Acute Subdural Hematoma

An acute subdural hematoma is a blood clot which develops between the brain and the dura mater (the brains outer covering). This is caused by a head injury which tears the veins on the brains surface.

Symptoms of an Acute Subdural Hematoma

  • Increasingly severe headache.
  • Dilated pupil on the injured side.
  • Slow pulse.
  • High blood pressure.
  • Vomiting.
  • Unconsciousness.


The cause of an acute subdural hematoma is an impact to the head. This may be from a fall, road traffic accident or sporting injury, such as being hit by a hard ball.

ASH's are among the most dangerous of all head injuries. They account for 10-20% of all traumatic brain injuries and around 30% of all fatal head injuries.


  • Seek medical attention immediately.
  • Once at the hospital, a CT scan may be undertaken to determine the cause and extent of the injury.
  • Surgery is usually required to remove the blood clot and stop the bleeding.
  • Small hematoma's may not require surgery.
  • Following surgery, close observation is required.
  • A significant number of deaths from ASH's occur in the days after surgery due to pressure on the brain or underlying brain injury.