Epidural hematoma
Template:Short description Template:Infobox medical condition (new) Epidural hematoma is when bleeding occurs between the tough outer membrane covering the brain (dura mater) and the skull.<ref name=New2009>Template:Cite book</ref> When this condition occurs in the spinal canal, it is known as a spinal epidural hematoma.<ref name=New2009/>
There may be loss of consciousness following a head injury, a brief regaining of consciousness, and then loss of consciousness again.<ref name=Po2009>Template:Cite book</ref> Other symptoms may include headache, confusion, vomiting, and an inability to move parts of the body.<ref name=Fer2017/> Complications may include seizures.<ref name=Fer2017/>
The cause is typically a head injury that results in a break of the temporal bone and bleeding from the middle meningeal artery.<ref name=New2009/> Occasionally it can occur as a result of a bleeding disorder or blood vessel malformation.<ref name=Fer2017/> Diagnosis is typically by a CT scan or MRI scan.<ref name=Fer2017/>
Treatment is generally by urgent surgery in the form of a craniotomy or burr hole,<ref name=Fer2017/> or (in the case of a spinal epidural hematoma) laminotomy with spinal decompression.
The condition occurs in one to four percent of head injuries.<ref name=Fer2017/> Typically it occurs in young adults.<ref name=Fer2017/> Males are more often affected than females.<ref name=Fer2017>Template:Cite book</ref>
Signs and symptomsEdit
Many people with epidural hematomas experience a lucid period immediately following the injury, with a delay before symptoms become evident.<ref name=medscape/> Because of this initial period of lucidity, it has been called "Talk and Die" syndrome.<ref>{{#invoke:citation/CS1|citation |CitationClass=web }}</ref> 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.<ref name=medscape>Epidural Hematoma in Emergency Medicine at Medscape. Author: Daniel D Price. Updated: Nov 3, 2010</ref> The eye will be positioned down and out due to unopposed innervation of the fourth and sixth cranial nerves.Template:Cn
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.<ref name="Kha2018" />
If not treated promptly, epidural hematomas can cause tonsillar herniation, resulting in respiratory arrest. 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.<ref>Wagner AL. 2006. "Subdural Hematoma." Emedicine.com. Retrieved on February 6, 2007.</ref> In the case of epidural hematoma in the posterior cranial fossa, tonsillar herniation causes Cushing's triad: hypertension, bradycardia, and irregular breathing.Template:Cn
CausesEdit
The most common cause of intracranial epidural hematoma is head injury, although spontaneous hemorrhages have been known to occur. Epidural hematomas occur in about 10% of traumatic brain injuries, mostly due to car accidents, assaults, or falls.<ref name="Kha2018" /> They are often caused by acceleration-deceleration trauma and transverse forces.<ref name="uv">University of Vermont College of Medicine. "Neuropathology: Trauma to the CNS.", March 2005, Retrieved on February 6, 2007.</ref><ref name="McCaffrey">McCaffrey P. 2001. "The Neuroscience on the Web Series: CMSD 336 Neuropathologies of Language and Cognition." Template:Webarchive California State University, Chico. Retrieved on February 6, 2007.</ref>
Epidural hematoma commonly results from a blow to the side (temporal bone) of the head. The pterion region, which overlies the middle meningeal artery, is relatively weak and prone to injury.<ref name="Shepherd">Shepherd S. 2004. "Head Trauma." Emedicine.com. Retrieved on February 6, 2007.</ref> Only 20 to 30% of epidural hematomas occur outside the region of the temporal bone.<ref>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.</ref> 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 which was impacted by the blow, but on very rare occasions it can be due to a contrecoup injury.<ref name="Mishra">Template:Cite journal</ref>
A "heat hematoma" is an epidural hematoma caused by severe thermal burn, causing contraction and exfoliation of the dura mater and exfoliate from the skull, in turn causing exudation of blood from the venous sinuses.<ref name="KawasumiUsui2013">Template:Cite journal</ref> The hematoma can be seen on autopsy as brick red, or as radiolucent on CT scan, because of heat-induced coagulation of the hematoma.<ref name="KawasumiUsui2013"/>
PathophysiologyEdit
The break of the temporal bone causes bleeding from the middle meningeal artery, <ref name=New2009/> hence epidural bleeding is often rapid as arteries are high-pressure flow. In 10% of cases, however, it comes from veins and can progress more slowly.<ref name="Shepherd" /> A venous hematoma may be acute (occurring within a day of the injury and appearing as a swirling mass of blood without a clot), subacute (occurring in 2–4 days and appearing solid), or chronic (occurring in 7–20 days and appearing mixed or lucent).<ref name=Kha2018 />
