Common Types of Traumatic Brain Injury
Disorder | Clinical Findings | Diagnosis |
|---|---|---|
Acute subdural hematoma | Typically, acute neurologic dysfunction, which may be focal, nonfocal, or both With small hematomas, normal function possible | CT: Hyperdensity in subdural space, classically crescent-shaped Degree of midline shift important |
Basilar skull fracture | Leakage of cerebrospinal fluid (CSF) from the nose or ear Blood behind the tympanic membrane (hemotympanum) or in the external ear Ecchymosis behind the ear (Battle sign) or around the eye (raccoon eyes) | CT: Usually visible |
Brain contusion | Widely variable degrees of neurologic dysfunction or normal function | CT: Hyperdensities resulting from punctate hemorrhages of varied sizes |
Concussion | Transient mental status alteration (eg, loss of consciousness or memory) lasting < 6 hours | Based on clinical findings CT: By definition, no acute intracranial hemorrhage, lesions, or contusion present; there may be nondisplaced or minimally displaced linear skull fractures |
Chronic subdural hematoma | Gradual headache, somnolence, confusion, sometimes with focal deficits or seizures | CT: Hypodensity in subdural space (abnormality is isodense during subacute transition from hyperdense to hypodense) |
Diffuse axonal injury | Loss of consciousness lasting > 6 hours but no focal deficits or motor posturing | Based on clinical findings CT: At first, may be normal or show small hyperdensities (microhemorrhages) in corpus callosum, centrum semiovale, basal ganglia, or brain stem MRI: Multiple small microhemorrhages in deep white matter or subcortical areas and brain stem |
Epidural hematoma | Headache, impaired consciousness within hours, sometimes with a lucid interval Herniation typically causing contralateral hemiparesis and ipsilateral pupillary dilation | CT: Hyperdensity in epidural space, classically lenticular-shaped and located over the middle meningeal artery (temporal fossa) due to a temporal bone fracture |
Subarachnoid hemorrhage | Typically, normal neurologic examination Occasionally, acute neurologic dysfunction | CT: Hyperdensity within subarachnoid space on the surface of the brain; often lining the sulci |