8. Intro To Neuropathology

Question 1

How do microorganisms gain entry to CNS?

Answer 1

Direct spread - e.g. middle ear infection, base of skull fracture
Blood-borne - e.g. sepsis, infective endocarditis
Iatrogenic - e.g. V-P shunt, surgery, lumbar puncture

Question 2

What are the 2 main bacteria which cause neonatal meningitis?

Answer 2

E.coli

L.monocytogenes

Question 3

What is the main causative organism of meningitis in 2-5years?

Answer 3

H.influenzae ty B

Question 4

What is the most common causative organism of meningitis in 5-30years?

Answer 4

N.meningitides

Question 5

What is the main causative organism of meningitis over 30 years?

Answer 5

S.pneumoniae

Question 6

What is the causative organism of chronic meningitis?

Answer 6

M.tuberculosis

Question 7

What are the local complications of meningitis?

Answer 7

Death
Cerebral infarction - neurological defect
Cerebral abscess
Subdural empyema
Epilepsy

Question 8

What happens in prion disease?

Answer 8

PrP aggregates - causes neuronal death and holes in grey matter

Question 9

What is the definition of dementia?

Answer 9

Acquired global impairment of intellect, reason and personality without impairment of consciousness

Question 10

What happens pathologically in Alzheimer’s disease?

Answer 10

Loss of cortical neurones - decreased brain weight, cortical atrophy
Due to increased neuronal damage - neurofibrillary tangles, senile plaques

Question 11

What are neurofibrillary tangles?

Answer 11

Intracellular twisted filaments of Tau protein
Tau normally binds and stabilised microtubules
Tau becomes hyperphosphorylated in AD

Question 12

What are senile plaques?

Answer 12

Foci of enlarged axons, synaptic terminals and dendrites

Amyloid deposition in vessels in centre of plaque

Question 13

What are the compensation mechanisms that maintain normal ICP?

Answer 13

Reduced blood volume
Reduced CSF volum
Spatial - brain atrophy

Question 14

What can increase ICP?

Answer 14

Tumour, haemorrhage, oedema

Question 15

What happens in a subfalcine herniate on?

Answer 15

Same side as mass
Cingulate gyrus pushed under the free edge of the flax cerebri
Ischaemia of medial parts of the frontal and parietal lobe and corpus callosum due to compression of anterior cerebral artery - leads to infarction

Question 16

What is a tentorial herniation?

Answer 16

Uncus/medial part of parahippocampal gyrus through the tentorial notch
Damage to oculomotor nerve on the same side
Occlusion of blood flow in posterior cerebral and superior cerebellar arteries
Frequently fatal because of secondary haemorrhage into brainstem

Question 17

What is a tonsillar herniation?

Answer 17

Cerebellar tonsils pushed into foramen magnum compressing the brainstem

Question 18

Name a benign primary CNS tumour

Answer 18

Meningioma

Question 19

Name a malignant primary brain tumour

Answer 19

Astrocytoma - spread along nerve tracts and through subarachnoid space often presents with a spinal secondary

Question 20

What are the 2 broad categories of stroke?

Answer 20

Cerebral infarction (most common)
Cerebral haemorrhage

Question 21

What are the signs/symptoms of subarachnoid haemorrhage?

Answer 21

Sudden severe headache (thunderclap)
Sentinel headache
Loss of consciousness
Often instantly fatal