Flashcards in Neuropathology Deck (88)
What can cells of the CNS be damaged by?
Lack of oxygen (hypoxia/anoxia)
What occurs in hypoxia damage to CNS?
Neurones are most vulnerable-have selective vulnerability
Activation of glutamate receptors-results in uncontrolled calcium entry into the cell
Neurones can't use anaerobic glycolysis
What is an axonal reaction?
A reaction within the cell body that is associated with axonal injury
What is the response to axonal injury in neuronal degeneration?
Increase RNA and protein synthesis
Swelling of cell body
Peripheral displacement of nucleus
Enlargement of nucleolus
Anterograde degeneration of axons occurs distal to site of injury
Breakdown of myelin sheath
What occurs in damage to astrocytes?
Reactive response associated with proliferation (gliosis)
Leads to cell death or degeneration
What occurs in gliosis?
Astrocytes undergo hyperplasia and hypertrophy
Nucleus enlarges, becomes vesicular and nucleolus is prominent
Cytoplasmic expansion with extension of ramifying processes
What is the most important histopathological indicator of CNS injury regardless of cause?
What happens to old lesions in gliosis?
Nuclei become small and dark and lie in a dense net of processes (glial fibrils)
What is injury to oligodendrocytes a feature of?
What do ependymal cells line?
The ventricular system
What is disruption to ependymal cells associated with?
A local proliferation of sub-ependymal astrocytes to produce small irregularities on the ventricular surfaces termed ependymal granulations
How do microglia respond to injury by?
Developing elongated nuclei (rod cells)
Forming aggregates about small foci of tissue necrosis (microglial nodules)
Congregate around portions of dying neurons (neuronophagia)
How is blood supplied to the brain?
Via branches of the internal carotid and vertebral arteries which forms the anterior and posterior circulations
What occurs in anterior cerebral artery pathology?
Frontal lobe dysfunction
Contralateral sensory loss in foot and leg
Paresis of arm and foot, relative sparing of thigh and face
What occurs in middle cerebral artery pathology?
Dominant vs non-dominant effects
What does the posterior vertebrobasilar artery supply?
What can damage to the brainstem due to ischaemia cause?
Midbrain- Weber's syndrome
Pons- Medial & lateral inferior pontine syndromes
Medulla- Lateral medullary syndrome
What can ischaemia to the occipital lobe cause?
Homonymous hemianopia with macular sparing
What is more vulnerable to hypoxic ischaemic damage, neurons or glial?
What are watershed areas?
Junctions of arterial territories (arterial border zones)- they are first to be deprived of blood supply during hypotensive episodes
What are some of the watershed areas?
Superior cerebral convexities at the junctions of the anterior and middle cerebral arteries, and the posterior aspects of the cerebellar hemispheres at the junction of the territories supplied by the superior and posterior inferior cerebellar arteries.
What is the definition of a stroke?
Sudden disturbance of cerebral function of vascular origin that causes death or lasts over 24 hrs
What is the most common type of stroke?
What are the two types of strokes?
Haemorrhage- Intracerebral, subarachnoid, bleeding into infarct
What is the most common type of haemorrhage stroke?
Where does a thrombotic stroke most commonly occur?
At the bifurcation of the common carotids or in basilar artery
Where does an emboli causing an embolic stroke usually originate?
From the heart of atherosclerotic plaque in more proximal arterial segments
Where do most embolic occlusions occur?
In the branches of the middle cerebral arteries
What are the RFs for a stroke?
Serum lipids, obesity, diet
Diseases of neck arteries