Epidural Hematoma

What happens in an epidural hematoma

The skull is lined on the inside by the dura. Arteries run in grooves on the inner surface of the skull, and the middle meningeal artery lies just under the thin temporal bone at the side of the head. A blow there can fracture the bone and tear the artery. Because it is an artery, blood under high pressure peels the dura away from the skull and the clot expands quickly, pressing on the brain.

As pressure rises inside the skull, the brain can be pushed out of place (brain herniation), compressing the brainstem, which controls breathing and consciousness. This can be fatal within hours.

About 10 percent of epidural hematomas come from torn veins or venous sinuses, which bleed more slowly.

Causes and risk factors

• Head injury: falls, car and motorcycle crashes, assaults, and sports such as baseball, cricket, skiing and horse riding
• Skull fracture: present in most adult cases
• Age: most common in teenagers and young adults. It is less common in older adults because the dura is more firmly attached to the skull
• Children: can develop epidural hematomas from falls, sometimes without a fracture because their skulls are flexible

Symptoms

The lucid interval

About 1 in 3 to 1 in 2 people show the classic pattern:

1. a brief loss of consciousness at impact
2. a period of being awake and talking normally, lasting minutes to hours
3. rapid deterioration as the clot grows

Others are unconscious from the start or never lose consciousness, so the absence of a lucid interval does not rule it out.

Warning signs

• severe and worsening headache
• repeated vomiting
• increasing drowsiness and confusion
• dizziness
• a dilated pupil, usually on the same side as the clot
• weakness of the arm and leg on the opposite side
• seizures
• slow heart rate, high blood pressure and irregular breathing late in the course

In infants, signs include irritability, vomiting, poor feeding, a bulging soft spot and pale skin from blood loss.

Epidural vs subdural hematoma

Diagnosis

A non-contrast CT scan of the head is the key test. It shows a characteristic lens-shaped clot, any skull fracture and shift of the brain. Doctors also:

• assess consciousness with the Glasgow Coma Scale
• check pupils, limb strength and vital signs repeatedly
• check clotting and blood counts, especially in people on anticoagulants

Guidelines advise CT scans after head injury for anyone with risk factors such as loss of consciousness, vomiting, a dangerous mechanism, confusion, suspected skull fracture, age over 65 or blood thinner use.

Treatment

Surgery

Most epidural hematomas need emergency craniotomy: a neurosurgeon opens a section of skull, removes the clot, stops the bleeding vessel and replaces the bone. Surgery is usually recommended for clots over 30 cubic centimeters, or for anyone with a reduced level of consciousness or a dilated pupil. Speed matters, because outcomes depend heavily on how quickly pressure is relieved.

Observation

Small epidural hematomas in alert people without neurological signs may be monitored in hospital with repeated examinations and CT scans, as long as a neurosurgeon is available.

Supportive care

• reversing blood thinners
• controlling pressure inside the skull
• anti-seizure medicines when needed
• intensive care monitoring

Recovery and outlook

With prompt surgery, most people with an isolated epidural hematoma make a good recovery, because the brain itself is often not badly injured. Outcome is worse in people who were deeply unconscious before surgery, had both pupils dilated, had other brain injuries, or experienced delays in treatment.

Recovery may include headaches, tiredness, concentration problems and mood changes, similar to other forms of traumatic brain injury. Rehabilitation helps. Return to driving and contact sports depends on medical advice.

Prevention

• wear helmets for cycling, motorcycling, skiing, skating, horse riding and contact sports
• wear seatbelts and use correct child car seats
• make homes safer for older adults and young children to reduce falls
• seek immediate medical care for anyone who seems to recover after being knocked out

Frequently asked questions

What is the lucid interval in an epidural hematoma?

It is a period after a head injury when the person wakes up and seems normal, lasting minutes to hours, before rapidly becoming drowsy and confused as the clot expands. It occurs in a significant proportion of cases and is why anyone knocked out should be assessed even if they feel fine.

How fast does an epidural hematoma develop?

Usually over minutes to a few hours, because the bleeding is typically from an artery under high pressure. Slower venous bleeds can take longer. This is why close monitoring in the first hours after a significant head injury is important.

Can you survive an epidural hematoma?

Yes. With rapid diagnosis and surgery, most people survive and recover well, because the underlying brain is often not badly damaged. Delays in treatment, deep coma before surgery and other brain injuries worsen the outlook.

What is the difference between an epidural and subdural hematoma?

An epidural hematoma lies between the skull and the dura and usually comes from a torn artery, often in younger people with a skull fracture. A subdural hematoma lies beneath the dura, usually from torn veins, and is more common in older adults and people on blood thinners.

What are the signs of bleeding on the brain after a head injury?

Worsening headache, repeated vomiting, increasing drowsiness, confusion, slurred speech, weakness on one side, a seizure or unequal pupils. Call 911 or your local emergency number immediately if any of these develop after a head injury.