epidural hematoma

Classification and external resources 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. ICD-10 I62.1, S06.4 ICD-9 432.0 DiseasesDB 4353 MedlinePlus 001412 eMedicine emerg/167 med/2898 neuro/574 MeSH D006407

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. The dura mater also covers the spine, so epidural bleeds may also occur in the spinal column. 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. The condition is present in one to three percent of head injuries.[1] Between 15 and 20% of patients with epidural hematomas die of the injury.[2] Contents [hide] 1 Causes 2 Features 3 Treatment 4 Prognosis 5 Epidural hematoma in the spine 6 Notable cases 7 References 8 External links //

Causes The interior of the skull has sharp ridges by which a moving brain can be injured.

The cause of epidural hematoma is usually traumatic, although spontaneous hemorrhage is known to occur. Hemorrhages commonly result from acceleration-deceleration trauma and transverse forces.[3][4] 10% of epidural bleeds may be venous.[5] 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. The pterion region which overlies the middle meningeal artery is exceptionally weak and prone to injury. [5] Thus only 20 to 30% of epidural hematomas occur outside the region of the temporal bone.[6]

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.[1]

Features

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.[7]

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.[3] 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