Space Occupying Lesions and Herniations

Question 1

What are the symptoms of a space occupying lesion?

Answer 1

raised ICP 
- headache worse on waking, lying down, bending forward, coughing 
- vomiting 
- papilloedema 
- reduced GCS 
seizures 
evolving focal neurology 
subtle personality changes

Question 2

List 4 causes of SOL.

Answer 2

tumours (primary or mets)
abscess
haematoma
localised brain swelling e.g. oedema around cerebral infarct

Question 3

How are SOL diagnosed?

Answer 3

CT/MRI

avoid LP before imaging

Question 4

Why is LP avoided before imaging?

Answer 4

risks coning - cerebellar tonsils herniate through foramen magnus

Question 5

Why does herniation occur in increased ICP?

Answer 5

herniation of brain tissue through routes of weakest resistance

Question 6

What is a subfalcine herniation?

Answer 6

asymmetric expansion of cerebral hemisphere displaces cingulate gyrus under falx cerebri

Question 7

What gets compressed in a subfalcine herniation?

Answer 7

ACA (weakness and sensory loss in leg)

Question 8

What is a tentorial herniation?

Answer 8

medial aspect of temporal lobe herniates over tentorium cerebelli

Question 9

What gets compressed in a tentorial herniation?

Answer 9

CN III and its parasympathetic fibres –> pupillary dilation and impaired ocular movements

Question 10

What is a tonsillar herniation?

Answer 10

displacement of cerebellar tonsils through foramen magnum

Question 11

What is compressed in a tonsillar herniation?

Answer 11

brain stem, compromising respiratory centres in medullar oblongata