CENTRAL NERVOUS SYSTEM TRAUMA
Section I. HEAD INJURY
Few nonfatal injuries cause such devastating physical and psychological effects
as trauma to the central nervous system. In many cases, irreversible damage occurs
regardless of the care the victim receives. In a significant number of cases, however,
the initial care administered determines the ultimate outcome of the case. In fact, in
such "treatable" patients, the emergency management is frequently more important than
all subsequent efforts. This statement should trigger in your mind the importance of
your role in the evaluation and initial care of these patients.
a. The most important initial indicator of the severity of a head injury is the
patient's level of consciousness. A competent observer should assess the patient's
consciousness level as soon as possible after the injury has occurred. A severe head
injury may be defined as one that leaves the patient unconscious for at least 6 hours. A
patient who has an altered level of consciousness less severe and for a shorter time
period may have medical problems much later, problems caused by the injury.)
Therefore, a patient with any level of impaired consciousness after a head injury should
be treated as though he has a serious head injury.
b. The majority of head injuries are mild and self-limiting. However, since
severe head injuries can be life-threatening, it is important to assess and treat a head
injury correctly to prevent death or disability from secondary brain damage.
Pathophysiology is the physiology of disordered function. When there is trauma
to the central nervous system in the form of a head injury, a variety of
pathophysiological responses can occur.
a. Head Injury. The words "head injury" usually refer to an injury to the portion
of the skull (cranium) that encloses the brain, the overlying scalp, or the contents of the
cranial cavity (brain, cranial nerves, meninges, and associated blood vessels). This
definition focuses attention on that portion of the head that is at or above the level of the
eyebrows anteriorly, the zygomatic arches laterally, and an imaginary line between the
tips of the mastoid processes posteriorly. These are approximate external landmarks
for the skull base, which is the floor of the cranial cavity. Nevertheless, physical signs of