|
Epidural Hematoma |
Subdural Hematoma |
Common mechanism |
Blunt direct trauma, frequently to parietal or temporal regions, lower forces |
Acceleration-deceleration injury, direct trauma, higher forces |
Etiology |
Arterial or venous (bleed between skull and dura) |
Venous (bridging veins between dura and arachnoid membranes) |
Incidence |
Uncommon |
Common |
Peak age |
Usually >2 yr |
Usually >1 yr, peak at 6 mo |
Location |
Unilateral, commonly parietal |
75% Bilateral, diffuse, over cerebral hemispheres |
Skull fracture |
Common |
Uncommon |
Associated seizures |
Uncommon |
Common |
Retinal hemorrhages |
Rare |
Common |
Decreased level of consciousness |
Common |
Almost always (50% present in coma) |
Mortality |
Rare |
Uncommon |
Morbidity in survivors |
Low |
High, due to associated underlying brain injury |
Other clinical findings |
Dilated ipsilateral pupil, contralateral hemiparesis |
Decreased level of consciousness |
|
Period of lucidity prior to acute decompensation and rapid progression to herniation (only 20%) |
Headaches, irritability, emesis |
Onset |
Acute |
Acute (within 24 hr), subacute (within 1 d to 2 wk), or chronic (after 2 wk) |
Findings on computed tomography |
Lentiform “lens-shaped,” usually not crossing suture lines |
Lunar “crescent shaped,” often not crossing midline (due to falx cerebri) |