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Most cases reported in patients who are receiving some kind of anticoagulation therapy or who have a compromised coagulation.
Epidural hematoma refers to bleeding that occurs between the outer membrane covering the brain, the dura mater, and the skull.
The condition occurs in one to four percent of head injuries. Often associated with a loss of consciousness and other symptoms of confusion, vomiting, and an inability to move parts of the body.
Complications may include seizures.
Usual onset-of symptoms is rapid.
Causes include:
Head injury, bleeding disorder or blood vessel malformation.
Differential diagnosis: Subdural hematoma, subarachnoid hemorrhage, and traumatic brain injury
Typically head injury results in a break of the temporal bone and bleeding from the middle meningeal artery.
Occasionally it can occur as a result of a bleeding disorder or blood vessel malformation.
Diagnosis is typically made by a CT scan or MRI.
Treatment is generally by emergent surgery in the form of a craniotomy or burr hole.
Typically death will result if not treated.
Usually occurs in young adults.
Males are more often affected than females.
May present with a lucid period immediately following the trauma and a delay before symptoms become evident.
The epidural hematoma may compress intracranial structures which may impinge on the CN III, and cause a fixed and dilated pupil on the side of the injury to appear.
Epidural hematoma eye nerve compression causes the eye position to be down and out, due to unopposed CN IV and CN VI innervation.
Manifestations may include weakness of the extremities on the opposite side as the lesion due to compression of the crossed pyramid pathways.
There may be 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.
Tonsillar herniation can compromise medullary structures and lead to respiratory arrest.
Involvement of the trigeminal nerve (CN V) is late in the clinical process and unhelpful for diagnosis.
An epidural hematoma into the posterior cranial fossa can lead to tonsillar herniations and causes the Cushing’s triad of hypertension, bradycardia, and irregular respiration.
Because epidural bleeding is arterial it is rapid in nature.
Epidural bleeds grow until they reach their peak size at six to eight hours after injury.
Epidural bleeds can accumulate 25 to 75 cc’s of blood into the intracranial space.
Expansion of the hematoma strips the dura from the inside of the skull, resulting an intense headache.
The hematoma can become large and raise intracranial pressure, causing the brain to shift, impair its blood supply, or be crushed against the skull.
Larger hematomas can expand and compress the brainstem, causing unconsciousness, abnormal posturing, and abnormal pupil responses to light.
With trauma a moving brain can be injured by sharp bone ridges.
Hemorrhages can result from acceleration-deceleration injuries and transverse forces.
The majority of hemorrhagic bleeds originate from meningeal arteries, particularly in the temporal region.
Epidural bleeds may be venous in 10% of cases, and are due to shearing injury from rotational forces.
Epidural hematomas commonly are a result of a blow to the side of the head.
The pterion region overlies the middle meningeal artery is relatively weak and prone to injury.
Only 20 to 30% of epidural hematomas occur outside the region of the temporal bone.
Usually are found on the same side of the brain that was impacted by the blow.
Very rarely it can be due to a contrecoup injury.
Diagnostic images produced by CT scans and MRIs, epidural hematomas usually appear convex in shape.
Their expansion stops at the skull’s sutures, where the dura mater is tightly attached to the skull.
Epidural hematomas expand inward toward the brain rather than along the inside of the skull, as occurs in subdural hematoma, causing the appearance of these bleeds to be lentiform
They may occur in combination with subdural hematomas.
CT scans reveal subdural or epidural hematomas in 20% of unconscious patients.
Patients with epidural hematoma may regain consciousness and appear completely normal during a lucid interval, only to descend rapidly into unconsciousness later.
The primary key to diagnosis, depending on the extent of the injury, is the lucid period.
Prompt surgical intervention is required or death is likely to follow.
The blood clot mass must be removed surgically to reduce the pressure it puts on the brain.
It can be evacuated through a burr hole or craniotomy.
In patients with epidural hematomas, prognosis is better if there was a lucid interval than if the patient was comatose from the time of injury.
Patients with epidural hematoma and a Glasgow Coma Score of 15 are expected to make a good outcome if they can receive surgery quickly.