EPIDURAL OR EXTRADURAL HEMATOMA

(HAEMATOMA)

Epidural or extradural hematoma (haematoma) is a

type of traumatic brain injury (TBI) in which a buildup of

blood occurs between the dura mater (the tough outer

membrane of the central nervous system) and the skull.

Often due to

trauma, the condition is potentially deadly because the

buildup of blood may increase pressure in the intracranial

space, compress delicate brain tissue, and cause brain

shift.

The condition is present in one to three percent of head

injuries. Between 15 and 20% of epidural hematomas are

fatal.

The dura mater also covers the spine, so epidural bleeds

may also occur in the spinal column.

Signs and symptoms

Epidural bleeds, like subdural and subarachnoid

hemorrhages, are extra-axial bleeds, occurring outside of

the brain tissue, while intra-axial hemorrhages, including

intraparenchymal and intraventricular hemorrhages, occur

within it.

(VIDEO BELOW)

Hematoma Epidural (Epidural Hematoma).mp4

Epidural hematomas may present with a lucid period

immediately following the trauma and a delay before

symptoms become evident. After the epidural hematoma

begins collecting, it starts to compress intracranial

structures which may impinge on the CN III. This can be

seen in the physical exam as a fixed and dilated pupil on

the side of the injury. The eye will be positioned down and

out, due to unopposed CN IV and CN VI innervation.

Other manifestations will include weakness of the

extremities on the opposite side as the lesion (except in

rare cases), due to compression of the crossed pyramid

pathways, and a loss of visual field opposite to the side of

the lesion, due to compression of the posterior cerebral

artery on the side of the lesion.

The most feared event that takes place is the transtentorial,

or uncal herniation which results in respiratory arrest since

the medullary structures are compromised. The trigeminal

nerve (CN V) may be involved late in the process as the

pons becomes compressed, but this is not a significant

clinical presentation, since by that time the patient may

already be dead.

In the case of epidural hematoma in

the posterior cranial fossa, the

herniation is tonsillar and causes the

Cushing's triad: hypertension,

bradycardia, and irregular respiration.

Epidural bleeding is rapid because it is

usually from arteries, which are high

pressure. Epidural bleeds from arteries

can grow until they reach their peak

size at six to eight hours post injury,

spilling from 25 to 75 cubic

centimeters of blood into the

intracranial space.

As the hematoma expands, it strips

the dura from the inside of the skull,

causing an intense headache. Epidural

bleeds can become large and raise

intracranial pressure, causing the brain

to shift, lose blood supply, or be

crushed against the skull. Larger

hematomas cause more damage.

Epidural bleeds can quickly expand

and compress the brain stem, causing

unconsciousness, abnormal posturing,

and abnormal pupil responses to light.

Diagnosis

On images produced by CT scans and MRIs, epidural hematomas usually appear convex in shape because their expansion

stops at the skull's sutures, where the dura mater is tightly attached to the skull. Thus they expand inward toward the brain

rather than along the inside of the skull, as occurs in subdural hematoma. The lens-like shape of the hematoma causes the

appearance of these bleeds to be "lentiform."

Epidural hematomas may occur in combination with subdural hematomas, or either may occur alone.

CT scans reveal subdural or epidural hematomas in 20% of unconscious patients. In the hallmark of epidural hematoma,

patients may regain consciousness and appear completely normal during what is called a lucid interval, only to descend

suddenly and rapidly into unconsciousness later. The lucid interval, which depends on the extent of the injury, is a key to

diagnosing epidural hemorrhage.

If the patient is not treated with prompt surgical intervention, death is likely to follow.

Hematoma

type Epidural

Subdural

v

t

e

Location Between the skull and the dura Between the dura and the arachnoid

Involved vessel

Temperoparietal locus (most likely) - Middle meningeal

artery

Frontal locus - anterior ethmoidal artery

Occipital locus - transverse or sigmoid sinuses

Vertex locus - superior sagittal sinus

Bridging veins

Symptoms Lucid interval followed by unconsciousness Gradually increasing headache and

confusion

CT appearance Biconvex lens Crescent-shaped

Causes

The interior of the skull has sharp ridges by which a

moving brain can be injured

The most common cause of intracranial epidural

hematoma is traumatic, although spontaneous

hemorrhage is known to occur.

Hemorrhages commonly result from acceleration-

deceleration trauma and transverse forces. The majority

of bleeds originate from meningeal arteries, particularly

in the temporal region. 10% of epidural bleeds may be

venous, due to shearing injury from rotational forces.

Epidural hematoma commonly results from a blow to

the side of the head.

The pterion region which overlies the middle meningeal

artery is relatively weak and prone to injury.

Thus only 20 to 30% of epidural hematomas occur

outside the region of the temporal bone.

The brain may be injured by prominences on the inside

of the skull as it scrapes past them.

Epidural hematoma is usually found on the same side of

the brain that was impacted by the blow, but on very rare

occasions it can be due to a contrecoup injury.

Treatment

As with other types of intracranial hematomas, the blood may be

removed surgically to remove the mass and reduce the pressure it

puts on the brain.

The hematoma is evacuated through a burr hole or craniotomy. If

transfer to a facility with neurosurgery is prolonged trephination

may be performed in the emergency department.

Prognosis

In TBI patients with epidural hematomas, prognosis is

better if there was a lucid interval (a period of

consciousness before coma returns) than if the patient was

comatose from the time of injury.

Unlike most forms of TBI, people with epidural hematoma

and a Glasgow Coma Score of 3 (the lowest score) are

expected to make a good outcome if they can receive

surgery quickly.

Of the spine

Bleeding into the epidural space in the spine may also

cause epidural hematoma. These may arise spontaneously

(e.g. during childbirth), or as a rare complication of

anaesthesia (such as epidural anaesthesia) or surgery (such

as laminectomy).

(VIDEO BELOW)

Epidural Hematoma.mp4

The anatomy of the epidural space means that spinal

epidural hematoma has a different profile from cranial

epidural hematoma.

In the spine, the epidural space contains loose fatty tissue,

and the epidural venous plexus, a network of large, thin-

walled veins.

This means that bleeding is likely to be venous.

Anatomical abnormalities and bleeding disorders make

these lesions more likely.

They may cause pressure on the spinal cord or cauda

equina, which may present as pain, muscle weakness, or

bladder and bowel dysfunction.

The diagnosis may be made on clinical appearance and

time course of symptoms.

It usually requires MRI scanning to confirm.

The treatment is surgical decompression.

The incidence of epidural hematoma following epidural

anaesthesia is extremely difficult to quantify; estimates

vary from 1 per 10,000 to 1 per 100,000 epidural

anaesthetics.

Additional Images

Nontraumatic epidural hematoma in a young woman. The grey area in the top left is organizing hematoma, causing

midline shift and compression of the ventricle.

Non-contrast CT Scan of a traumatic acute hematoma in the right fronto-temporal area