Contributed by: Yousuf Qaseem, University of New Mexico School of Medicine, 1 University of New Mexico, Albuquerque, NM 87131
- Epidural hematomas are a subtype of intracranial hemorrhage due to arterial bleeding between the dura and the skull. Their clinical presentation is characterized by a “lucid interval” prior to potentially catastrophic neurological sequelae and imaging shows a “biconvex shaped” blood collection.
| Etiology and Pathogenesis |
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- Epidural hematomas are arterial hemorrhages often associated with traumatic head injury. Fracture of the temporal bone and consequent rupture of the middle meningeal artery results in collection of blood between the dura and the skull. Importantly, because the dura has attachments at the suture lines of the skull, arterial blood cannot spread beyond these boundaries and thus develops into a classically described “biconvex lens” shape that can be appreciated on non-contrast CT of the brain. This blood collection can create a mass effect, yielding midline shift of the brain and ventricular compression. If the hematoma is large enough, uncal or tonsillar herniation can occur.
| Clinical Features and Consequences |
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- The classical history of an epidural hematoma is loss of consciousness after a closed head injury, followed by a “lucid interval”. During this interval, the patient may be awake and alert, but rapid deterioration leading to stupor, coma, and death can occur over minutes to hours.
- As with many types of intracranial hemorrhage, the gravest consequences are the result of severely elevated intracranial pressure (ICP). With elevated ICP, patients may exhibit the Cushing reflex, a triad of hypertension, bradycardia and respiratory depression. Other symptoms of increased ICP include headache, severe nausea and projectile vomiting. With uncorrected elevated ICP, uncal or tonsillar herniation can occur, leading to brainstem compression. This can result in respiratory arrest, coma, and death. Evidence of herniation may be found in a fixed, dilated (“blown”) pupil, reflecting ipsilateral cranial nerve III compression by the uncus. Emergent evacuation of the hematoma is often necessary to prevent these sequelae.
- Naidech AM. 2011. "Intracranial Hemorrhage." American Journal of Respiratory and Critical Care Medicine 184.9 (2011): 998-1006
Qaseem, Y, “Epidural Hematoma” in Pathway Medicine: An Introduction to Clinical Medicine", PathwayMedicine.org (2017).