HEAD AND NECK INJURIES - Medicine for Mountaineering and Other Wilderness Activities - page 98

CHAPTER 8
HEAD AND NECK INJURIES
Philip F. Stahel, M.D.
Christoph E. Heyde, M.D.
Michael A. Flierl, M.D.
James A. Wilkerson, M.D.
Principal Contributors
Head injuries are the major potential cause of death in wilderness accidents. The most com-
mon causes are a fall from a height or a direct blow on the head from a falling object.
BRAIN INJURIES
Although most head injuries are of minor nature and do not require specific treatment, the
early identification of those individuals who have sustained a potentially significant brain
injury is of utmost importance. Airway protection and immediate evacuation are the crucial
treatments for a significant head injury in the wilderness.
Types of Brain Injuries
Most individuals who sustain a brain injury suffer a mild cerebral concussion, which is a
diffuse brain injury with preserved consciousness but a certain amount of temporary neur-
ologic dysfunction. In contrast, the classic cerebral concussion results in a reversible loss
of consciousness, which is always accompanied by a certain degree of a memory loss (am-
nesia). Approximately 3 to 10 percent of all individuals with a mild head injury (cerebral
concussion) develop potentially lethal bleeding inside the skull.
Localizedbraininjuryiscausedbydirectconcussionorcompressionforces,whereasdif-
fuseinjuriesareusuallycausedbyindirecttraumamechanisms,suchassuddendeceleration
or rotational acceleration. The most severe brain injuries are the so-called diffuse axonal in-
juries or focal contusions with bleeding inside or around the brain. Secondary brain injury
occurs after the initial trauma as a consequence of bleeding inside the skull and swelling of
the injured brain.
Amongthebrain'suniquefeaturesisitssnuglyfittingenvelopeofbone(theskull),which
is lined by a dense fibrous membrane (the dura). Although the skull is essential for protect-
ing the soft brain from injury, its presence may occasionally be a disadvantage. Bleeding or
swelling, which accompany injuries to any tissue, compress the brain within the rigid bony
covering and frequently produce damage and dysfunction far out of proportion to the ori-
ginal injury. A hemorrhage that would be of no significance at another site can cause death
when confined within the skull. Occasionally a blow to the head, although not severely in-
juringthebrainatthetime,tearssomeofthebloodvesselsaroundthebrain.Bloodfromthe
torn vessels pours into the narrow space between the brain and the skull and produces a clot