As blood accumulates, it starts to compress intracranial structures, which may impinge on the third cranial nerve ,  causing a fixed and dilated pupil on the side of the injury. Other symptoms include severe headache ; weakness of the extremities on the opposite side from the lesion due to compression of the crossed pyramid pathways ; and vision loss, also on the opposite side, due to compression of the posterior cerebral artery. In rare cases, small hematomas may be asymptomatic. 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. Causes[ edit ] The interior of the skull has sharp ridges by which a moving brain can be injured.
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An extradural hematoma is actually a subperiosteal hematoma located on the inside of the skull, between the inner table of the skull and parietal layer of the dura mater which is the periosteum. As a result, EDHs are usually limited in their extent by the cranial sutures, as the periosteum crosses through the suture continuous with the outer periosteal layer.
This is therefore helpful in distinguishing EDHs from subdural hematomas , which are not limited by sutures. Extradural hemorrhages can, however, cross and elevate venous sinuses as long as there is no suture there; after all a venous sinus is located between the parietal and visceral layer of the dura.
Unfortunately, these rules are not foolproof and not infrequently extradural hematomas do cross sutures. They are typically bi-convex or lentiform in shape, and most frequently beneath the squamous part of the temporal bone.
EDHs are hyperdense, somewhat heterogeneous, and sharply demarcated. Depending on their size, secondary features of mass effect e. Postcontrast extravasation may be seen rarely in case of acute EDH and peripheral enhancement due to granulation and neovascularization can be seen in chronic EDH.
MRI MRI can clearly demonstrate the displaced dura that appears as a hypointense line on T1 and T2 sequences which is helpful in distinguishing it from a subdural hematoma. Acute EDH appears isointense on T1 and shows variable intensities from hypo- to hyperintense on a T2 sequence. Intravenous contrast may demonstrate displaced or occluded venous sinus in case of the venous origin of EDH.
Angiography It can be used to evaluate nontraumatic cause i. Rarely angiography can demonstrate middle meningeal artery laceration and contrast extravasation from the middle meningeal artery into paired middle meningeal veins known as "tram track sign". Treatment and prognosis Prognosis, even with a relatively large hematoma, is in general quite good, as long as the clot is evacuated promptly.
A smaller hematoma without mass effect or swirl sign can be treated conservatively 2, sometimes resulting in calcification of the dura. Occasionally late complications are encountered, usually relating to the injured meningeal vessel. They include: arteriovenous fistula Differential diagnosis With large hematomas, there is rarely significant confusion as to the correct diagnosis.
In smaller lesions, especially when there is associated parenchymal injury e. Differential considerations include:.
HEMATOMA EPIDURAL OU EXTRADURAL