Pathophysiology

Traumatic laceration of the middle meningeal artery which runs between the bone and the dura, often due a fracture of the temporal or parietal bone (75%). Can also be caused by tears in a dural venous sinus, or middle meningeal vein.

Classic presenting complaint

• Young person, head trauma to the temple area
• Post-traumatic LOC (brief)
• Lucid interval
• Deteriorating consciousness, vomiting, headache, seizures.

Lucid interval can last hours-days.

On examination

As ICP increases:

• reducing consciousness
• hemiparesis, brisk reflexes and upgoing plantars contralateral to injury*
• dilated pupil ipsilateral to injury indicates brainstem compression
• respiratory arrest

Hypertension + bradycardia are late findings

*Kernohan’s phenomenon: brainstem displacement away from haematoma can cause compression of the contralateral cerebral peduncle, producing hemiparesis and UMN signs ipsilateral to the bleed – a false localising sign

Clinical approach & differential

Differential:

• Subdural haemorrhage
• Stroke
• Concussion

Urgent non-contrast CT required

LP contraindicated due to risk of herniation

Classic findings

High density biconvex (lenticular) opacity adjacent to skull, usually limited by skull sutures. Mass effect usually evident.

Rarely can appear crescent shaped, similar to subarachnoid haemorrhage.

Treatments

Mannitol

Refer to neurosurgeons for clot evacuation and ligation of artery.