epidural hematoma

2% of all serious head injuries
uncommon in infants
associated with skull fracture in 40-85%
mechanism of injury:
- laceration of dural vessels from calvarium fracture (91%)
- avulsion of venous vessels from points of calvarial perforations
- disruption of dural sinuses (major cause in kids)
transient loss of consciousness; lucent interval
3rd nerve palsy (sign of cerebral herniation)
somnolence 24-96 hrs after accident (medical emergency)
types:
- acute (58%) from arterial bleeding
- subacute (31%)
- chronic (11%) from venous bleeding
location:
1. temporoparietal (66%): middle meningeal artery tear
2. frontal pole, parieto-occipital region, between occipital lobes, posterior fossa: laceration of venous sinuses