Extradural hematoma

Epidural hematoma
Epidural hematoma. Note the biconvex shape hemorrhage.
Classification and external resources
Specialty	Neurosurgery
ICD-10	I62.1, S06.4
ICD-9-CM	432.0
DiseasesDB	4353
MedlinePlus	001412
eMedicine	emerg/167 med/2898 neuro/574
Patient UK	Epidural hematoma
MeSH	D006407
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Epidural or extradural hematoma (haematoma), also known as an epidural hemorrhage, 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 spinal cord is also covered by a layer of dura mater, 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, compress delicate brain tissue, and cause brain shift. The condition is present in one to three percent of head injuries. Around 15–20% of epidural hematomas are fatal.

Epidural, 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.

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.

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Wikipedia