BRAIN TUMOURS

Question 0

What is an acoustic neuroma? What Sx? What Ix?

Answer 0

Doubly misnamed
Arises from vestibular nerve and is a schwannoma (not neuroma).

S+S

• incidental
• unilateral hearing loss
• vertigo
• eventually raised ICP Sx

MRI
- densely enhancing lesion

Question 1

How can brain tumours be classified and what are the types?

Answer 1

Primary intra-axial

• gliomas
• astrocytomas
• oligodendriomas
• ganglioma

Primary extra-axial

• meningioma (MC primary brain tumour)
• acoustic neuroma (vestibular schwannoma)
• pituitary adenine

SECONDARY ARE FROM METASTASES (3X MC than PRIMARY)

Question 2

What is a meningioma? How are they classified? Rx?

Answer 2

Classified as benign, atypical or malignant.

Usually arise from dura mater as NEOPLASTIC meningioepithelial cells.

MRI
- densely enhancing extra-axial tumour, partially calcified.

Rx

• if small -> conservative watch/wait
• if large/symptomatic -> surgical resection +/- radio

Question 3

What are the grades of astrocytomas?

Answer 3

GRADE
I - pilocystic astrocytomas (MC children) 
II - diffuse astrocytoma (young adults) 
III - anaplastic
IV - glioblastoma

Question 4

Management of SOL?

Answer 4

Non-surgical

• if oedema -> dexamethasone
• seizure -> anti-epileptics e.g. Valproate/levitiracetam (not phenytoin or carbamazepine dt hepatic enzyme induction)
• DVT prophylaxis

Surg
- complete/ partial excision depending on location

RADIOTHERAPY - external beam radiation best for both primary and metastatic
CHEMOTHERAPY - limited

Question 5

Complications of radiotherapy?

Answer 5

External beam radiation can cause

• ACUTE: cerebral toxicity (disruption of BBB -> oedema, raised ICP)
• EARLY DELAYED: focal demyelination -> neurological deficit
• LATE DELAYED: dementia, focal necrosis (radionecrosis)