8.3.2 CNS Tumours

Question 1

What are the two types of CNS tumours?

Answer 1

Primary
- Gliomas
- Parenchymal
- Meningeal
- Neuronal
- Poorly differentiated- medulloblastoma

Secondary
- Metastatic- paraneoplastic

Question 2

What are some examples of gliomas?

Answer 2

Think of what glial cells actually are

-Astrocytic tumours
-Oligodendrogliomas
-Ependyomas
-Colloid cysts of 3rd ventricle

Question 3

What are the types of parenchymals tumours?

Answer 3

CNS lymphomas
Germ cell

Question 4

What are meningeal tumours called?

Answer 4

Meningiomas

Question 5

What are the different types of neuronal tumours?

Answer 5

Ganglion cell tumours
Neuroblastomas

Question 6

What are gliomas?

Answer 6

Malignant tumours
Graded 1-5

Astrocytic tumours
- Most common is astrocytic, low to high grade, 80%
- Glioblastoma multiforme- grade 4-5

Oligodendrogliomas
- 20% gliomas, grade 2-4

Ependymoma
- Ventricular system
- Often disseminated into CSF

Question 7

What are lymphomas?

Answer 7

Diffuse, large B cell lymphomas

Associated with EBV

Question 8

What are germ cell tumours?

Answer 8

Midline tumours, pineal and suprasellar

e.g. germinoma

Question 9

Where do medulloblastomas occur?

Answer 9

Cerebellum

20% children
Radiosensitive

Question 10

What are meningiomas?

Answer 10

Benign
Derived from arachnoid meningothelial cells

Can compress structures

Question 11

How can infection enter into the CNS?

Answer 11

Direct- Air sinuses, skull fractures

Haematogenous- Arterial blood, venous sinuses

Iatrogenic- LP, surgery

Peripheral nerve- HZV, viruses

Question 12

What is affected by infections entering the CNS?

Answer 12

Meninges
Aggregates of acute inflammation
Brain parenchyma

Question 13

What is meningitis?

Answer 13

Inflammation of leptomeninges

Question 14

What are the different types of meningitis?

Answer 14

Acute pyogenic- Bacterial
Aseptic- Viral, immunocompromised
Chronic- myco tuberculosis- fungi
Carcinomatosis- spread of cancer

May be due to septicaemia

Question 15

How does meningitis present?

Answer 15

Headache
Photophobia
Irritability
Altered consciousness
Stiff neck- meningeal irritation
Focal neurological impairment

Question 16

What investigations are done for meningitis?

Answer 16

CT scan
Lumbar puncture

Question 17

What are the complications of meningitis?

Answer 17

Cerebral oedema
Cerebral infarction
Cerebral abscess / empyema
Epilepsy
Meningoencephalitis
Septicaemia

Question 18

What infective organisms cause meningitis at each age?

Answer 18

Infants
- Escherichia Coli
- Group B streptococci

Young adults
- Neisseria meningitidis

Older adults
- Streptococcus pneumoniae
- Listeria monocytogenes

Chronic meningitis
- Mycobacterium tuberculosis

Question 19

What organisms causes a cerebral abscess?

Answer 19

Streptococci or staphylococci

Question 20

What organisms cause empyema?

Answer 20

Polymicrobial (staphylococci, anaerobic gram -ve)

Question 21

What is encephalitis?

Answer 21

Infection of the brain parencyma

Question 22

What are some features of encephalitis?

Answer 22

Usually viral
Neurone death by viruses
Prominent lymphocytes

Question 23

Give some examples of viruses causing encephalitis and what lobe they affect

Answer 23

Herpes Zoster- Temporal lobe

Polio
Spinal cord motor neurones

Rabies
Brainstem

Question 24

What viruses can cause encephalitic syndromes?

Answer 24

Herpes simplex virus, HSV-1 and HSV-2
CMV
HIV

Question 25

What are prion diseases?

Answer 25

Abnormal cellular protein accumulations which lead to cell injury in and out of the cell:
- Neurone cell death
- Synapse loss
- Microvacuolations
- Lack of inflammation

Question 26

Why are prion diseases infective?

Answer 26

Causes abnormal protein aggregates to accumulate in local cells

Question 27

What can cause prion diseases?

