Pathophysiology of Stroke Flashcards
What are the 4 main features of a stroke?
- Rapid onset of symptoms
- Signs of focal disturbance of cerebral function
- Symptoms last 24 hours or longer
- No apparent cause other than vascular
What is a stroke in evolution?
A stroke that is actively progressing, with symptoms worsening
Which type of stroke is more likely to effect a specific region, leading to stereotyped deficits?
Ischaemic
Why do haemorrhagic strokes produce less predictable symptoms?
Because of possible secondary mechanisms such as raised intracranial pressure, cerebral oedema, or compression
What might more diffuse, global cerebral dysfunction indicate?
Cerebrovascular disorder (not “stroke”)
Which brain areas are supplied by the anterior (carotid) circulation?
Most of the cerebral cortex, subcortical white matter, basal ganglia, internal capsule
Lesions in the anterior circulation are more likely to lead to what kind of dysfunction?
Hemispheric, such as aphasia, apraxia, agnosia
Which brain areas are supplied by the posterior (vertebrobasilar) circulation?
The brainstem, cerebellum, thalamus, and parts of the occipital and temporal lives
Lesions in which part of the circulation are more likely to cause signs of brainstem dysfunction?
The posterior (vertebrobasilar) circulation
Name some of the main signs of posterior lesions and brainstem dysfunction?
Coma, drop attacks, nausea, ataxia, sensorimotor deficits
What is a TIA?
Transient ischaemia attack - when the deficits resolve quickly, typically within an hour
What type of emboli causes TIAs with different presentations?
Cardiac emboli
What type of stroke causes recurrent TIAs with identical presentations?
Thrombosis / cerebral embolism
What is a minor stroke?
An event with deficits that last longer than TIAs but resolve completely within a few days
What is the most common cause of stroke?
Ischaemia (90% of strokes)
What are the two main arteries supplying blood to the brain?
The common carotid artery and the vertebral artery
What is the ring of vessels that connects the anterior and posterior circulations of the brain?
The circle of Willis
What are the 4 main arteries of the internal carotid circulation?
- Anterior choroidal
- Anterior cerebral
- Middle cerebral
- Lenticulostriate
What are the 6 main arteries of the vertebrobasilar circulation?
- Vertebral/basilar
- Posterior inferior cerebellar
- Anterior inferior cerebellar
- Superior cerebellar
- Posterior cerebral
- Thalamic
Which artery connects the anterior circulation of the right and left hemispheres?
The anterior communicating artery
What is the role of the posterior communicating arteries?
To provide an alternative pathway if there is a blockage in the internal carotid or vertebral arteries
What is ischaemia?
The interruption of blood flow to the brain, depriving cells of glucose and oxygen
What is an infarction?
Tissue death due to inadequate blood supply, typically within the ischaemic core when flow is less than 20% of its normal amount
What is selective vulnerability?
In mild ischaemia, when neuronal populations are lost preferentially
