Extradural haemorrhage

Question 1

Define extradural haemorrhage

Answer 1

collection of blood that forms between the inner surface of the skull and periosteal outer layer of the dura

Question 2

Epidemiology of extradural haemorrhage

Answer 2

• Young patients who have sustained head trauma
• 10-20% of all patients with head injuries
• 17% of previously conscious patients who deteriorate into a coma
• 3.5% mortality
• 4x more common in males
• Half as common as subdural haemorrhages

Question 3

Investigations of extradural haemorrhage

Answer 3

• CT
o Biconvex/lentiform
o Most frequently beneath the squamous part of the temporal bone
o Hyperdense, somewhat heterogeneous
o Secondary features of mass effect
 Midline shift, subfalcine/uncal herniation
o Swirl sign = active bleeding
o Skull fracture
• MRI
o Hypointense line on T1 and T2 sequences – distinguishes it from a subdural haematoma
• Angiography
o To evaluate non-traumatic cause (e.g. arteriovenous malformations)

Question 4

Presenting symptoms of extradural haemorrhage

Answer 4

• Ongoing and severe headache
• Vomiting
• Seizures
• Gradual loss of consciousness
• Classic lucid interval (20-50%)
• Reduced GCS
• Loss of visual field (opposite side)

Question 5

Aetiology of extradural haemorrhage

Answer 5

• Typically caused by trauma (blunt impact from assault/fall)
• New-borns – dystocia, forceps delivery and excessive skull moulding through the birth canal

Question 6

Signs of haemorrhage on physical examination

Answer 6

•	External evidence of head injuries
o	Scalp lacerations
o	Contusions
o	Cephalhematoma
•	Classic lucid interval (20-50%)
•	Pronator drift
o	Hold both arms outstretched with palms facing upward
o	Indicates subtle but significant mass effect
•	3rd nerve palsy (same side)
o	Down and out
o	Fixed and dilated pupil
•	Weakness of extremities (opposite side)
•	Respiratory arrest