Extradural haemorrhage

Question 1

indications for surgery for extradural haemorrhage ?

Answer 1

extradural haematoma volume > 30 cm3

midline shift > 5 mm

haematoma thickness > 15mm

neurological deficit
GCS < 8

Question 2

features of extradural haemorrhage on CT ?

Answer 2

hyperdense lentiform (biconvex) extra-axial collection

Question 3

describe how a fixed dilated pupil occurs in an extradural haemorrhage.

Answer 3

as haematoma expands, the uncus of the temporal lobe herniates around the tentorium cerebelli
this compresses the parasympathetic fibres of the 3rd CN causing a fixed and dilated pupil

Question 4

damage to what vessel is responsible for an extradural haemorrhage ?

Answer 4

middle meningeal artery

the thin pterion overlies the MMA and is therefore vulnerable to injury

Question 5

what bones form the pterion?

Answer 5

frontal, temporal, parietal and sphenoid

Question 6

what factors determine prognosis of extradural haemorrhage ?

Answer 6

age 
GCS 
pupillary abnormality 
associated intracranial lesions 
time between neurological deterioration, decreasing GCS and surgery