Stroke Flashcards
What is stroke?
Development of focal or global neurologic deficit related to a vascular event
Are strokes always visible?
Yes
But ‘silent’ vascular events may occur
Describe the pathologic processes involved in stroke, and the percentage of patients in which they occur?
Infarction (75%)
Haemorrhage (20%)
Subarachnoid haemorrhage (5%)
What are the risk factors for cerebral infarction?
Ageing
Hypertension
Cardiac disease
Hyperlipidaemia
Diabetes Mellitus
Hypercoagulable states
Smoking
Obesity
What is cerebral infarction?
Necrosis of cerebral tissue in a particular vascular distribution due to vessel occlusion or severe hypoperfusion
What is the cause of cerebral infarction?
Usually related to arterial obstruction
Can also be arterioles, veins, heart
Describe the mechanisms of infarction?
Inadequate supply of blood due to pump failure
Inadequate supply of blood due to narrowed vessel lumen (atheroscelrosis, thrombosis, hypertensive vessel thickening, diabetes, amyloid angiopathy)
Vessel occlusion by embolus
Describe the causes of occlusion in vessels that cause cerebral infacrtion?
Large artery occlusion: thrombotic, may be embolic
Small vessel occlusion: thrombotic, may be embolic
Venous occlusion: thrombotic
Describe this pathology, and how it relates to stroke?
Valve vegetations
Due to non-bacterial thrombotic endocarditis
Vegetations can enter the systemic circulation
Describe this pathology, and how it relates to stroke?
Probe-patent interatrial septum
Potential for thrombus that form in venous system to pass from RA to LA, and then enter the brain
What is the most common site for thrombi to develop?
Venous system
Describe this pathology, and how it relates to stroke?
Atherosclerosis in Circle of Willis
Common sites: vertebral arteries, basilar artery, internal carotid termination artery, proximal middle cerebral artery
Describe this pathology, and how it relates to stroke?
Thrombotic vessel occlusion in atherosclerosis
Describe this pathology, and how it relates to stroke?
LEFT: old carotid endarterectomy
RIGHT: recent carotid endarterectomy
Procedure is performed to prevent ulcerated or stenotic atherosclerosis from causing cerebral infarction
Describe this pathology, and how it relates to stroke?
Swelling 36 hours after cerebral infarct
Due to cell membrane break down, accumulation of fluid and adjacent vasogenic oedema
Also herniation here
Describe how a brain looks immediately after cerebral infarction?
Initially, appears normal
Then starts to swell
Lose demarcation between grey and white matter
Herniation may occur
Describe this pathology, and how it relates to stroke?
Viable neurons centrally, surrounded by axonic-ischaemic neurons
Initally cells swell up, then neurons die, nucleus becomes pyknotic, and eventually disappears
Supporting glial cells have not died
Describe this pathology, and how it relates to stroke?
Infarct that is days/weeks old
Swelling has gone down
Tissue breaks down
Cerebral tissue necrotic - macrophages mving in to remove dead tissue
What is the pathology?
Liquefactive necrosis
Describe this pathology, and how it relates to stroke?
Infarct after months/years
Loss of cerebral tissue
Describe this pathology, and how it relates to stroke?
BRAIN: Cerebral haemorrhagic infarcts
Due to embolism from cardiac ventricle thrombus (small fragments of thrombus flicked up to brain)
HEART: Wall thinned, aneurysm of ventricle (can lead to thrombus)
What is haemorrhagic infarction charcteristic of?
Embolic events
Describe this pathology?
Haemorrhagic transformation in recent infarct
Describe this pathology, and how it relates to stroke?
Hyaline arterioloscelrosis
Most usually due to hypertension
Vessel balloons > enlargement of vascular lumen > can rupture> haemorrhage or thrombosis
Vascular disease can be at small vessel level such as this
Describe this pathology, and how it relates to stroke?
Old lacunar infarct
Small vessel occlusion > small infarct
May not be clinically important if in less important areas of brain
May be devastating if in important areas of brain
Why do people with cerebral infarction die?
Most commonly, die of complications due to them being incapacitated or having other risk factors: pneumonia, cardiovascular disease, pulmonary thromboembolism
May also die due to cerebral swelling or involvement of vital centres
Describe the possible complications of raised ICP?
Herniation
Brainstem haemorrhages
What are the causes of intracerebral haemorrhage?
Hypertensive small vessel disease
Congophylic (amyloid) angiopathy
Blood disorders
Tumour
Vasculitis
Vascular malformation
Drugs
Which vessels does amyloid angiopathy affect?
Small vessels
Much more likely to affect vessels at periphery of brain
What is the major cause of hypertensive haemorrhage?
Where does it usually occur?
Small vessel disease due to hyaline arteriolosclerosis
Usually occurs in basal ganglia/thalamus, lobar white matter, cerebellum or pons
Describe this pathology, and how it relates to stroke?
Intracerebral haemorrhage
Due to hyaline arteriolosclerosis
Also an old contralateral ‘slit’ haemorrhage
What is cerebral amyloid angiopathy?
Deposition of ab amyloid in walls of superficial supratentorial blood vessles
What disease states is cerebral amyloid angiopathy associated with?
Superficial haemorrhages
Alzheimer’s disease
Describe this pathology?
Amyloid angiopathy
Senile plaque left of centre
Thickening of walls of small vessels
Describe this pathology?
Multifocal synchronous haemorrhages
Due to coagulopathy
Must be a systemic problem, due to multifocal lesions
Describe this pathology?
Rupture of congenital ateriovenous malformation
Following attempted therapeutic embolisation
List the non-traumatic causes of subarachnoid haemmorhage?
Rupture of saccular/Berry aneurysm
Rupture of other types of aneurysm (mycotic, atherosclerotic)
Extension of intracerebral haemorrhage
Describe the risk factors for developing saccular aneurysm?
Gender - female
Age - in younger, not elderly
Polycystic kidney disease
Coarctation of aorta
Type III collagen deficiency
Hypertension
Smoking/alcohol
Describe this pathology?
Ruptured basilar artery due to saccular aneurysm
Where do saccular aneurysms usually occur?
Sites of congenital weakness at arterial bifurcations
More often in anterior circulation than posterior
Favoured sites: bi/trifurcation of MCA, junction of ICA and posterior communicating artery, anterior communicating artery
Describe this pathology?
Ruptured anterior communicating artery aneurysm
With inter and intraventricular haemorrhage
Describe the complications of aneurysm rupture?
How are they prevented?
Subarachnoid haemorrhage
Cerebral oedema and raised ICP
Vasospasm
Infarction
Hydrocephalus due to ventricular obstruction
Prevented by clipping neck of aneurysm to prevent further bleeding
