Cerebrovascular Diseases Flashcards
What is a Stroke?
A brain disease due to vascular pathology
What conditions/diseases are commonly associated with a stroke?
Atheroma,diabetes and hypertension
What are the two vascular pathologies that lead to a stroke?
1.Infarcation
2.Hemorrhage
What is an infarction?
Critical reduction in arterial oxygenation.
Name three types of an infarction?
1.Thrombotic
2.Embolic
3.Hypotensive
Name two types of a hemorrhage?
1.Intracerebral
2.Subarachnoid
What two problems lead to hypoxia and the type of hypoxic damage caused?
1.Major fall in BP or a systemic hypoxia causing a diffuse damage.
2.Vessel blockage causing focal damage.
In diffuse hypoxic damage,what does the damage depend on?
Severity and duration of hypoxia.
Which neutrons are susceptible to a diffuse hypoxic damage?
1.Neurons in the hippocampus
2.Purkinje cells
3.Neurons in the cerebral cortex
What happens to the brain in the case of a diffuse hypoxic damage?
It becomes oedematous,raising ICP
Effects of diffuse hypoxic damage?
Anything from mild confusion through PVS( Persistent vegetative state) to immediate death.
What causes both diffuse and Focal hypoxic damage?
Acute hypotension
Which areas are affected when acute hypotension causes focal damage?What kind of infarcts does it cause?
1.Watershed infarcts
2.Between the anterior cerebral and middle cerebral artery
What does a focal hypoxic damage depend on?
On the presence of collaterals
Where on the brain do collaterals exist?
1.On the surface e.g Circle of Willis BUT not within the brain.
What causes a focal hypoxic damage?
By a focal vascular abnormality from:
1.Thrombosis
2.Embolism
What do the clinical effects due to a focal hypoxic damage depend on?
1.Site
2.Extent and Speed of onset of vascular block
Thrombotic cause of focal hypoxia?
Atheroma
In which arteries does thrombosis normally occur?
1.Carotid birfurcation
2.Origin of middle cerebral artery
3.Origin of basilar artery
What are the different types of embolisms that can cause a focal hypoxic damage? And which one is the most common.
- cardiac mural thrombi(commonest)
2.arterial thromboemboli
3.paradoxical emboli
4.Emboli of other material (tumour, fat, marrow, air)
In which conditions do cardiac mural thrombi occur?
1.Myocardial infarction
2.Valvular diseases
3.Atrial Fibrillation
What is the most common cause of an arterial thromboembolism occurring?
Carotid plaques
Which group of people are affected by paradoxical emboli?
Children with cardiac anomalies
Which artery is mostly affected in the case of a cerebral embolism?
Middle cerebral artery territory
Where do emboli normally lodge?
At Branches or Stenoses
What kind of embolism occur after fractures?
Shower embolism of fat.
Effects of shower embolism of fat?
They cause capillary blockages which disturb higher cortical functions and consciousness (often with no localising signs)
Characteristic of a bone marrow embolism?
Widespread hemorrhagic lesions of white matter.
How are cerebral infarcts classified? And what does the classification depend on?
1.Red or pale
2 Depends on presence or absence of haemorrhage from infarcted vessels
Where do venous infarcts usually occur?
Beside sinuses
What are venous infarcts associated with?
1.infection
2.dehydration
3. drugs (especially oral contraceptives)
What are the microscopic changes that occur in an infarct?
1.increased eosinophilia of neurons
2.then neuronal death and cell infiltrate
3.eventual gliosis
Which type of emboli shows petechial haemorrhages?
Bone marrow
What is the most common cause of a subarachnoid haemorrhage?
A cerebral artery berry(saccular ) aneurysm
What are the other causes of a subarachnoid haemorrhage?
1.Extension from a intracerebral haemorrhage
2.Vasculitis
3.bleeding diseases
4.Trauma
5.Tumour
Where do Berry Aneurysms normally occur?
Occur near the major branch points of the Circle of Willis
More common on the anterior part of the circle of Willis.
Describe berry aneurysms?
thin-walled out-pouching
usually < 1 cm diameter
wall consists usually only of intima
Which part of the berry aneurysms bursts?And where does the blood flow into?
