Neuro14 - Pathology of the Brain

Question 1

3 features of encephalitis

Definition
Pathophysiology
Common Viruses x3

Answer 1

1. ) Definition - inflammation of the brain parenchyma often caused by a viral infection
   - can occur as a complication of meningitis
2. ) Pathophysiology - virus kills neurones —> inflammation and intracellular viral inclusions
   - often also get lymphocytic infiltrate
3. ) Common Viruses
   - herpes viruses: affects the temporal lobe (common)
   - polio: affects the spinal cord (now eradicated)
   - rabies: affects the brainstem (very rare)

Question 2

4 features of prion diseases

Prion Protein (PrP)
PrPsc
PrPsc Damage
Spongiform Encephalopathies

Answer 2

1. ) Prion Protein (PrP) - normal protein found in synapses
   - unknown function
2. ) PrPsc - abnormal isoform of prion proteins (due to sporadic mutation, familial inheritance or ingestion of the protein itself)
   - produces more PrPsc from PrP
   - extremely stable (resistant) and not susceptible to immune attack as its essentially a ‘self’ protein

4.) PrPsc Damage - forms aggregates which destroys neurones, causing the brain to take on a spongiform appearance

5. ) Spongiform Encephalopathies - group of progressive, fatal conditions associated with prion proteins
   - causes psychiatric problems (inc dementia) and painful sensations
   - scrapie in sheep, mad cow disease (BSE)
   - variant Creutzfeld Jacob Disease (vCJD) is caused by ingestion of BSE and associated w/ earlier age death

Question 3

4 types of brain tumours

Meningioma
Astrocytoma
Others x3
From non-CNS Tissues x2

Answer 3

1.) Meningioma - benign tumour of the meninges

2. ) Astrocytoma - malignant tumour of astrocytes
   - direct spread along white matter pathways and can also spread to distant parts of the CNS via the CSF
   - low grade: slow growing but difficult to remove
   - high grade: glioblastoma multiforme (GBM)
3. ) Others
   - neurofibroma: Schwann cells of peripheral or CNs
   - ependymoma: ependymal cells lining ventricles
   - neuronal tumours: extremely rare
4. ) From non-CNS Tissues
   - lymphoma
   - metastases (most common of all brain tumours)