Pathology of Cerebrovascular Disease Flashcards
Where are large venous sinuses located?
Within the dura
What is meant by a focal neurological defecit?
Loss of function afecting a specific region of the central nervous system
What is a stroke?
Focal neurological defecit due to disruption of blood supply
What causes a stroke?
•Interruption of supply of oxygen and nutrients, causing damage to brain tissue
What causes interruption of supply of oxygen?
Changes in vessel wall (atheroma, vasculitis, outised pressure such as strangulation, spinal cord compression, compression of veins)
Changes in Blood flow and pressure (decreased blood flow, increased blood pressure bursting vessels)
Changes in blood constituents (thrombosis in arteries and rarely veins, reduced platelets and clotting factors causing bleeding)
What are the 3 main causes of localised interrupeted blood supply?
Atheroma and thrombosis - of artery causing ischaemia
Thromboembolism (for exampl, from left atrium) causing ischaemia
Ruptured aneurysm of a cerebral blood vessel casusing haemorrhage
What are the components of a thrombus?
There are two components to athrombus: aggregated platelets and red blood cells that form a plug, and a mesh of cross-linked fibrin protein.
What is the result of an interrupted blood supply in the internal carotid artery?
Typically get ischaemia in the middle cerebral artery area (but can also affect elsewhere)
What does it mean if the focal neurological defecit only lasts less than 24 hours?
Reversible ischaemia
TIA
Tissue is still viable
What does it mean if the symptoms last longer than 24 hours?
Irreversible ischaemia
Stroke
Infarction of tissues
What type of damage is caused to the neurones in infarction?
Leads to permanent neurone damage
Neurones do not regenerate
What is the shape of regional cerebral infarct caused by atheroma and thrombosis?
Wedge shaped - reflects arterialperfusion territory
Soft and then it becomes cystic
What is gliosis?
CNS equivalent of fibrosis
Foamy macrophages - repair process
Why does blood flow in the circle of willis tend to stay the same?
Arteries in the circle of willis tend not to have muscular walls
Artery walls are thin and weakening of the wall in conjunction with hypertension causes aneurysms to form
What are the common haemorrhaic sites for hypertensive patients?
Basal ganglia - microaneurysms
Circle of willis - berry anneurysms
What area of the brain is well perfused when there is hypotension?
What areas of the brain are poorly perfused during hypotenison?
Watershed zones - Periphery of zone is less well supplied – on post mortem – zonal pattern of ischaemia and infarction at interface territories (watershed infarcts)
