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Clinical Summary

The Gila monster (Heloderma suspectum) is a venomous lizard found in the southwestern United States and northwestern Mexico. The only other venomous lizard in the Americas is the Mexican beaded lizard, found from Mexico to Guatemala. Both species are unlikely to bite unless provoked. They secrete venom into their saliva and increase saliva production when they are agitated. When biting their victim, the Gila monster chews rather than injecting, is known to hang on vigorously, and often must be forced to release its powerful grasp. Teeth may break off and contaminate wounds. Like snake venoms, Gila monster and beaded lizard venoms are complex mixtures of proteolytic enzymes and vasoactive substances. The bite may cause pain with local edema and proximal radiation. Tachycardia and hypotension may occur, along with anaphylactic reactions. Systemic complaints may include generalized weakness, nausea and vomiting, diaphoresis, and paresthesias.

Management and Disposition

If not already separated from the victim in the prehospital phase, the lizard must be removed. Putting the lizard under running hot water or prying the jaws apart using an appropriate tool are two options. Caregivers should take precautions against being bitten themselves and should also take care to ensure the victim is not bitten again in the removal process. Hypotension can be treated with volume resuscitation. Anaphylaxis should be treated with epinephrine. There is no antivenom. Wound care should include copious irrigation and debridement as needed. Imaging should be used to rule out retained teeth. Tetanus prophylaxis is indicated. Prophylactic antibiotics are generally unnecessary. If the victim has no systemic symptoms several hours after observation, discharge with return precautions is appropriate. Patients with systemic symptoms should be admitted.

FIGURE 16.57

Reticulate Gila Monster. The Gila monster (Heloderma suspectum) is one of two venomous lizards found in the Americas. Its range is the southwestern United States and northwestern Mexico. (Photo contributor: Jeff Servoss, US Fish and Wildlife Service.)

FIGURE 16.58

Gila Monster Bite. Gila monster bites may be extremely painful. They usually do not cause severe tissue damage. Retained teeth are a hazard. (Photo contributor: John Sakles, MD.)

FIGURE 16.59

Gila Monster Bite, Tongue Swelling. Gila monster bites may cause anaphylactic reactions. (Photo contributor: John Sakles, MD.)

Pearls

  1. Gila monsters and Mexican beaded lizards have very powerful jaws. Forcible removal is often necessary and must be carefully undertaken to avoid further bites.

  2. Patients with systemic symptoms should be admitted, because progression to anaphylactic reactions is possible.

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