Answer 27

Sporadic
Familial
Iatrogenic
Ingested (think of House episode with the water)

Question 28

What are the different types of prion disease?

Answer 28

• Creutzfeldt- Jakob Disease and variant CJD
• Scrapies (sheep)
• Bovine spongiform encephalopathy (Mad Cow disease)

Question 29

What happens to proteins in prion disease?

Answer 29

Normal brain proteins are rich in alpha helices

Initiation
Prion disease ingested. inoculated or sporadic, this causes conformational change to beta pleated sheet

Propagation
Abnormal proteins cause surrounding proteins to undergo conformational change from alpha helices to beta pleated sheets

Aggregation
Abnormal proteins aggregate forming amyloid plaques and spongiform brain

Question 30

What are the features of Creutzfeld Jakob Disease?

Answer 30

• Normally sporadic (familial form)
• 1 per million very rare
• Rapidly progressive dementing illness
• Subtle changes in memory
• Cerebellar ataxia
• Global dementia
• Definitive diagnosis- post mortem
• Often brain looks normal, may have atrophy or ventricular enlargement

Question 31

What are the features of variant Creutzfeld Jakob Disease?

Answer 31

• Affects young adults
• Slower progression
• Starts with behavioural issues
• Exposure due to cattle- e.g. meat and blood transfusions
• Prolonged incubation, 15 years

Question 32

What causes neurodegenerative diseases?

Answer 32

Loss of neurones
Accumulation of protein aggregates

Question 33

What happens in neurodegenerative diseases affecting the hippocampus and cerebral cortices?

Answer 33

Changes in:
- Cognitive
- Memory
- Behaviour
- Language

Question 34

What happens in neurodegenerative diseases affecting the Basal ganglia?

Answer 34

Movement disorders, hypo/hyperkinetic

Question 35

What happens in neurodegenerative diseases affecting the cerebellum?

Answer 35

Ataxias, motor neurones can also be hit

Question 36

Who is affected by Alzheimer’s disease?

Answer 36

3% of 65-74 year olds, increases with age

Sporadic 90% of the time

Can be familial which causes earlier onset, 5-10%

Question 37

What happens in Alzheimer’s?

Answer 37

Alpha beta plaques and neurofibrillary tangles (tau) form

This accumulation causes neuronal damage, this leads to loss of neurones

Loss of neurones causes cortical atrophy and shrunken brain

Affects frontal, temporal and parietal lobes

Question 38

How do plaques and tangles form?

Answer 38

Amyloidogenic pathway
- Transmembrane protein on chromosome 21 cleaved to alpha beta monomer by beta and and gamma secretase
- Alpha beta monomers clump together forming oligomers, these then aggregate forming fibrils which then form tangles
- Tau aggregates are formed by alpha beta oligomers becoming hyperphosphorylated, this causes neuronal damage

Non-amyloidogenic pathway
- Alpha and gamma secretase cleave

Question 39

Why are people with Down syndrome at increased risk of Alzheimer’s disease?

Answer 39

Protein which causes Alzheimer’s is found on chromosome 21

In Down syndrome, there are 3 chromosome 21s, therefore more likely to have plaque and tangle formation

Question 40

What are the signs and symptoms of Alzheimer’s?

Answer 40

Impaired memory
Impaired intellectual function
Altered mood and behaviour
Disorientated

Question 41

What causes Parkinson’s disease?

Answer 41

Loss of dopaminergic neurones in the substantia nigra pars compacta

Lewy body involvement (alpha synuclein)

Question 42

What are the symptoms of Parkinson’s?

Answer 42

Sometimes TRAPPED D*ck Means Femoral Hernia

Shuffling gait

Tremor
Rigidity
Akinesia
Pill-rolling tremor
Postural instability
Expressive aphasia
Dementia

Depression
Micrographia
Facial weakness
Hypokinesia

Question 43

What causes Huntington’s?

Answer 43

Autosomal dominant condition

Increased CAG repeats

Mutant protein broken down to aggregates which causes damage

Loss of inhibitory neuronal projection to corpus striatum

Question 44

What are the signs of Huntington’s?

Answer 44

CDCD

Chorea
Distonia
Co-ordination loss
Decline in cognition