subdural hematoma

incidence: 5% of head trauma patients
age: infants and elderly (large subarachnoid space with freedom to move)
cause: damage to subdural veins ("bridging veins")
acute subdural hematoma:
- manifests hours after injury
- hyperdense (<1 week); isodense (1-3 weeks); hypodense (3-4 weeks)
- underlying brain injury (50%)
- worse long term prognosis than epidural hematoma
chronic subdural hematoma
- following minor injury; rarely parenchymal injury
- convex configuration (unlike acute subdural)
interhemispheric subdural hematoma
- most common acute finding in child abuse (whiplash injury)
- predominace for posterior portion of interhemispheric fissure