T1 L19: Neuropathology Flashcards
What are the 3 layers of meninges?
Dura mater - Firmly attached to the skull
Arachnoid - Net-like connective tissue containing vessels
Pia mater - Covers the whole brain
What are the causes hydrocephalus?
Obstruction
Impaired resorption at arachnoid granulations
Shrinking of brain tissue
Over production
What is hydrocephalus ex vacuo?
Shrinking of brain Eg. Dementias
What are the 3 areas where brain herniations occur?
Subfalcial (cingulate)
Central (transtentoral)
Tonsillar (cerebellar)
Which type of brain herniation is the worst and why?
Tonsillar (cerebellar) herniation because it causes compression of the medulla with impairment to vital respiratory and cardiac functions
What is a Duret haemorrhage?
A haemorrhage caused by herniation of the brain
It’s deadly
Why should a lumbar puncture not be performed when someone has suspected raised intracranial pressure?
Because it can cause a tonsillar herniation when the pressure is relieved so quickly
(The brain is squished into the magnus)
What are some cases of space occupying lesions?
Extradural/ epidural haemorrhage Subdural haemorrhage Subarachnoid haemorrhage Intracranial haemorrhage Ischaemic infarct with subsequent oedema or haemorrhage Neoplasm Abscess
What is a diffuse axonal injury?
A very high impact injury causing all electrical energy to be knocked out
Why is there no countercoup when the head is stationary?
Because the moving object wont produce enough inertia if the head is stationary
What is the extradural space and what type of haemorrhage occurs here?
The space between the skull and the dura. This space is small so only arterial pressure can cause the bleed meaning it has to be a severe injury
Who is most likely to get a subdural bleed?
Old people because it’s caused by a broken vein. In older people they veins loose their elasticity so they are more likely to break with a fall
Which artery causes a extradural bleed?
The Middle meningeal artery
If someone has an injury but feels fine and then collapses later, which artery has burst in this injury?
The MMM. This person would die because of the build up of pressure
What shape does a extradural bleed cause?
A ‘C’ shape along the border of the brain
What shape does a subdural bleed cause?
A lemon shaped because the brain is deformed due to the pressure build up. Its an old bleed
Which type of haemorrhage is associated with berry aneurysms?
A subarachnoid (subdural) haemorrhage
What is a vasogenic cerebral oedema?
Increased vascular permeability caused by a disruption to the blood-brain barrier
What is a cytotoxic oedema?
A neuronal, glial, or endothelial cell damage. Cells expand instead of expanding the extracellular space
Why is ischaemia worse than hypoxia?
Because there is a build up of toxic metabolites that destroys cells. People tend not to die of hypoxia
Which type of necrosis does an ischaemic infarct cause>
Liquefactive necrosis - the brain matter is destroyed and becomes jelly
What are some histological features of ischaemic infarcts in the brain?
'red neurones' Pyknosis of nucleus Shrinkage of the cell body Intense eosinophilia of cytoplasm Liquefactive necrosis
What is Pynosis?
The irreversible condensation of chromatin in the nucleus of a cell undergoing necrosis or apoptosis
Give examples of some peripheral nerve sheath tumous
Schwannoma
Neurofibroma
MPNST
