Diagnosis
| Hematoma type | Epidural | Subdural |
|---|---|---|
| Location | Between the skull and the dura | Between the dura and the arachnoid |
| Involved vessel | Temperoparietal locus (most likely) - Middle meningeal artery Frontal locus - anterior ethmoidal artery Occipital locus - transverse or sigmoid sinuses Vertex locus - superior sagittal sinus |
Bridging veins |
| Symptoms | Lucid interval followed by unconsciousness | Gradually increasing headache and confusion |
| CT appearance | Biconvex lens | Crescent-shaped |
On images produced by CT scans and MRIs, 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 hematoma. The lens-like shape of the hematoma causes the appearance of these bleeds to be "lentiform."
Epidural hematomas may occur in combination with subdural hematomas, or either may occur alone. CT scans reveal subdural or epidural hematomas in 20% of unconscious patients. In the hallmark of epidural hematoma, patients may regain consciousness and appear completely normal during what is called a lucid interval, only to descend suddenly and rapidly into unconsciousness later. The lucid interval, which depends on the extent of the injury, is a key to diagnosing epidural hemorrhage. If the patient is not treated with prompt surgical intervention, death is likely to follow.
Read more about this topic: Epidural Hematoma