In adults, the temporal region accounts for 75% of cases. In children, however, they occur with similar frequency in the occipital, frontal, and posterior fossa regions.<ref name="Kha2018" /> Epidural bleeds from arteries can grow until they reach their peak size 6–8 hours post-injury, spilling 25–75 cubic centimeters of blood into the intracranial space.<ref name="uv" /> As the hematoma expands, it strips the dura from the inside of the skull, causing an intense headache. It also increases intracranial pressure, causing the brain to shift, lose blood supply, be crushed against the skull, or herniate. Larger hematomas cause more damage. Epidural bleeds can quickly compress the brainstem, causing unconsciousness, abnormal posturing, and abnormal pupil responses to light.<ref name="singh Stock">Singh J and Stock A. 2006. "Head Trauma." Emedicine.com. Retrieved on February 6, 2007.</ref>
DiagnosisEdit
Diagnosis is typically by CT scan or MRI.<ref name="Fer2017" /> MRIs have greater sensitivity and should be used if there is a high suspicion of epidural hematoma and a negative CT scan.<ref name="Kha2018" /> Differential diagnoses include a transient ischemic attack, intracranial mass, or brain abscess.<ref name="Kha2018" />
Epidural hematomas usually appear convex in shape because their expansion stops at the 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 hematomas. Most people also have a skull fracture.<ref name="Kha2018" />
Epidural hematomas may occur in combination with subdural hematomas, or either may occur alone.<ref name="Shepherd"/> CT scans reveal subdural or epidural hematomas in 20% of unconscious people.<ref name="Downie">Downie A. 2001. "Tutorial: CT in Head Trauma" Template:Webarchive. Retrieved on February 6, 2007.</ref> In the hallmark of epidural hematoma, people may regain consciousness and appear completely normal during what is called a lucid interval, only to descend suddenly and rapidly into unconsciousness later. This lucid interval, which depends on the extent of the injury, is a key to diagnosing an epidural hematoma.<ref name=Kha2018 />
- Epidural hematoma.png
Nontraumatic epidural hematoma in a young woman. The grey area in the top right is organizing hematoma, causing midline shift and compression of the ventricle.
- Traumatic acute epidual hematoma.jpg
Non-contrast CT scan of a traumatic acute hematoma in the right fronto-temporal area.
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A diagram showing an epidural hematoma.
TreatmentEdit
Epidural hematoma is a surgical emergency. Delayed surgery can result in permanent brain damage or death. Without surgery, death usually follows, due to enlargement of the hematoma, causing a brain herniation.<ref name=Kha2018 /> As with other types of intracranial hematomas, the blood almost always must be removed surgically to reduce the pressure on the brain.<ref name="McCaffrey"/> The hematoma is evacuated through a burr hole or craniotomy. If transfer to a facility with neurosurgery is unavailable, prolonged trephination (drilling a hole into the skull) may be performed in the emergency department.<ref>Template:Cite journal</ref> Large hematomas and blood clots may require an open craniotomy.<ref name=":0">{{#invoke:citation/CS1|citation |CitationClass=web }}</ref>
Medications may be given after surgery. They may include antiseizure medications and hyperosmotic agents to reduce brain swelling and intracranial pressure.<ref name=":0" />
It is extremely rare to not require surgery. If the volume of the epidural hematoma is less than 30 mL, the clot diameter less than 15 mm, a Glasgow Coma Score above 8, and no visible neurological symptoms, then it may be possible to treat it conservatively. A CT scan should be performed, and watchful waiting should be done, as the hematoma may suddenly expand.<ref name="Kha2018"/>
PrognosisEdit
The prognosis is better if there was a lucid interval than if the person was comatose from the time of injury. Arterial epidural hematomas usually progress rapidly. However, venous epidural hematomas, caused by a dural sinus tear, are slower.<ref name="Kha2018" />
Outcomes are worse if there is more than 50 mL of blood in the hematoma before surgery. Age, pupil abnormalities, and Glasgow Coma Scale score on arrival to the emergency department also influence the prognosis. In contrast to most forms of traumatic brain injury, people with epidural hematoma and a Glasgow Coma Score of 15 (the highest score, indicating the best prognosis) usually have a good outcome if they receive surgery quickly.<ref name="Kha2018" />
EpidemiologyEdit
About 2 percent of head injuries and 15 percent of fatal head injuries involve an epidural hematoma. The condition is more common in teenagers and young adults than in older people, because the dura mater sticks more to the skull as a person ages, reducing the probability of a hematoma forming. Males are affected more than females.<ref name="Kha2018" />
ReferencesEdit
External linksEdit
Template:Medical resources Template:Injuries, other than fractures, dislocations, sprains and strains Template:Neurotrauma Template:Cerebrovascular diseases