148
Trauma
Answers
124.The answer is a.(Moore, pp 385-401.)The patient sustained a
cerebral concussion.This is caused by a head injury leading to a brief loss
of neurologic function. These individuals are often amnestic to the event
and frequently ask the same questions over and over again (perseverations).
Headache with or without vomiting is generally present; however, there are
no focal neurologic findings on examination. Loss of consciousness results
from impairment of the reticular activating system. Patients show rapid clin-
ical improvement. CT scan is normal.
Diffuse axonal injury (b)is caused by microscopic shearing of brain
nerve fibers. Patients typically present unconscious and remain in a coma
for a prolonged period of time. Although the CT scan does not show a mass
lesion, patients have over a 33% mortality rate. The clinical features of a
cerebral contusion (c)are similar to those of a concussion except neuro-
logic dysfunction is more profound and prolonged and focal deficits may
be present if contusions occur in the sensorimotor area. These injuries
occur when the brain impacts the skull. The lesion is typically seen on CT
scan. Posttraumatic epilepsy (d)is associated with intracranial hematomas
and depressed skull fractures. The seizures generally occur within the first
week of the head injury. Some scientists believe that head trauma predis-
poses to Alzheimer disease (e); however, this would take years to develop.
125.The answer is b.(Moore, pp 564-567.)Blunt cardiac injuries usu-
ally result from high-speed vehicular collisions in which the chest wall
strikes the steering wheel. Although they are all associated with potentially
fatal complications, they should be viewed clinically as a continuous spec-
trum of myocardial damage: concussion (no permanent cell damage), contu-
sion (permanent cell damage), infarction (cell death), tamponade (bleeding
into the pericardium), and rupture (exsanguination). The mechanism of
injury in a cardiac contusion involves a high-speed deceleration, which
causes the heart to move forward, forcibly striking the sternum. In addition,
the direct force of hitting an object (eg, the steering wheel) also can damage