Collection of blood between the skull and the dura mater

Aetiology

• Almost always trauma-related, specifically severe head trauma that results in a tear of the middle meningeal artery

Clinical features

• A characteristic picture is that of a head injury with a brief duration of unconsciousness, followed by improvement (lucid interval)
• The patient then becomes stuporose; there is an ipsilateral dilated pupil and contralateral hemiparesis, with rapid transtentorial coning
• Bilateral fixed, dilated pupils, tetraplegia and respiratory arrest follow

Investigations

• Urgent CT brain: described as a lens shaped lesion (biconvex)
  • Limited to the skull sutures where the dura adheres to the skull

Management

• Depends on the severity of the symptoms and the extent of the mass effect on the brain
• Can range from conservative management with close observation in mild cases to urgent neurosurgical evacuation of the haematoma in severe cases