Epidural hematoma is when bleeding occurs between the dura mater (dura mater) and the skull.[
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There may be unconsciousness following a head injury, a brief regaining of consciousness, and then loss of consciousness again.[ Complications may include .][
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The cause is typically a head injury that results in a break of the temporal bone and bleeding from the middle meningeal artery.[ Occasionally it can occur as a result of a coagulopathy or blood vessel malformation.][ Diagnosis is typically by a CT scan or MRI scan.][
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Treatment is generally by urgent surgery in the form of a craniotomy or Trepanning,[ or (in the case of a spinal epidural hematoma) laminotomy with spinal decompression.
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The condition occurs in one to four percent of head injury.[ Typically it occurs in young adults.][ Males are more often affected than females.]
Signs and symptoms
Many people with epidural hematomas experience a lucid period immediately following the injury, with a delay before symptoms become evident.[ Because of this initial period of lucidity, it has been called "Talk and Die" syndrome.][ Epidural Hematoma in Emergency Medicine at Medscape. Author: Daniel D Price. Updated: Nov 3, 2010] The eye will be positioned down and out due to unopposed innervation of the Trochlear nerve and Abducens nerve.
Other symptoms include severe headache; weakness of the extremities on the opposite side from the lesion due to compression of the Pyramidal tracts; and vision loss, also on the opposite side, due to compression of the posterior cerebral artery. In rare cases, small hematomas may be asymptomatic.
If not treated promptly, epidural hematomas can cause tonsillar herniation, resulting in respiratory arrest. The trigeminal nerve may be involved late in the process as the pons is compressed, but this is not an important presentation, because the person may already be dead by the time it occurs.[Wagner AL. 2006. "Subdural Hematoma." Emedicine.com. Retrieved on February 6, 2007.] In the case of epidural hematoma in the posterior cranial fossa, tonsillar herniation causes Cushing's triad: hypertension, bradycardia, and irregular breathing.
Causes
The most common cause of intracranial epidural hematoma is head injury, although spontaneous hemorrhages have been known to occur. Epidural hematomas occur in about 10% of traumatic brain injuries, mostly due to car accidents, assaults, or falls.[University of Vermont College of Medicine. "Neuropathology: Trauma to the CNS.", March 2005, Retrieved on February 6, 2007.][McCaffrey P. 2001. "The Neuroscience on the Web Series: CMSD 336 Neuropathologies of Language and Cognition." California State University, Chico. Retrieved on February 6, 2007.]
Epidural hematoma commonly results from a blow to the side (temporal bone) of the head. The pterion region, which overlies the middle meningeal artery, is relatively weak and prone to injury.[Shepherd S. 2004. "Head Trauma." Emedicine.com. Retrieved on February 6, 2007.] Only 20 to 30% of epidural hematomas occur outside the region of the temporal bone.[Graham DI and Gennareli TA. Chapter 5, "Pathology of Brain Damage After Head Injury" Cooper P and Golfinos G. 2000. Head Injury, 4th Ed. Morgan Hill, New York.] 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.
A "heat hematoma" is an epidural hematoma caused by severe thermal burn, causing contraction and exfoliation of the dura mater and exfoliate from the skull, in turn causing exudation of blood from the venous sinuses.
Pathophysiology
The break of the temporal bone causes bleeding from the middle meningeal artery,[ hence epidural bleeding is often rapid as Artery are high-pressure flow. In 10% of cases, however, it comes from and can progress more slowly.]
In adults, the temporal region accounts for 75% of cases. In children, however, they occur with similar frequency in the Occipital lobe, Frontal lobe, and posterior fossa regions.[Singh J and Stock A. 2006. "Head Trauma." Emedicine.com. Retrieved on February 6, 2007.]
Diagnosis
Diagnosis is typically by CT scan or MRI.
Epidural hematomas usually appear convex in shape because their expansion stops at the skull's skull suture, 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 hematomas. Most people also have a skull fracture.
Epidural hematomas may occur in combination with subdural hematomas, or either may occur alone.[Downie A. 2001. "Tutorial: CT in Head Trauma" . Retrieved on February 6, 2007.] In the hallmark of epidural hematoma, people may regain consciousness and appear completely normal during what is called a lucid interval, only to descend suddenly and rapidly into unconsciousness later. This lucid interval, which depends on the extent of the injury, is a key to diagnosing an epidural hematoma.
File:Epidural hematoma.png|Nontraumatic epidural hematoma in a young woman. The grey area in the top right is organizing hematoma, causing midline shift and compression of the ventricle.
File:Traumatic acute epidual hematoma.jpg|Non-contrast CT scan of a traumatic acute hematoma in the right fronto-temporal area.
File:Hematoma.png|A diagram showing an epidural hematoma.
Treatment
Epidural hematoma is a surgical emergency. Delayed surgery can result in permanent brain damage or death. Without surgery, death usually follows, due to enlargement of the hematoma, causing a brain herniation.
Medications may be given after surgery. They may include antiseizure medications and hyperosmotic agents to reduce brain swelling and intracranial pressure.
It is extremely rare not to require surgery. If the volume of the epidural hematoma is less than 30 mL, the clot diameter is less than 15 mm, a Glasgow Coma Score above 8, and no visible neurological symptoms, then it may be possible to treat it conservatively. A CT scan should be performed, and watchful waiting should be done, as the hematoma may suddenly expand.
Prognosis
The prognosis is better if there was a lucid interval than if the person was comatose from the time of injury. Arterial epidural hematomas usually progress rapidly. However, venous epidural hematomas, caused by a dural sinus tear, are slower.
Outcomes are worse if there is more than 50 mL of blood in the hematoma before surgery. Age, pupil abnormalities, and Glasgow Coma Scale score on arrival to the emergency department also influence the prognosis. In contrast to most forms of traumatic brain injury, people with epidural hematoma and a Glasgow Coma Score of 15 (the highest score, indicating the best prognosis) usually have a good outcome if they receive surgery quickly.
Epidemiology
About 2 percent of head injuries and 15 percent of fatal head injuries involve an epidural hematoma. The condition is more common in teenagers and young adults than in older people, because the dura mater sticks more to the skull as a person ages, reducing the probability of a hematoma forming. Males are affected more than females.
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