Most victims are attacked by single sharks, violently and without warning. In the majority of attacks
the victim does not see the shark before the attack. The first contact may be a bumping, which is an attempt
by the shark to wound the victim before the definitive strike. Severe skin abrasions from the shark skin
(shagreen) placoid scales (denticles) are produced in this manner. These microscopic appendages have the
same origin as teeth, with a pulp cavity, dentine, and vitreodentine ("enamel") covering.
The jaws of the major carnivorous sharks are crescent-shaped and contain up to five or six rows or
series of razor-sharp ripsaw triangular teeth, which are replaced every few weeks by advancing inner rows.
Each species has distinctively shaped teeth. However, a study of the teeth of the great white shark revealed no
consistent pattern of size or arrangement of the marginal serrations that was sufficiently characteristic within
an individual shark to serve as a reliable index of identification of a tooth as originating from that particular
shark. However, the serrations are sufficiently distinctive to enable the potential identification of an individual
tooth as having been the cause of a particular bitemark. While normal tooth replacement takes 7 to 10 days, in
some species a lost tooth can be replaced within 24 hours. Amazingly, some sharks produce up to 25,000 teeth
in a lifetime. The upper jaws generally have larger cutting teeth, while the sharp lower teeth are designed to
fasten onto and hold prey during capture. The teeth are cartilaginous, strengthened by the deposition of
calcium phosphate crystals (apatite) in a protein matrix, all covered by an enameloid substance. They are
considered to be as hard as granite and as strong as steel. In a great white shark the largest serrated triangular
teeth can grow to 2.5 inches. There are 26 upper and 24 lower teeth exposed in the front row. The height of
the enamel of the largest tooth in the upper jaw is proportional to the animal's length, so a body length of up
to 25 feet may be possible. The upper jaw is advanced forward and protruded to allow its participation in the
biting action. The biting force of some sharks is estimated at 18 tons per square inch. Severe shark bites result
acutely in massive tissue loss, hemorrhage, shock, and death. Even a smaller animal, such as a lemon shark,
can bite with bone-crushing force. The potential for destruction is unparalleled in the animal kingdom.
The human leg (or legs) is most frequently bitten, followed by the hands and arms, as the victim
attempts to fend off the shark. Proximal femoral artery disruption carries a poor prognosis because of the
torrential hemorrhage. While fractures are not common, broken ribs are often accompanied by intrathoracic,
intraperitoneal, and retroperitoneal injuries. Because the victim is generally far from medical assistance, blood
loss may be profound. The wounds have historically been fatal in 15% to 25% of attacks, with major causes of
death listed as hemorrhage and drowning. Rapid response and prehospital care seem to be somewhat
improving this statistic.
In most cases the immediate threat to life is hypovolemic shock. Thus it is occasionally necessary to
compress wounds or manually to constrict arterial bleeding while the victim is in the water. As soon as the
victim is out of the water, all means available must be used to ligate large, disrupted arteries or to apply
compression dressings. If possible the injudicious use of pressure points or tourniquets should be avoided. If
intravascular volume must be replaced in large quantities, at least two large-bore IV lines should be inserted
into the uninvolved extremities to deliver crystalloid (lactated Ringer s solution, normal saline, or hypertonic
saline), colloid, or blood products. Central venous cannulation should be reserved for the emergency
department.
The patient should be kept well oxygenated and warm while being transported to a facility equipped to
handle major trauma. Blood losses should be replaced with whole blood or packed red blood cells and fresh-
frozen plasma.
The precise ratio of crystalloid to blood products and proper mean arterial blood pressure
endpoint of primary resuscitation in the presence of a major vascular injury are the subjects of ongoing
investigations. The victim should be thoroughly examined for evidence of cervical, intrathoracic, and
intraabdominal injuries. Because Clostridium can be cultured from ocean water, tetanus toxoid 0.5 ml
intramuscularly (IM) and tetanus immune globulin (Hyper-Tet, Cutter) 250 to 500 units IM must be given.
The administration of prophylactic antibiotics is more controversial. We recommend that the victim of a shark
bite be treated
with an IV third-generation cephalosporin, trimethoprim-sulfamethoxazole, an aminoglycoside, ciprofloxacin,
or some reasonable combination of these agents. Imipenem-cilastatin should be reserved for established
wound infections or early indications of septicemia, particularly in the setting of immunosuppression. The
rationale for prophylactic antibiotics is that shark wounds are prone to heavy contamination with seawater,
