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Epidural hematomapng
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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
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or '''extradural hematoma''' is a buildup of blood occurring between the
Dura Mater (the
Brain's tough outer membrane) and the
Skull . Often due to
Trauma , the condition is potentially deadly because the buildup of blood may increase
Pressure in the
Intracranial Space and compress delicate brain tissue. 15 to 20% of patients with epidural hematomas die of the
Injury (Sanders and McKenna, 2001).
The cause of epidural hematoma is usaully
Traumatic , although spontaneous hemorrhage is known to occur. Hemorrhages commonly result from
Acceleration-deceleration Trauma and transverse forces (McCaffrey, 2001; University of Vermont).
Venous epidural bleeds are usually due to
Shearing Injury from
Rotational or linear forces, caused when tissues of different densities slide over one another.
Epidural hematoma commonly results from a blow to the side of the head and is frequently caused by a fracture that passes through an arterial channel in the
Bone , most commonly a break in
Temporal Bone interrupting
Middle Meningeal Artery , a branch of the
External Carotid (Shepherd, 2004). Thus only 20 to 30% of epidural hematomas occur outside the temporal bone (Graham and Gennareli, 2000).
Epidural bleeds, like
Subdural and
Subarachnoid Hemorrhage s, are
Extra-axial Bleeds , occurring outside of the brain tissue, while
Intra-axial Hemorrhage s, including
Intraparenchymal and
Intraventricular Hemorrhage s, occur within it (Wagner, 2004).
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 Centimeter s of blood into the
Intracranial Space (University of Vermont; Stock and Singer, 2004). 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 (Stock and Singer, 2004).
10% of epidural bleeds may be venous (Shepherd, 2004).
On images produced by
CT Scan s and
MRI s, epidural hematomas usually appear convex in shape because their expansion stops at 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 leads the appearance of these bleeds to be called "lentiform".
Epidural hematomas may occur in combination with subdural hematomas, or either may occur alone (Shepherd, 2004). CT scans reveal subdural or epidural hematomas in 20% of unconscious patients (Downie, 2001).
In the hallmark of epidural hematoma, patients may regain consciousness 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 (Caroline).
As with other types of
Intracranial Hematoma s, the blood may be aspirated surgically to remove the mass and reduce the pressure it puts on the brain (McCaffrey, 2001). The hematoma is
Neurosurgically evacuated through a
Burr Hole or
Craniotomy . The diagnosis of epidural hematoma requires a patient to be cared for in a facility with a neurosurgeon on call to decompress the hematoma if necessary and stop the bleed by ligating the injured vessel branches.
# Caroline NL. 1991. ''Emergency Medical Treatment''. Little Brown & Company.
# Downie A. 2001.
"Tutorial: CT in Head Trauma" .
# 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.
# McCaffrey P. 2001.
"The Neuroscience on the Web Series: CMSD 336 Neuropathologies of Language and Cognition." California State University, Chico.
# Sanders MJ and McKenna K. 2001. ''Mosby’s Paramedic Textbook'', 2nd revised Ed. Chapter 22, "Head and Facial Trauma." Mosby.
# Shepherd S. 2004.
"Head Trauma." Emedicine.com
# Stock A and Singer L. 2004.
"Head Trauma." Emedicine.com.
#University of Vermont College of Medicine.
"Neuropathology: Trauma to the CNS."
# Wagner AL. 2004.
"Subdural Hematoma." Emedicine.com.
