Epidural Hemorrhage (EDH)

What happens in an epidural hemorrhage

The brain is wrapped in three layers (meninges). The outermost, the dura mater, is firmly stuck to the inner surface of the skull. Running in grooves on the inside of the skull, between bone and dura, are arteries, most importantly the middle meningeal artery beneath the thin temple bone.

When a blow fractures the skull, the bone edge can tear this artery. Arterial blood under pressure peels the dura away from the bone and collects in a lens-shaped (biconvex) pocket. Because the dura is attached tightly at the skull's suture lines, the clot usually cannot spread past them, so it bulges inward and compresses the brain.

As the clot grows, pressure inside the skull rises. The brain can be pushed across or downward (brain herniation), compressing the brainstem, which controls breathing and consciousness. This can happen within hours, which is why speed matters.

About 10 to 15 percent of epidural hemorrhages come from torn veins or venous sinuses rather than an artery. These grow more slowly and may not show symptoms for a day or more.

Epidural vs subdural vs subarachnoid bleeding

Causes and risk factors

• Falls, including from bicycles, ladders and stairs
• Road traffic crashes
• Assaults and blows from objects
• Sports injuries, especially those without head protection, such as being struck by a baseball or golf ball

Epidural hemorrhage is most common in teenagers and young adults, and in men. In older adults the dura is more firmly stuck to the skull, so subdural bleeding is more common after falls. In young children, whose skulls are more flexible, an EDH can occur without a visible fracture.

Most cases (around 70 to 90 percent) have an associated skull fracture, usually of the temporal bone at the side of the head.

Symptoms

The classic story is the lucid interval: the person is knocked out briefly, wakes up and seems fine, then minutes to hours later becomes drowsy and deteriorates. Only around 1 in 5 to 1 in 3 people show this textbook pattern. Others are unconscious from the start, and some never lose consciousness at first. The detailed clinical picture is described on our epidural hematoma page.

Signs of a growing bleed include:

• Severe, worsening headache
• Repeated vomiting
• Increasing drowsiness and confusion
• One pupil becoming large and not reacting to light, usually on the side of the clot
• Weakness of the arm and leg on the opposite side of the body
• Seizures
• Slow pulse, high blood pressure and irregular breathing, late signs of dangerous pressure on the brainstem

How it is diagnosed

In the emergency department, doctors check breathing and circulation first, then assess level of consciousness with the Glasgow Coma Scale (scored from 3 to 15), pupil responses and limb strength.

A non-contrast CT scan of the head is the key test. It is fast, widely available and shows fresh blood as a bright, lens-shaped collection pressing on the brain, along with any fracture and midline shift. Guidelines such as NICE's recommend CT within an hour for anyone with red flags after a head injury, including reduced consciousness, vomiting more than once, a seizure, signs of skull fracture, or any loss of consciousness or memory in someone taking blood thinners.

Blood tests check clotting, blood count and blood group in case surgery and transfusion are needed. Other injuries, especially to the neck, are looked for at the same time.

Treatment

Emergency surgery

Most symptomatic epidural hemorrhages are treated with a craniotomy: the neurosurgeon removes a flap of skull bone, washes out the clot, stops the bleeding vessel and replaces the bone. Surgical guidelines recommend evacuation for a clot larger than 30 ml regardless of symptoms, and for smaller clots that cause significant shift or neurological decline. In remote settings, an emergency burr hole may be used to release pressure while the patient is transferred.

Close observation

A small clot (under about 30 ml, less than 15 mm thick, with little shift) in an alert patient may be managed without surgery. The patient stays in hospital with frequent neurological checks and repeat CT scans, because some clots enlarge in the first 6 to 8 hours.

Supportive care

• Reversing blood thinners and correcting clotting problems
• Controlling blood pressure, oxygen and carbon dioxide levels
• Seizure-prevention medicine for a short period in some patients
• Treating other injuries

Spinal epidural hemorrhage

Bleeding can also collect in the epidural space of the spine, compressing the spinal cord or nerve roots. It is rare and is usually linked to blood thinners, bleeding disorders, spinal injury or procedures such as epidural injections and lumbar punctures, though it can occur without an obvious cause. Symptoms are sudden, severe back or neck pain followed within hours by weakness, numbness and bladder or bowel problems. Diagnosis is by urgent MRI, and treatment is usually emergency surgery to remove the clot.

Complications

• Brain herniation and death if not treated in time
• Lasting effects of traumatic brain injury such as memory, concentration or mood changes
• Post-traumatic epilepsy
• Weakness or speech problems if brain tissue was damaged
• Injuries associated with the original trauma

Outlook

Epidural hemorrhage has one of the best outlooks of all serious head bleeds when it is treated promptly, because the brain underneath is often not badly injured. Death rates in modern series are around 5 to 10 percent and are much higher in people who arrive in a deep coma with fixed, dilated pupils. People who are awake before surgery usually make a good or full recovery. The level of consciousness before the operation is the strongest predictor of outcome.

After discharge, recovery may take weeks to months. Many people benefit from follow-up with a neurologist, brain injury rehabilitation, and a gradual return to work, school, driving and sport as advised by their team.

Preventing head injuries

• Wear a properly fitted helmet for cycling, motorcycling, skiing, skating and contact sports.
• Use seat belts and correctly fitted child car seats.
• Make homes safer for children and older adults: stair gates, window guards, good lighting and removing trip hazards.
• Do not let anyone return to sport the same day after a head injury.

Frequently asked questions

What is an EDH hemorrhage?

EDH stands for epidural hematoma or epidural hemorrhage. It is bleeding between the skull and the dura, the brain's outer covering, usually from an artery torn by a skull fracture. It can press on the brain within hours and needs emergency CT scanning and often surgery.

Is an epidural hemorrhage the same as an epidural hematoma?

Practically, yes. Hemorrhage means bleeding and hematoma means the collection of clotted blood that results. Doctors use both terms, along with extradural hemorrhage, for the same injury.

Can you survive an epidural hemorrhage?

Yes. Most people survive, especially when the bleed is found and drained before they lose consciousness. Outcomes are worst when treatment is delayed until the person is in a deep coma. That is why any worsening after a head injury needs an emergency CT scan.

What is the lucid interval?

It is a period after a head injury when the person wakes up and seems normal, before deteriorating as the clot grows. It can last minutes to hours. It is classically linked to epidural hemorrhage but does not happen in every case, and other bleeds can cause it too.

How long after a head injury can an epidural hemorrhage develop?

Most arterial epidural bleeds show symptoms within a few hours. Venous bleeds can develop more slowly, over a day or more. Anyone with a significant head injury should be watched closely for at least 24 hours, and anyone who gets worse should be seen urgently.

Do all epidural hemorrhages need surgery?

No. Small clots in people who are alert and stable can be watched in hospital with repeat CT scans, and the body gradually reabsorbs the blood over weeks. Larger clots, or any clot causing symptoms or brain shift, are removed surgically.