Head Injury

Question 1

Extradural haematoma

Answer 1

• Bleeding into the space between the dura mater and the skull
• Often results from acceleration-deceleration trauma or a blow to the side of the head
• Majority occur in temporal region where skull fractures cause rupture of the middle meningeal artery in the tempero-parietal region
• Features include:
  
  • Raised ICP
  • Triphasic presentation (LOC > lucid interval (minutes to hours) > headache, progressive obtundation and hemiparesis
  • Can lead to blown pupil secondary to uncal herniation
  • Blown pupil will be ipsilateral and hemiparesis will be contralateral
• CT findings - Convex, lens-shaped hyperdensity that may cross the midline
• Management - neurosurgical emergency, drainage is always necessary
• Better prognosis with earlier treatment

Question 2

Subdural haematoma

Answer 2

• Bleeding into the outermost meningeal layer
• Most commonly around the frontal and parietal lobes
• May be acute or chronic
• Risk factors include old age and alcoholism
• Head trauma causes rupture of bridging veins
• May be focal signs but clinical signs are usually non-localising and include headache and altered mental status
• Can be weeks after initial fall before patients present
• CT findings - crescent-shaped hyperdensity that does not cross the midline, midline shift and compression of lateral ventricle may be present
• Neurosurgical emergency - drainage almost always necessary
• High mortality

Question 3

Criteria for immediate CT imaging of the head in children

Answer 3

• Loss of consciousness lasting more than 5 minutes (witnessed)
• Amnesia (antegrade or retrograde) lasting more than 5 minutes
• Abnormal drowsiness
• Three or more discrete episodes of vomiting
• Clinical suspicion of non-accidental injury
• Post-traumatic seizure but no history of epilepsy
• GCS less than 14, or for a baby under 1 year GCS (paediatric) less than 15, on assessment in the emergency department
• Suspicion of open or depressed skull injury or tense fontanelle
• Any sign of basal skull fracture (haemotympanum, panda’ eyes, cerebrospinal fluid leakage from the ear or nose, Battle’s sign)
• Focal neurological deficit
• If under 1 year, presence of bruise, swelling or laceration of more than 5 cm on the head
• Dangerous mechanism of injury (high-speed road traffic accident either as pedestrian, cyclist or vehicle occupant, fall from a height of greater than 3 m, high-speed injury from a projectile or an object)

Question 4

Pupillary findings in head injury

Answer 4