DefenitionAn epidural hematoma is caused from bleeding between the skull and the outer membrane that covers the brain (dura mater). Rapid bleeding results in a localized accumulation of blood (hematoma) that presses on the brain tissue and leads to a rapid increase in pressure within the brain (increased intracranial pressure). FrequencyUnited StatesEpidural hematoma occurs in 1-2% of all head trauma cases and in about 10% of patients who present with traumatic coma.Mortality/MorbidityReported mortality rates range from 5-43%.Higher rates are associated with the following: Advanced age Intradural lesions Temporal location Increased hematoma volume Rapid clinical progression Pupillary abnormalities Increased intracranial pressure (ICP) Lower Glasgow coma scale (GCS)Mortality rates are essentially nil for patients not in coma preoperatively and approximately 10% for obtunded patients and 20% for patients in deep coma. AgePatients younger than 5 years and older than 55 years have an increased mortality rate.Patients younger than 20 years account for 60% of EDHs.EDH is uncommon in elderly patients because the dura is strongly adhered to the inner table of the skull. In case series of EDH, fewer than 10% of patients are older than 50 years. PrognosisIf the diagnosis is recognized immediately and surgery is performed, the outcome is generally good. If the individual is first seen during the lucid period, a CT may not be done because an epidural hematoma is not suspected. If the diagnosis and treatment of epidural hematoma are therefore delayed, incidence of death or long-term neurologic deficits increases. The mortality rate of epidural hematomas is between 5% and 50%.

Outcome after surgical evacuation of an epidural hematoma is directly related to the level of consciousness before surgery. An outcome study on individuals with epidural hematoma suggests that 23% have a poor outcome, and 77% have good recovery to moderate disability following surgery (Bradley).