Envenomations from the Texas coral snake are often extremely painful. Objective findings may include ptosis, diplopia, dysphonia, dysphagia, salivation, and skeletal muscle weakness. 62 There are no cases of respiratory failure or skeletal muscle paralysis reported in the medical literature. A 1989 case report describes significant paresthesias as well as diplopia despite no erythema, swelling, or wound in a 27-year-old soldier bitten by a Texas coral snake during a training exercise. 67 Figure 9. Texas Coral Snake
the following were observed: Emesis (25%), weakness (15%), diplopia (10%), dyspnea (10%), and fasciculations (5%). 63 Patients should be monitored for at least 12–18 hours. Serial dynamometry, continuous end-tidal carbon dioxide monitoring, and serial negative inspiratory force measurements should be used to assess the patient in a manner similar to how they are used in the evaluation of a patient with a neurotoxic crotalids envenomation. Supportive care suffices for most coral snake envenomations. Analgesia is frequently necessary. As with crotalid envenomations, opioids and ketamine are both options. Because hematologic toxicity is not observed in coral snake envenomations, NSAIDs may also be used, although they may not provide sufficient pain relief. Transdermal lidocaine may be used as monotherapy or in conjunction with oral or parenteral analgesics. Endotracheal intubation and mechanical ventilation are necessary for patients with respiratory insufficiency. Because there is no significant swelling or tissue damage following coral snake envenomations, affected limbs should be positioned in whatever way the patient is most comfortable. Tetanus immunization should be updated as needed. Prophylactic antibiotics should not be administered. Antivenom is indicated for patients with any objective respiratory or skeletal muscle weakness. It is not necessary for local swelling, paresthesias, or pain. North American coral snake antivenom (NACSAV) was originally manufactured by Wyeth, which discontinued production in 2008. Pfizer acquired the company in 2009, and for several years, as the expiration dates for several lots were approaching, the FDA granted approval for an extension. NACSAV production resumed in 2019. Most hospitals do not keep it in stock, but supplies may be located using the Antivenom Index, which is administered by the Association of Zoos and Aquariums and the University of Arizona College of Pharmacy and to which poison control centers (PCCs) have access. In the rare instance when NACSAV is warranted but unavailable, there are some potential alternatives. Coralmyn is a Mexican product that has been recommended by PCCs. However, one study found that it did not effectively neutralize M. tener venom. The Costa Rican antivenom produced by the Instituto Clodomiro Picado is also indicated, but not FDA-approved, for North American coral snake envenomations. There is no role for the antivenoms approved for North American crotalid envenomation in patients with coral snake envenomations. toxicity simultaneously. Although most bites from species in the family Colubridae are clinically insignificant, several can be serious or even fatal. The boomslang ( Dispholidus typus ), for example, can cause severe coagulopathy resulting in exsanguination. A discussion of the pathophysiology, clinical features, and management of all of these nonnative envenomations is beyond the scope of this review. Healthcare professionals treating patients with these exotic envenomations are encouraged to contact their regional poison control center or snakebite expert for specific recommendations, including how to access the appropriate nonnative antivenom and what other pharmacologic interventions may be helpful.
Source: Nathan Wells The Eastern coral snake is responsible for the most significant toxicity from native coral snake envenomations. Death is exceptionally rare, but progressive neurologic signs and symptoms, including respiratory paralysis, may be observed. In a study of 387 patients with M. fulvius bites, 218 (56.3%) had no symptoms. Among symptomatic patients, the following were observed: Pain (40.6%), paresthesias (28.4%), emesis (11.4%), weakness (6.7%), respiratory depression (3.1%), and paralysis (2.8%). 64 Additionally, 2.8% of patients were intubated and placed on mechanical ventilation. In a study of 39 Eastern coral snake envenomations, in addition to swelling and paresthesias, which were reported in 40% and 35% of patients, respectively, Nonnative snake envenomations Of the 8,000–10,000 snake envenomations evaluated in U.S. EDs annually, fewer than 1% are due to nonnative snakes. 1-5 Exotic snakes that are most commonly implicated in bites include the monocled cobra ( Naja kaouthia ), African bush viper (A theris squamigera ), Gaboon vipers ( Bitis gabonica, B. rhinoceros ), and white-lipped tree viper ( Trimeresurus albolabris ). 68,69 A wide variety of exotic snakes, many of which are venomous, are maintained in zoos and private collections. Some of these snakes are vipers, and envenomations may resemble native crotalid envenomations. Some elapid envenomations are exclusively neurotoxic and present similarly to native coral snake envenomation. Other elapids can cause local and systemic
LIZARD BITES
The Gila monster, Heloderma suspectum , is the only venomous lizard that is native to the U.S. 70 There are two recognized subspecies. The banded Gila monster, H. s. cinctum, is found in western Arizona, eastern California, southern Utah, and southern Nevada. The reticulate Gila monster, H. s. suspectum, is confined to central and southern Arizona and western New Mexico. 70 Gila monsters can also be found in zoos and private collections, particularly in states with lax venomous animal ownership laws. Because Gila monster envenomations are relatively infrequent, the AAPCC does not provide specific data regarding these exposures in their annual reports.
The venom apparatus of Gila monsters is relatively rudimentary. Multilobed perimandibular glands produce venom that is transported through short ducts leading to backward facing grooved teeth in the lower jaw, and venom is introduced following a bite. 70,71 Because of their powerful jaws, Gila monsters often remain firmly attached to the victim. Gila monster venom contains a complex mixture of toxins. 71-75 Helodermin and helospectin are similar to vasoactive intestinal peptide. Exendin-4 increases insulin secretion and suppresses glucagon release. Helothermine causes pain and can lower body temperature and contribute to lethargy and paralysis
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