Pathology of Cerebra-Vascular Disease Flashcards
what cerebral artery supplies the largest area of brain?
the middle cerebral artery
in what area of the brain does the middle cerebral artery divide into two ?
at the sylvain fissure
what area of the brain does the middle cerebral artery supply?
as if putting your hands on the side of your head on the outside of the brain
what area of the brain does the anterior cerebral artery supply?
mostly the medial surface anteriorly and suppling posteriorly until the parieto-occipital sulcus
what area of the brain does the posterior cerebral artery supply?
inferior of the temporal lobe and the occipital lobe posteriorly
do veins in the brain follow arteries?
no
between what two layers are the venous sinuses ?
between the dural folds
what do all the venous sinuses drain into ?
the internal jugular vein
what are the veins called which connect the intracranium and extrcranium ?
emissionary veins
what is the WHO definition of a stroke?
Focal neurological deficit (loss of function affecting a specific region of the central nervous system) due to disruption of its blood supply
what are the two types of strokes?
ischaemic
haemorrhagic
what type of stroke is the most common?
ischaemic stroke
what are the major symptom of a stroke?
sudden weakness or numbness
often one side of the body is affected
other symptoms which are experienced by the stroke patient is dependant on what?
the area of brain affected
what other symptoms as well as weakness are often seen in stroke patients ?
confusion difficulty speaking/understanding speech difficulty walking difficulty seeing severe headache unconsciousness
what are the three major categories of stroke /
Transient ischaemic attack (TIA)
Minor stroke
Disabling stroke
what is a TIA?
Symptoms and signs last <24hr
what is a minor stroke?
> 24hr but minor neurological deficit
what is a disabling stroke?
> 24hr with persisting disability that impairs independence such as Not being able to swallow
is the brain sensitive to changes in oxygen ?
yes very sensitive
what percentage of cardiac output does the brain get?
15%
what are the two complications of hypoxia which causes ischaemia?
- infarction
2. permanent damage to the neurones
what drug can be used for about 85% of stroke patients ?
thrombolysis
what are the three components of virchows triad?
- change of vessel wall
- change in blood composition
- change in flow
what is ischaemia ?
reduced or absent oxygen in a tissue or organ
what is Poisseuille’s law a measurement of ?
flow
what three variables are present in Poisseuille’s law
which determines flow?
pressure gradient x radius ^4 / 8 length
if the pressure gradient decreases in Poisseuille’s law what happens to the flow ?
decreases
if the radius decreases in Poisseuille’s law what happens to the flow ?
radius decreases, resistance increases, therefore flow decreases
if the length of the vessel decreases in Poisseuille’s law what happens to the flow ?
length decreases, the flow will increase
what is the mechanism called when the vessels change their radius to maintain the same cerebral blood flow ?
autoreguation
give examples of the different types of flow in a vessel ?
stagnant
laminar
turbulent
give 8 causes of ischaemia ?
atherosclerosis thrombosis embolism hypotension arterial spasm
systemic vascular disease (arteritis)
mechanical compression
venous obstruction
how does arterial spasm cause ischaemia ?
spasm causes a decrease in vessel radius therefore the blood flow to the brain is reduced
when would arterial spasm occur in the brain?
after a subarachnoid haemorrhage
give two arteries where infarction commonly occurs?
internal carotid artery
middle cerebral artery
what are the two most common locations in the brain for ischaemia to occur ?
cerebral hemispheres
internal capsule
what symptom is caused by infarction in the internal capsule ?
contralateral hemiparesis
which cells are very vulnerable to die following ischaemia?
neurones
what shape is the infarction following ischaemia?
wedge shaped
- reflecting the arterial perfusion territory
what does the brain look like after an infarction?
soft and becomes cystic
what is regeneration of the brain following infarction called?
gliosis
- equivalent of fibrosis
state three risk factors of thrombotic stroke?
arteriosclerosis
smoking
diabetes
what two conditions could be the source of an embolism causing a stroke?
cardiac arrhythmias
thoracic aortic aneurysm
what is a watershed infarction ?
Periphery of perfusion territory of major arteries especially affected
- the borders between the artery territories
what is the law which determines flow in a vessel?
Poisseuilles law
neurones in which part of the brain are most sensitive to hypotensive events?
superficial cortex, hippocampus, thalamus, cerebellum
what three things would be seen in the histology of an infarct ?
loss of neurones
foamy macrophages
gliosis
what do foamy macrophages do?
they are involved in the repair process leading to gliosis
what is the definition of a haemorrhagic stroke ?
Rupture of a small artery usually at a bifurcation leading to catastrophic haemorrhage
are hemorrhagic strokes more common than ischaemic strokes?
no
in which location do haemorrhagic strokes usually occur ?
at bifurcations of arteries
state some risk factors of hemorrhagic stroke ?
systemic HT
over 50yrs
what is a common location effected by haemorrhagic strokes?
basal ganglia
then
- brain stem
- cerebellum
- cerebral cortex
what is the aneurysm called which is seen in subarachnoid haemorrhages ?
saccular (Berry) aneurysm
which part of the circle of willis is most commonly affected by a subarachnoid haemorrhage ?
the anterior part
- internal carotid
- anterior communicating
- middle cerebral
what size are most aneurysms for SAH?
<10mm
in which age range are inter ventricular haemorrhages most common?
in babies and infants
what is the prognosis of interventicular haemorrhages ?
very poor outcome
what causes inter ventricular haemorrhages ?
hypoxia in premature infants
after an intracranial haemorrhage what changes occur in the brain tissue?
the tissue can become cystic
what are the complications of intracranial haemorrhages?
rapid increase of ICP
death
what is a stroke ?
stroke is a neurological deficit caused by disruption of blood supply
what is the appearance of an ischaemic stroke ?
wedge shaped infarction
- usually the middle cerebral artery
what area of the arteries are commonly affected by haemorrhagic strokes ?
the bifurcation
state some causes of ischaemic strokes?
atherosclerosis thrombosis embolism hypotension arterial spasm systemic vascular disease
state some causes of haemorrhagic strokes ?
aneurysm
trauma
hypertension
