Lecture 16 — Stroke Flashcards
What is the Definiton of a stroke?
A serious life threatening condition that occurs when the blood supply to part of the brain is cut off with signs and symptoms persisting for longer than 24hrs
What is a transient ischaemic attack (TIA)?
The same clinical features of a stroke but resolves within 24hrs (essentially a stroke resolving in 24hrs)
What are the main types of stroke?
Ischaemic stroke (thromboembolism)
Haemorrhagic (rupture of blood vessels)
Arterial dissection
Venous sinus. Thrombosis
Hypoxic brain injury
What occurs in an ischaemic stroke?
Occlusion of a blood vessel usually due to the rupture of an atherosclerotic plaque
What are the main types of Haemorrhagic stroke?
Subarachnoid haemorrhage
Intracerebral haemorrhage (blood vessel in the brain)
How does venous sinus thrombosis lead to a stroke occurring?
Impairs the venous drainage (back pressure) which impairs arterial blood flow to the brain leading to ischaemia
What is the emergency management of stroke?
Do CT head to determine if its a bleed
Give thrombolysis if less than 4hrs since stroke and stroke cause is not a bleed
How does blood appear on a CT head?
White
How does blood appear on an MRI?
High signal area
Slide 6:
What type of haemorrhage is seen on the right CT?
Describe it:
Subarachnoid haemorrhage
Blood has filled the basal cisterns producing. A 5 pointed star pattern
How does an acute ischaemic stroke appear on CT?
Likely no changes however you may see a hyper dense area indicating a thrombus
Slide 7:
What is visible on the left CT?
Hyper dense Middle cerebral artery indicating a thrombus in this area
What type of imaging is very good at identifying ischaemic stroke?
How does it appear?
MIR
High signal area (whiter area)
How may a head CT change as a stroke evolves?
Can look normal but then weeks area have darker areas indicating neuronal damage and oedema
What makes up the anterior brain circulation?
Anterior and middle cerebral arteries
What arteries feed the anterior circulation of the brain?
Internal carotid arteries
What arteries supply the posterior circulation of the brain?
Vertebral arteries
Go to slide 9 and complete the blood supply to the brain:
What part of the brain does the Anterior Cerebral Artery supply? (ACA)
Medial aspect of frontal and parietal lobes (motor and sensory homunculus)
Corpus callosum
What part of the brain do the Middle Cerebral Arteries supply?
Lateral aspect of frontal and parietal lobes (motor and sensory homunculus)
Lateral aspect of Superior temporal lobe
Deep structures like internal capsule, lentiform nucleus and caudate
What branch from the middle cerebral artery supply the internal capsule?
Lenticulostriate arteries
What part of the brain do the posterior cerebral arteries supply?
Occipital lobe
Inferior temporal lobe
Thalamus
What is the most commonly affected artery in stroke?
Middle cerebral artery
How does an Anterior Cerebral artery infarction present in a patient?
Think about the areas which the anterior cerebral artery supplies
Contralateral lower limb weakness
Contralateral lower limb sensory change
Urinary incontinence
Apraxia
Dysarthria/aphasia (rare)
Split brain syndrome (rare)
Why does an Anterior Cerebral artery infarct cause Contralateral lower limb weakness and sensory change?
ACA supplies medial aspect of frontal and parietal lobes which include the medial aspect of primary sensory and motor cortex which supplies the lower limb
Why does an anterior cerebral artery infarct cause urinary incontinence?
The paracentral lobules which are responsible for supplying the external urinary sphincter are represented medially in the brain
Why can an Anterior Cerebral artery infarct cause Split brain syndrome or alien hand syndrome?
Branch of the ACA supplies the corpus callosum which is a white matter tract allowing communication between the 2 hemispheres
What is Apraxia?
Difficulty doing every day tasks (motor planing)
Why can an Anterior Cerebral artery infarction cause apraxia?
Damage to the left frontal lobe due to the ACA supplying this part of the medial frontal lobe