Pathophysiology

Crocodilians survived the Ice Age and are the dominant predators in many of the world’s tropical waterways. The American alligator may be found in the southeastern United States, from North Carolina to Louisiana. The saltwater crocodile is found in Southeast Asia and Australia, with males reaching lengths of up to 23 feet (7 m). Victims of crocodilian attacks sustain trauma from a combination of penetrating, blunt, and sheer force. The saltwater crocodile can generate 2000 psi when it bites. The sheer magnitude of the jaw muscle force sustained with extensive penetrating injuries devitalizes large areas of tissue, thereby making such injuries slow to heal and susceptible to infection. Bites must be considered to be heavily contaminated with multiple bacteria, including Aeromonas hydrophila, Pseudomonas, and Proteus (Fig. 141.1).

Fig. 141.1 Crocodile.

(Courtesy Hogle Zoo, Salt Lake City, UT.)

Presenting Signs and Symptoms

Crocodilian bites are characterized by punctures and tears. Their teeth are conical and not designed for chewing but for grasping their prey. Among survivors, the extremities were the most commonly injured site, with less than 10% sustaining torso trauma.^3,6 Crocodilians may also roll their entire body (known as the “death roll”) to disorient and drown the victim, as well as to tear pieces from the victim’s body.³ The force of the massive jaws may lead to extensive internal injury, but even when bite wounds are not present, the force of the animal’s movement—or even blunt trauma from its tail—may also inflict significant internal trauma. Initial survivors of severe attacks may exhibit hypotension from massive hemorrhage, in addition to respiratory distress from submersion injury.

Differential Diagnosis and Medical Decision Making

Victims of crocodilian bites often have injuries comparable with those sustained in a severe motor vehicle collision. Prehospital care should start with movement of the patient to a safe environment well away from water’s edge. The provider should make sure that airway control, breathing, and circulatory support are adequate with use of the advanced trauma life support (ATLS) protocols. External hemorrhage should be controlled with direct pressure or packing, and chest wounds should be dressed to prevent the development of tension physiology. Extremity fractures should be splinted and suspected major pelvic deformities bound or sheeted. Resuscitation in the hospital should continue according to ATLS protocols, including a focused assessment with sonography for trauma.

A secondary evaluation should be done to determine the extent of tendon, neurologic, and vascular injuries and possible internal organ damage. Underlying fractures and dislocations should be considered, particularly in light of the force and sheering mechanism of the animal’s bite. Depending on the nature and location of the bite, radiographs can aid in evaluation for bony injury. Computed tomography may be useful to evaluate for internal injury.

Treatment

Specialists should be consulted to evaluate and treat internal injuries, nerve and tendon damage, fractures, and major lacerations. Local wound care techniques are mandated to cleanse what are typically very contaminated wounds. Because of the high incidence of infection, all significant wounds need exploration, preferably in the operating room, where débridement of devitalized tissue and thorough decontamination can be accomplished. Prophylactic broad-spectrum antibiotic therapy may be necessary to prevent wound infection. The patient’s tetanus status should be checked and brought up to date.

Follow-Up, Next Steps in Care, and Patient Education

Disposition is based on the extent of the injuries, but admission should be considered for all patients except those with minor cutaneous extremity trauma. If the patient is discharged, close follow-up is advisable for wound care and to evaluate for wound infection. Prolonged rehabilitation is frequently needed because of the extent of injuries. The public should be advised to contact local wildlife managers about crocodilian activity before recreating in crocodilian-inhabited environments. Care should be taken when swimming, wading in, or approaching water. If attacked, the best defense appears to be to “fight back” by gouging the crocodile’s eyes with thumbs and fingers. If a hand or arm is within the reptile’s mouth, reaching caudally may displace the palatal valve, causing the crocodile to aspirate water and open its mouth.

Pathophysiology

The Gila monster (Heloderma suspectum) and the closely related beaded lizard (Heloderma horridum) are native to the southwestern United States and Mexico but may be found throughout the world in zoos and as illegal pets. They are characterized by black beadlike scales mixed with bandlike patterns of yellow, white, or pink scales (Fig. 141.2). These reptiles typically range in length from 9 to 32 inches (22 to 81 cm); the beaded lizard is the larger of the two species.

Fig. 141.2 Gila monster.

(Courtesy Hogle Zoo, Salt Lake City, UT.)

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