Pathology of Cerebrovascular Disease Flashcards
what is a stroke?
Focal neurological deficit due to disruption of its blood supply
reduction in oxygen and nutrients cause damage to brain tissue
what is a focal neurological deficit?
loss of function affecting a specific region of the central nervous system
what is the most common type of stroke?
(85%) result from a blood vessel being blocked by a thrombus – ischaemic stroke
what is the less common type of stroke?
Around one in ten strokes arise from a ruptured blood vessel causing a haemorrhage
what are the symptoms of a stroke?
Sudden weakness or numbness - face, arm etc (usually unilateral)
confusion-difficulty speaking/understanding speech
difficulty seeing
difficulty walking, dizziness, coordination loss
severe headache
Unconsciousness
what is a Transient ischaemic attack (TIA)?
Symptoms and signs last <24hr
what is a Minor stoke?
> 24hr but minor neurological deficit
what is a Disabling stoke?
> 24hr with persisting disability that impairs independence
what brain damage can a few minutes of hypoxia or anoxia cause?
brain ischaemia
Can lead to infarction
Damage to neurones is permanent
Neurones do not regenerate
what are 85% of strokes treated with?
thrombolysis
what are causes of CNS ischaemia?
Atherosclerosis Thrombosis/Embolism Hypotension Cardiac arrest Massive blood loss Arterial spasm following subarachnoid haemorrhage Systemic vascular disease Mechanical compression Venous obstruction
when does cerebral infarction occur?
Blockage to major artery most within internal carotid artery (especially middle cerebral artery)
which parts of the brain are most affected by acute cerebral cortex ischaemia?
Cerebral hemispheres, internal capsule (most common)
Contralateral hemiparesis
Neurones die fast; supportive (glial) tissues are more robust
Lose grey-white matter definition
what are the underlying causes of thrombotic stroke?
arteriosclerosis, smoking, diabetes
what are the underlying causes of embolic stroke?
cardiac arrhythmia, thoracic aortic aneurysm
what is Watershed” infarction?
occur at the border between cerebral vascular territories where the tissue is furthest from arterial supply and thus most vulnerable to reductions in perfusion
(Area 7 most at risk)
what parts of the brain are most sensitive to global ischaemia?
Neurones in the superficial cortex, hippocampus, thalamus, cerebellum
what is global ischaemia?
occurs when blood flow to the brain is halted or drastically reduced
commonly caused by cardiac arrest
MAP less than 60mmHg systolic is risk
what is the CNS equivalent of fibrosis?
Loss of neurones causes foamy macrophages –repair process leading to GLIOSIS
what is the pathogenesis of a haemorrhagic stroke?
Rupture of a small artery usually at a bifurcation leading to catastrophic haemorrhage
describe an Intracerebral haemorrhage
Associated with systemic hypertension in over 50s
80% of these in basal ganglia
Brainstem, cerebellum, cerebral cortex
what is the most common cause of non-traumatic subarachnoid haemorrhage?
Rupture of saccular (Berry) aneurysm on circle of Willis
where in the circle of willis is a Subarachnoid haemorrhage most likely to occur?
Branching points of on the anterior part of the circle of Willis
Internal carotid, anterior communicating artery and middle cerebral artery most common
what is the average size of a Subarachnoid haemorrhage?
Mostly <10mm but up to 50-60 mm seen
Contain thrombus so imaging can underestimate true size
what is an infantile Interventricular haemorrhage?
Hypoxia in premature infants
Babies in NICU
Poor outcome
what are the consequences of an intracranial haemorrhage?
Death because of rapid increase in intracranial pressure – especially subarachnoid
Clinical features of stroke
Headache especially in subarachnoid
Secondary infarction – local effect of mass lesion and ICP effect
Long-term survivors lose brain tissue – cystic
