Neuropathology Flashcards
Name some general types of neuropathology.
Infections in the CNS
Prion disease
Pathology of dementia
Raised ICP
Brain tumours
Head trauma
Stroke
What are the three possible routes via which microorganisms can gain entry to the CNS? Give examples.
Direct spread e.g.middle ear infection, basilar skull fracture
Blood-bourne e.g.sepsis, infective endocarditis
Iatrogenic- V-P shunts, surgery, lumbar puncture
Meningitis is inflammation of which structure?
Leptomeninges
Give the causative agents of meningitis at each of these stages of live:
Neonatal
2-5 years
5-30 years
>30 years
Neonates: E.Coli, Listeria monocytogenes
2-5 years: Haemophillus influenza type B
5-30 years: Nisseria meningitides
30+: Steptococcus pneumoniae
How is chronic meningitis defined?
What is the most common causative organism?
Inflammation of the leptomeninges for 1 month or more. Mycobacterium Tuberulosis
Which three pathological features occur during chronic meningitis?
Granulomatous inflammation
Fibrosis of meninges
Nerve entrapment
List some of the complications of meningitis.
Which of these outcomes is most common?
- Death- most common
- Cerebral infarction
- Cerebral abscess
- Subdural empyema
- Epilepsy
What is encephalitis?
What is its pathogenesis?
Infection of the brain parenchyma
Neuronal cell death by virus
Which areas of the CNS are effected by each of the following viruses?
Herpes
Polio
Rabies
Herpes- temporal lobe
Polio- spinal cord motor neurones
Rabies- brain stem
What are some of the presenting symptoms of cytomegalovirus?
Headaches
Nausea
Vomiting
Photophobia
How is cytomegalovirus treated?
Supportively
How does cytomegalovirus infection look microscopically?
“owl eyes” Virions replicating in the cells
How do mutated prion proteins (PrPs) cause disease?
Mutated PrP interacts with normal PrP to undergo a post-translational, conformational change.
These proteins clump together and cause cell death and holes in grey matter.
Why can prion disease not be classed as an infection?
It does not fulfil Koch’s postulates
Define dementia. How does this compare to delirium?
Acquired global impairment of intellect, reason and personality without impairment of consciousness.
Delirium involves changes in consciousness and is usually rectified when the underlying cause is treated, whereas dementia is progressive.
What is normal ICP?
What value does this rise to during coughing/straining?
0-10mmHg
20mmHg
Which compensation mechanisms are able to maintain normal ICP?
Reduced blood flow
Reduced CSF volume
Spatial reduction- brain atrophy
Vascular mechanisms maintain cerebral blood flow as long as ICP is _______ than __________.
Less than 60mmHg
An expanding/space occupying lesion of the brain results in what?
Deformation or destruction of the brain around the lesion
Displacement of midline structures
Brain shift—> herniation
bralWhat are the three types of cerebral herniation?
Explain how they each differ.
Use a diagram to mark them on.
- Subfalcine herniation
Same side as mass, cingulate gyrus pushed under free edge of flax cerebri
- Transtentorial herniation (down or up)
Uncus pushed through the tentorial notch
- Tonsilar herniation
Cerebellar tonsils pushed into foramen magnum compressing the brainstem
What are the clinical consequences of subfalcine herniation?
Ischaemia of medial parts of the frontal and parietal lobe and corpus callosum due to compression of anterior cerebral artery.
—> infarction
What are the clinical consequences of transtentorial herniation?
Damage to the occulomotor nerve (on the same side)
Occlusion of blood flow in posterior cerebral and superior cerebellar arteries
Secondary haemorrhage into the brainstem—-> DURET HAEMORRHAGE—-> Death
Are CNS tumours most common in adults or children?
Why?
Children
Very rare in adults once the nervous system is established, not much dividing potential so not much chance of mutation leading to neoplasm.
What is the name given to a benign tumour of meningeal origin?
Meningioma
What are the two broad categories of stroke with % occurance of each?
Cerebral infarction 85%
Cerebral haemorrhage 15%
What are the types of infarct?
How do they differ?
Regional - named cerebral artery or carotid
Lacuna - 1cm, associated with hypertension, commonly affect the basal ganglia
What are Charcot-Bouchard aneurysms?
What condition are they associated with?
Micro-aneurysms within the brain parenchmya
Hypertension
Subarachnoid haemorrhage is associated with rupture of which structures?
Where are the usually found?
“Berry” aneurysms
Branching points in the Circle of Willis
What is a key symptom that marks the occurance of subarachnoid haemorrhage?
Thunderclap headache
“worst headache of life”
