Cerebrovascular Disease Pathology Flashcards
Which cerebral vessel is most commonly affected in thromboembolic disease, mainly because of its position?
MCA
What is the important overlying process which can result in both ischaemic and haemorrhagic strokes?
Hypertension
What is global hypoxic ischaemic damage?
When the systemic compromise to circulation (e.g. cardiac arrest, hypovolaemic shock) cannot be compensated for by CNS autoregulatory mechanisms
Global hypoxic ischaemic damage occurs when MAP reaches what level? What is the significance of this?
50mmHg - this is when autoregulatory mechanisms cannot sufficiently compensate
What are watershed areas?
Areas at the peripheries of vascular territories
Why do watershed areas contain neurones which are particularly sensitive to hypoxia?
Because they are the most distant from the heart, and the least well supplied
Which type of cell found in the CNS is more sensitive to hypoxic damage - neurones or glial cells?
Neurones
What is focal ischaemia?
Restriction of blood flow to a localised area of the brain, typically due to a vascular obstruction
The presence of atheroma in both intra and extra cerebral blood vessels is a risk factor from stroke. Atheroma can affect all the main cerebral arteries but in general, which is most commonly affected?
Basilar artery
Atheroma formation in the extracranial vessels (e.g. carotids and aorta) is significant as these are the source of the majority of which type of stroke?
Embolic
Describe why hypertension is a risk factor for both ischaemic and haemorrhagic stroke?
Ischaemic - contributes to atheroma formation and atherosclerosis Haemorrhagic - increases the chance of spontaneous rupture of vessels
In an ischaemic stroke, after how long will the necrotic area become visible macroscopically?
48 hours
After an ischaemic stroke, what will always remain macroscopically as a permanent marker of the site of an old infarction?
Gliotic scar to start with which will desist to become a cystic gap
Microscopically, what is the primary cell type seen within 48 hours of an ischaemic stroke?
Neutrophils
Microscopically, what is the primary cell type seen after 48 hours of an ischaemic stroke?
Microglia
Around a week after an ischaemic stroke, what pathological process takes place microscopically? What happens?
Reactive gliosis - astrocytes increase in number and size
A few weeks after an ischaemic stroke, a cavity begins to form microscopically which is lined by what?
Gliotic scar tissue characterised by astrocytes
Give some examples of types of intracranial haemorrhage which can occur due to trauma?
Extradural haematoma, subdural haematoma, contusion
What is the commonest cause of spontaneous intracerebral haemorrhage?
Rupture of small cerebral blood vessels (perforating arteries) with walls weakened by hypertension
Hypertension is the most common cause of spontaneous intracerebral haemorrhage, what are some others?
AVM, amyloid angiopathy, aneurysm rupture, tumours, clotting dysfunction
Intracerebral haemorrhage is most likely to occur in which 4 locations?
Basal ganglia, thalamus, cerebral white matter, cerebellum
What is the most common cause of a subarachnoid haemorrhage?
Rupture of a saccular (Berry) aneurysm
90% of Berry aneurysms are seen in the territory of which artery?
Internal carotid artery
10% of Berry aneurysms are seen in the territory of which arterial system?
Vertebro-basilar circulation
Where in the internal carotid artery are Berry aneurysms most likely to be found?
At the arterial bifurcations at the Circle of Willis
Because of the high pressure involved or because of the location of vascular lesions, subarachnoid haemorrhage may be associated with what?
Intracerebral haemorrhage
What are some examples of mass effect which may be seen with subarachnoid haemorrhage?
Features of oedema, raised ICP
Describe the relationship between subarachnoid haemorrhage and hydrocephalus?
Acute hydrocephalus will develop within the first few days, then the chronic type will develop around the second week due to obstruction of flow of CSF in the subarachnoid space
Vasospasm can occur as a result of subarachnoid haemorrhage. This brings around vasoconstriction which can lead to what?
Secondary brain ischaemia and infarction
What are the three main risk factors for subarachnoid haemorrhage?
Smoking, hypertension and kidney disease
What is the typical presentation of a subarachnoid haemorrhage?
Thunderclap headache, vomiting and loss of consciousness
What is the outcome of subarachnoid haemorrhage?
50% die within several days of onset, survivors are at risk of hydrocephalus
Subarachnoid haemorrhage is more common in which gender? And what age group
Female, usually before the age of 50
There is a higher incidence of subarachnoid haemorrhage in patients with what conditions?
Polycystic kidney disease (or known Berry aneurysm), fibromuscular dysplasia, coarctation of the aorta, AVM
Hypertensive encephalopathy occurs in severely hypertensive patients - what is this?
When the upper limit of autoregulatory mechanisms is saturated the BBB becomes incapable of resisting movement of plasma proteins into the brain which leads to vasogenic oedema and symptoms of raised ICP
Chronic hypertension is associated with the development of what? Where do these most commonly occur?
Micro-aneurysms which occur particularly in small branches of the MCA most commonly in the basal ganglia
Microaneurysms which develop as a result of chronic hypertension increase the risk of what?
Intracerebral haemorrhagic stroke
Which vessel supplies the area in blue?
Anterior cerebral artery
Which vessel supplies the area in pink?
Middle cerebral artery
Which vessel supplies the area in green?
Posterior cerebral artery
Which vessel supplies the area in blue?
Anterior cerebral artery
Which vessel supplies the area in yellow?
Middle cerebral artery
Which vessel supplies the areas in red?
Posterior cerebral arteries
Which vessel supplies the area in green?
Anterior choroidal artery
