[2] Stroke Classification Flashcards
What are the two major types of stroke?
- Ischaemic
- Haemorrhagic
What % of strokes are ischaemic?
87%
What % of strokes are haemorrhagic?
13%
What is an ischaemic stroke?
Reduced blood supply to an area of the brain resulting in tissue hypoperfusion
What can be the underlying mechanisms leading to ischaemic stroke?
- Embolism
- Thrombosis
- Systemic hypoperfusion
- Cerebral venous sinus thrombosis
How can an embolism cause ischaemic stroke?
Embolus from another part of the body (e.g. heart) obstructs a cerebral vessel resulting in hypoperfusion
What condition can commonly lead to embolic ischaemic stroke?
AF
How does thrombosis lead to ischaemic stroke?
Local formation of a blood clot in a cerebral vessel
What is the most common cause of thrombosis leading to ischaemic stroke?
Rupture of an atherosclerotic plaque
How can systemic hypoperfusion lead to ischaemic stroke?
Systemic hypotension leads to reduced blood supply
When can systemic blood pressure drop low enough to cause systemic brain hypoperfusion leading to ischaemic stroke?
Cardiac arrest
How can cerebral venous sinus thrombosis lead to ischaemic stroke?
Blood clots form in the veins that drain the brain leading to congestion and hypoxia damaging brain tissue
When does haemorrhagic stroke occur?
When there is rupture of a blood vessel or abnormal vascular structure in the brain
What are the two subtypes of haemorrhagic stroke?
- Intracerebral haemorrhage
- Subarachnoid haemorrhage
What is an intracerebral haemorrhage?
Bleeding within the brain itself secondary to ruptured blood vessel
What are the subtypes of intracerebral bleed?
- Intraparenchymal
- Intraventricular
What is intraparenchymal bleeding?
Bleeding in the brain tissue
What is intraventricular bleeding?
Bleeding in the brain ventricles
What is a subarachnoid haemorrhage?
Bleeding that occurs outside of the brain tissue, between the pia mater and the arachnoid mater
What is the most common underlying cause of a subarachnoid haemorrhage?
Rupture of berry aneurysm
What are the three main (pairs of) arteries that supply the cerebrum?
- Anterior cerebral arteries
- Middle cerebral arteries
- Posterior cerebral arteries
What region of the cerebrum is supplied by the ACA?
Anteromedial area
What area of the brain is supplied by the MCA?
Lateral cerebrum
What area of the brain is supplied by the PCA?
Medical and lateral areas of the posterior cerebrum
What lobes of the brain are supplied by the ACA?
- Medial part of the frontal lobe
- Superior-medial parietal lobe
What lobes of the brain are supplied by the MCA?
- Lateral frontal lobe
- Lateral temporal lobe
- Lateral parietal lobe
What is the most common classification system used for ischaemic strokes?
Bamford classification (Oxford classification)
How does the Bamford classification categorise strokes?
Based on the initial presentation and signs
Does the Bamford classification require imaging?
No - it is purely clinical
What are the types of strokes in the Bamford classification?
- TACS
- PACS
- POCS
- LACS
What does TACS mean?
Total Anterior Circulation Stroke
What is a TACS?
A large cortical stroke affecting areas supplied by the ACA and MCA
What is the criteria for a TACS?
All three of:
- Unilateral weakness (or sensory deficit) of the face, arm and leg
- Homonymous hemianopia
- Higher cerebral dysfunction
What are some examples of higher cerebral dysfunction seen in TACS?
- Dysphasia
- Visuospatial disorder
What does PACS mean?
Partial Anterior Circulation Stroke
What is a PACS?
A less severe form of TACS where only part of the anterior circulation (ACA and/or MCA)
What is the criteria for a PACS?
Two of:
- Unilateral weakness (or sensory deficit) of the face, arm and leg
- Homonymous hemianopia
- Higher cerebral dysfunction
What does POCS mean?
POsterior Circulation Syndrome
What is a POCS?
Stroke involving damage to the area of the brain supplied by the posterior circulation (e.g. brainstem and cerebellum)
What is the criteria for a POCS?
One of:
- Cranial nerve palsy and a contralateral motor/sensory deficit
- Bilateral motor/sensory deficit
- Conjugate eye movement disorder
- Cerebellar dysfunction
- Isolate homonymous hemianopia
What is an example of a conjugate eye movement disorder that may be seen in a POCS?
Horizontal gaze palsy
What are some examples of cerebellar dysfunction that may present in a POCS?
- Vertigo
- Nystagmus
- Ataxia
What does LACS mean?
LACunar Syndrome
What is a LACS?
A subcortical stroke occurring secondary to small vessel disease
What does NOT occur in LACS?
Loss of higher cerebral function (e.g. dysphasia)
What are the criteria for LACS?
One of:
- Pure sensory stroke
- Pure motor stroke
- Sensori-motor stroke
- Ataxis hemiparesis
