11. Neuropathology

Question 1

What are the three routes microorganisms can gain entry to the CNS via?

Answer 1

Direct spread, blood-borne, iatrogenic.

Question 2

What is meningitis?

Answer 2

The inflammation of the leptomeninges - pia and arachnoid, with or without septicaemia.

Question 3

What are the likely causative organisms of meningitis in neonates?

Answer 3

E. coli, L. monocytogenes.

Question 4

What are the likely causative organisms of meningitis in 2-5 year olds?

Answer 4

H. influenzae type B.

Question 5

What are the likely causative organisms of meningitis in 5-30 year olds?

Answer 5

N. meningitides.

Question 6

What are the likely causative organisms of meningitis in people over 30 years old?

Answer 6

S. pneumoniae.

Question 7

What is chronic meningitis cause by?

Answer 7

M. tuberculosis.

Question 8

What is chronic meningitis?

Answer 8

Chronic clinical course with granulomatous inflammation, fibrosis of meninges, and nerve entrapment.

Question 9

What are the local complications of meningitis?

Answer 9

Death from RICP due to swelling, cerebral infarction causing neurological deficit, cerebral abscess, subdural empyema, epilepsy.

Question 10

What is encephalitis?

Answer 10

A viral infection of the parenchyma which causes neuronal cell death.

Question 11

What is the result of encephalitis considering the temporal lobe, spinal cord motor neurones, brain stem, and lymphocytic inflammatory reaction?

Answer 11

Temp - epilepsy. Spinal cord - MN signs. Brain stem - quick fatality. Lymph - swollen brain so RICP and death.

Question 12

What causes encephalitis of the: temporal lobe, spinal cord motor neurones, and brain stem?

Answer 12

Temp - herpes virus, SC - polio, brain stem - rabies.

Question 13

What is the histological presentation of cytomegalovirus?

Answer 13

Owl’s eyes.

Question 14

Which patients suffer from CMV?

Answer 14

HIV and AIDS immunocompromised patients.

Question 15

What are prions?

Answer 15

Proteins that are part of the normal constituent of synapses.

Question 16

How can prion proteins become mutated?

Answer 16

Sporadic, familial or ingested.

Question 17

What is the pathophysiology of prions disease?

Answer 17

Prion proteins aggregate and cause neuronal death so holes form in grey matter.

Question 18

What is variable Creutzfeld-Jacob disease an example of?

Answer 18

A spongiform encephalopathy.

Question 19

What is dementia?

Answer 19

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

Question 20

What are the types of dementia?

Answer 20

Alzheimers, vascular, Lewy body, and Picks disease.

Question 21

What are the features of Alzheimer’s disease?

Answer 21

Loss of cortical neurones (decreased brain weight, cortical atrophy) due to increased neuronal damage.

Question 22

What can neuronal damage be due to in Alzheimer’s disease?

Answer 22

Neurofibrillary tangles and senile plaques.

Question 23

What are neurofibrillary tangles?

Answer 23

Intracellular twisted filaments of Tau protein. Tau is hyperphosphorylated.

Question 24

What are senile plaques?

Answer 24

Foci of enlarged axons, synaptic terminals and dendrites with amyloid deposits in vessels in the centre of plaques.

Question 25

Which mutations of chromosome 21 cause early onset AD with Down's syndrome?

Answer 25

Amyloid precursor protein gene, presenilin genes 1 and 2 code for components of secretase enzymes, lead to incomplete breakdown of APP and amyloid is deposited.

Question 26

What is normal intracranial pressure?

Answer 26

0-10mmHg.

Question 27

What are the compensation mechanisms involved in maintaining normal intracranial pressure?

Answer 27

Reduced blood volume, reduced CSF volume, spatial-brain atrophy.

Question 28

What are the consequences of expanding lesions in the cranium?

Answer 28

Deformation or destruction of the brain around the lesion, displacement of midlines structures, brain shift can cause internal herniation.

Question 29

What is a subfalcine herniation?

Answer 29

On same side as mass, cingulate gyrus is pushed under the free edge of the falx cerebri.

Question 30

How can subfalcine hernias cause infarction?

Answer 30

Ischaemia of medial parts of the frontal and parietal lobe and corpus callosum due to compression of anterior cerebral artery -> infarction.

Question 31

What is a tentorial herniation?

Answer 31

Uncus/medial part of parahippocampal gyrus herniates through tentorial notch.

Question 32

How do tentorial hernias cause dilated pupils?

Answer 32

Damages oculomotor nerve on the same side.

Question 33

How are tentorial hernias frequently fatal?

Answer 33

Secondary haemorrhage into brainstem -> duret haemorrhage.

Question 34

How can tentoral hernias cause infarction?

Answer 34

Occludes blood flow in posterior cerebral and superior cerebellar arteries.

Question 35

What is a tonsilar herniation?

Answer 35

Cerebellar tonsils are pushed into foramen magnum, compressing the brainstem.

Question 36

What is a benign tumour of the brain?

Answer 36

Meningioma.

Question 37

What is a malignant brain tumour?

Answer 37

Astrocytoma.

Question 38

Name a tumour of the brain from non-CNS tissues.

Answer 38

Lymphoma, metastasis.

Question 39

What is a stroke?

Answer 39

Sudden event producing a disturbance of CNS function due to vascular disease.

Question 40

What are the two categories of stroke?

Answer 40

Cerebral infarction (85%) and cerebral haemorrhage (15%).

Question 41

What is the pathogenesis of strokes?

Answer 41

Embolism or thrombosis.

Question 42

What are the types of cerebral infarct?

Answer 42

Regional and lacuna.

Question 43

What are the two common haemorrhages in cerebral haemorrhage strokes?

Answer 43

Intracerebral and subarachnoid.

Question 44

What is intracerebral haemorrhage associated with?

Answer 44

Hypertensive vessel damage, Charcot-Bouchard aneurysms, deposition of amyloid around cerebral vessels in the elderly.

Question 45

What causes subarachnoid haemorrhages?

Answer 45

Rupture of berry aneurysms.

Question 46

Where are berry aneurysms found?

Answer 46

Circle of Willis.

Question 47

What is the presentation of subarachoid haemorrhages?

Answer 47

Sudden severe headache (thunderclap), sentinel headache (build up from small bleeds), loss of consciousness. Instantly fatal.