Lizard Bites

The exotic pet industry in the United States is growing rapidly, with an estimated 7.3 million pet reptiles owned by 3% of all U.S. households. Today, reptile trade is increasingly dominated by lizards. The most popular choice is the common green iguana (Iguana iguana). They can deliver significant injury with their teeth, claws, and tails (84).

The only venomous lizards in the world are found in North America. The Gila monster (Heloderma suspectum) is endemic to the southwestern United States, and the closely related Mexican beaded lizard (Heloderma horridum) is found along the west coast of Mexico. Although docile and sluggish, the Gila monster can suddenly become aggressive if handled (9,85,86).

Gila monsters may hang on during a bite, and mechanical means may be required to loosen the grip of the jaws. Bites of Gila monsters result in significant tissue trauma and even retention of fractured and avulsed teeth in tissue. The teeth of the Gila monster are sharp, recurved, poorly anchored, and periodically shed. Soft-tissue radiographs are unlikely to demonstrate retained teeth, so the wound must be explored for foreign bodies, after it is cleansed with a bactericide and irrigated copiously with normal saline (9,85-87).

Pain begins almost immediately, can be excruciating, peaks at 15 to 45 minutes, and is minimal at 6 to 10 hours. Local injections of lidocaine will relieve the intense pain. Bleeding from the wound may be profuse (9,85,86).

The venom delivery system is primitive (rigid teeth) and true envenoma-tions are rarely reported. The Gila monster is unique among lizards in having venom glands. All the teeth are grooved and venom flows by simple capillary action up these grooves. Venom flow is augmented by the chewing motions characteristic of Gila monsters once attached to the victim. The chewing bite potentially causes more envenomation than the slashing bite. Systemic complaints of nausea, diaphoresis, and dizziness last about 1 hour. Patients also have hypotension, tachycardia, and generalized weakness, nausea, and vomiting. No antivenin is available, but only one death was recorded from Gila bites during the period from 1929 to 1969 (9,85-87).

0 0

Post a comment