1.rupture at apex
2.usually into subarachnoid space, but sometimes into brain or both
Causes of berry aneurysms?
- Genetic factors
Predisposing factors of berry aneurysms?
Cigarette smoking and hypertension are predisposing factors
Around which age do berry aneurysms burst?
40-50s
What may precipitate a berry aneurysm?
A sudden rise in ICP or BP
What are the effects of the rupture of a berry aneurysm on the patient?
1.Sudden severe headache and rapid loss of consciousness
2.10-15%die
3.Most recover consciousness in minutes
4.The patient may show meningism
5.Rebleeding is common making the prognosis worse.
What are the early effects of a Subarachnoid haemorrhage.
increased risk of vasospasm of other vessels due to vascular mediators
which can lead to additional ischaemic injury, espec. if spasm involves Circle of Willis
Late sequelae due to subarachnoid haemorrhage?
Meningeal scarring and fibrosis
Possible obstruction of CSF flow/reabsoprtion
Describe the colour of subarachnoid haemorrhage?
initially it is bright red blood
later, yellow colour when the red cells degenerate.
Other names for an intracerebra haemorrhage?
Parenchymal haemorrhage
cerebral haemorrhage
What are intracerebral associated with?
Hypertension
Besides hypertension what are the causes of intracerebral hypertension?
1.Vascular malformations
2.Bleeding diseases
3.Vasculitis
4.Angiomas
5.AV malformations
What structures of the brain are affected during an intracerebral haemorrhage?
Basal ganglia
brainstem
cerebellum
cerebral cortex
Where can intracerebral haemorrhages extend into?
Ventricles and or subarachnoid space
What surrounds the hematoma seen in survivors of an intaerebral haemorrhage?And how is the hepatoma repaired?
1.It is surrounded by a zone of reaction
2.then repair with gliosis
What is the importance of hypertension in CVD?
Common cause of CVD
What is hypertension frequently associated with?
Atheroma and diabetes
In terms pf CVDs,what is hypertension responsible for?
1.intracerebral hemorrhages
2.Rupture of berry aneurysms, so subarachnoid haemorrhages
3.Lacunar infarcts
4.Hypertensive encephalopathy
How does hypertension cause lacunar infarcts?
Hypertension causes arteriosclerosis which with or occlusion of vessels supplying basal ganglia, hemispheres and brainstem causes single/multiple small cavitated infarcts.
Describe the infarcts?
Consists of tissue loss with scattered compound granular corpuscles surrounded by gliosis
What do clinical effects of lacunar infarcts depend on?
Location of the infarct
they could be silent
Define Acute hypertensive encephalopathy?
syndrome of diffuse cerebral dysfunction
What are the signs/symptoms of acute hypertensive encephalopathy?
headaches, confusion, vomiting and convulsions, sometimes leading to coma
What is acute hypertensive encephalopathy usually a part of?
Accelerated (malignant)phase hypertension
Why is rapid treatment needed in acute hypertensive encephalopathy?
In order to reduce raised ICP
Effects of acute hypertensive encephalopathy on the brain.
oedematous brain +/- tentorial or tonsillar herniation
arteriolar fibrinoid necrosis and petechiae throughout brain
What is chronic hypertensive encephalopathy a cause of?
vascular (multi-infarct) dementia
What is Vascular dementia?
dementia often with focal neurological defects
What causes chronic hypertensive encephalopathy?
By multifocal vascular disease over long time
Examples of multifocal vascular diseases/
cerebral atheroma
thrombosis or embolism from carotids or heart
cerebral hypertensive arteriolosclerosis
Common cause extradural and subdural haemorrhage?
Trauma
What are extradural and subdural haemorrhages
almost always due to?
Trauma
COMPARETHE MAJOR CAUSES OF STROKE.
LIST :
Clinical presentation
30-day mortality %
Pathogenesis
Predisposing factors
Refer to the table in HANDOUT.
Compare the following between a subarachnoid hemorrhage and intracerebral hemorrhage:
1.Cause
2.signs +symptoms
3.location in brain
4.Side effects of hemorrhage.
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