is the result of a vascular lesion (haemorrhage or thrombus)
Causing infarction of central nervous tissue
What is a transient ischaemic attack?
A transient episode of neurologic dysfunction caused by ischaemia without infarction
The symptoms totally resolve within 24 hours
A mini stroke
What is a completed stroke?
When the neurological deficit has reached its maximum, usually within about 6 hours
Describe the pathophysiology of ischaemic strokes?
Either thrombus or embolism
Thrombus: atherosclerosis in a cerebral artery, this builds up and causes a thrombus which blocks the vessel
Embolus: a clot from another part of the body flows through the bloodstream and gets lodged in a cerebral vessel
Describe the pathophysiology of a haemorrhagic stroke?
An aneurysm ruptures, or something else happens that causes bleeding into the brain tissue damaging it (intracerebral)
Or a berry aneurysm causes a sub-arachnoid haemorrhage?
What are some uncommon causes of stroke?
Venous infarct Carotid / vertebral dissection Fat / air embolism Drugs Migraine Vegetation from endocarditis
Many more
What are the risk factors for a stroke?
Male
Age
Black African
Hypertension Smoking, alcohol Diabetes Heart disease Atrial fibrillation Excess clotting Aneurysm
Why does hypertension increase the risk of a stroke?
Damages arterial walls
Leading to increased risk of thrombus formation
And increased risk of haemorrhage
Why does smoking increase the risk of a stroke?
Increases BP so you have the risk associated with hypertension
Also it has direct effects on the arterial walls
Why does atrial fibrillation increase the risk of a stroke?
High chance of a thrombus forming in the heart, becoming an embolus and going to the brain
The brain is split into 3 regions in terms of blood supply, what are the regions?
And what blood vessels supply the regions?
Anterior: anterior cerebral arteries
Middle: middle cerebral arteries
Posterior: posterior cerebral arteries
Which stroke is worse:
- anterior
- middle
- posterior? Why?
Middle, because many of the important parts of the brain are in the middle
What structures are damaged in an anterior cerebral artery stroke?
Frontal + parietal lobes
- Primary motor cortex
Basal ganglia
Anterior corpus callosum
Clinical features of anterior cerebral artery stroke?
Contra-lateral hemiparesis/plegia
No impetus to move, since primary motor cortex is damaged
Contra-lateral sensory disturbance
Gait apraxia
Incontinence
Drowsiness
Akinetic mutism: decrease in speech
What does a stroke appear like on a CT scan?
Dark lesions
What structures are damaged in a middle cerebral artery stroke?
Lateral frontal, temporal, parietal lobes
Corona radiata
Putamen
Caudate
Globus pallidus
Clinical features of a middle cerebral artery stroke?
Contralateral hemiparesis/plegia
Contralateral sensory loss
Ataxia
Dysphasia / aphasia: Broca’s, Wernicke’s
What happens if Broca’s area is damaged?
Expressive aphasia
Loss of ability to speak coherently
What happens if Wernicke’s area is damaged?
Receptive aphasia
Loss of understanding of speech or written words
What is hemiparesis?
Weakness down one side of the body
What is hemiplegia?
Paralysis of one side of the body
What structures are damaged in a posterior cerebral artery stroke?
Occipital and temporal lobe
Thalamus
Upper brainstem
Midbrain
Clinical features of a posterior cerebral artery stroke?
Contralateral homonymous hemianopsia (loss of half visual field in one eye)
Cortical blindness (blindness caused by damage to occipital lobe)
Visual agnosia: can’t interpret visual info but can see
Dyslexia: problems with discrimination, colour naming
Clinical features of brainstem infarcts?
Depends on exactly where the infarct is
Quadriplegia
Visual problems
Locked-in syndrome
