Excerpt from Epidural Hematoma


Synonyms, Key Words, and Related Terms: epidural hemorrhage, extradural hematoma, extradural hemorrhage, cerebral epidural hematoma, spinal epidural hematoma, EDH, SEDH, head injury, intracranial epidural hematoma

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Background: Epidural hematoma (ie, accumulation of blood in the potential space between dura and bone) may be intracranial (EDH) or spinal (SEDH). EDH occurs in approximately 2% of patients with head injuries and 5-15% of patients with fatal head injuries. EDH is considered to be the most serious complication of head injury, requiring immediate diagnosis and surgical intervention. EDH may be acute (58%), subacute (31%), or chronic (11%). SEDH may also be traumatic, though it may occur spontaneously.

Pathophysiology: Epidural hematoma usually results from a brief linear contact force to the calvaria that causes separation of the periosteal dura from bone and disruption of interposed vessels due to shearing stress. Skull fractures occur in 85-95% of adult cases, but they are much less common in children because of the plasticity of the immature calvaria. Arterial or venous structures may be compromised, causing rapid expansion of the hematoma; however, chronic or delayed manifestations may occur when venous sources are involved. Extension of the hematoma usually is limited by suture lines owing to the tight attachment of the dura at these locations.

The temporoparietal region and the middle meningeal artery are involved most commonly (66%), although the anterior ethmoidal artery may be involved in frontal injuries, the transverse or sigmoid sinus in occipital injuries, and the superior sagittal sinus in trauma to the vertex. Bilateral epidural hematomas account for 2-10% of all acute epidural hematomas in adults but are exceedingly rare in children. Posterior fossa epidural hematomas represent 5% of all cases of epidural hematomas.

SEDH may be spontaneous or may follow minor trauma, such as lumbar puncture or epidural anesthesia. Spontaneous SEDH may be associated with anticoagulation, thrombolysis, blood dyscrasias, coagulopathies, thrombocytopenia, neoplasms, or vascular malformations. The peridural venous plexus usually is involved, though arterial sources of hemorrhage also occur. The dorsal aspect of the thoracic or lumbar region is involved most commonly, with expansion limited to a few vertebral levels.

Frequency:

  • In the US: Epidural hematoma complicates 2% of cases of head trauma (approximately 40,000 cases per year). SEDH affects 1 per 1,000,000 people annually. Alcohol and other forms of intoxication have been associated with a higher incidence of epidural hematoma.
  • Internationally: International frequency is unknown, though it is likely to parallel the frequency in the United States.

Mortality/Morbidity: Mortality rate associated with epidural hematoma has been estimated to be 5-50%.

  • The level of consciousness prior to surgery has been correlated with mortality rate: 0% for awake patients, 9% for obtunded patients, and 20% for comatose patients.
  • Bilateral EDH has a mortality rate of 15-20%.
  • Posterior fossa epidural hematoma has a mortality rate of 26%.

Race: No racial predilection has been reported.

Sex: EDH and SEDH are more frequent in men, with a male-to-female ratio of 4:1.

Age:

  • EDH is rare in individuals younger than 2 years.
  • EDH is also rare in individuals older than 60 years because the dura is tightly adherent to the calvaria.
  • SEDH has a bimodal distribution with peaks during childhood and during the fifth and sixth decades of life. Increasing age has been noted as a risk factor for postoperative SEDH. Please click here to view the full topic text: Epidural Hematoma