PHYS 799 Lecture Notes - Lecture 14: Focal Neurologic Signs, Diffuse Axonal Injury, Middle Meningeal Artery
23 Apr 2019
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Patients lucid for several hrs before neurologic signs appear. Coup injury injury at the site of impact. Contrecoup injury injury opposite the site of impact. Contusion (i. e. bruise) hemorrhage, tissue injury, edema; incl. both coup and contrecoup. Crests of gyri, orbitofrontal region, and temporal lobe tips most commonly affected. Penetration injury laceration tissue tearing, vascular disruption, hemorrhage. Concussion reversible altered consciousness, temp. respiratory arrest, reflex loss, w/o contusion; recovery typically complete. Contusions wedge-shaped (widest at impact point), neuronal injury not visible until 24 hrs after; superficial layers affected most severely. Older lesions depressed, retracted, yellow-brown patches on crests of gyri; in severe cases, may be cavitary lesions; gliosis and macrophages w/hemosiderin present. Diffuse axonal injury also possible often near lateral ventricles and brain stem; axonal swelling visible. Epidural hematoma usually damage to middle meningeal artery, from skull displacement (infants) or skull fractures (children/adults); arterial pressure dissects dura from skull.
