in laboratory animals. Helodermatine and gilatoxin generate bradykinin, while Helokinestatins potentiate bradykinin receptors. There are also various phospolipases, hyaluronidase, proteases, and serotonin. Figure 10. Gila Monster (Heloderma Suspectum)
Coagulopathy, leukocytosis, acute renal failure, and hypokalemia are among the laboratory abnormalities that have been reported, although medically significant bleeding is not common. It is unclear if Gila monster venom is directly nephrotoxic or if renal failure results from hypoperfusion. Treatment of Heloderma envenomation is supportive; no antivenom exists. It may be necessary to separate the lizard from the patient. Oftentimes, just placing the lizard on the ground will encourage it to let go and escape. If the lizard remains attached, it will have to be removed. This can be accomplished by placing two long sticks or similarly shaped tools deep into the Gila monster’s mouth and prying it open. There is anecdotal evidence that pouring water or ethanol into the lizard’s mouth is also effective. Bare hands should not be used, as this can result in additional victims. Much of the local wound care is similar to snakebite management. Bites should not be incised. Tourniquets and pressure immobilization should be avoided. There is no role for electrical therapy. Extraction devices are ineffective and may be harmful. Proper wound care includes irrigation, foreign body removal, and debridement of devitalized tissue. Tetanus immunization should be updated as needed. The necessity of antibiotics has been debated. Analgesia should be provided. Intravenous opioids are frequently required. There may also be a role for subdissociative ketamine, particularly in patients with hypotension. Aggressive airway management is essential in patients with angioedema. Intravenous fluid resuscitation is the initial intervention for hypotension, but vasopressors, for example, epinephrine or norepinephrine, may be required. The bradykinin antagonist icatibant and the kallikrein antagonist ecallantide, and mast cell chymase have been used with varying degrees of success. 80 Fresh frozen plasma, C1 inhibitor concentrate, corticosteroids, and antihistamines have also been used to treat angioedema. Questions 1. Do we know what snake species is responsible for her symptoms? How important is it to determine the exact species? 2. What diagnostic studies should be ordered? 3. What treatments should be implemented at this time? 4. What are the indications for antivenom? Discussion 1. The patient’s history and physical examination are consistent with a pit viper, or crotalid, envenomation. In the U.S., 98% of venomous snake bites are due to various pit vipers, which include copperheads, cottonmouth, and rattlesnakes. Significant swelling, tenderness, and bruising will be seen in > 95% of native crotalid envenomations. Hematologic and systemic toxicity are observed less commonly. Although rattlesnake bites tend to be more severe than copperhead and cottonmouths on average, any pit viper envenomation can be mild, moderate, or severe. Because the clinical features of crotalid are similar, and because the two antivenoms that are FDA-approved for North American pit viper envenomations can be used for any native crotalid envenomation, it is not necessary to make an exact snake identification. Envenomations from coral snakes, which account for 2% of native venomous snakebites, are characterized by pain and/or paresthesias. Minimal swelling and erythema may be present, but the significant swelling and bruising characteristic of crotalid envenomations are not observed. Hematologic laboratory abnormalities are also not seen in coral snake envenomations. It should be very straightforward to clinically distinguish crotalid and coral snake envenomations.
Source: Chris Nguyen Clinical manifestations of Gila monster envenomation can be local and systemic. Patients report severe pain throughout the envenomed limb. 75-79 Swelling may be significant and associated with erythema and regional lymphadenitis. Tissue at the wound edges may be devitalized. Hypotension, tachycardia, and angioedema are common and appear rapidly. Patients may have weakness, dyspnea, pallor, abdominal pain, nausea, and vomiting. Diarrhea may be significant and prolonged. Case study 1: Snakebite Ms. Wyatt is A 24-year-old female who presents with left foot pain and swelling after being bitten by a snake. She reports that she was walking outside in the dark while wearing flip-flops. She saw a snake bite her on the lateral aspect of the foot. She did not recognize the snake and was unable to photograph it. Since incurring the bite, her foot has become increasingly painful. She has also had some nausea without vomiting. She denies dyspnea. Her vital signs: BP 120/80, HR 82, R 16, T 98.2, 99% O2 On examination, her left foot is swollen and tender. There is ecchymosis surrounding a single puncture wound to the lateral aspect of her left foot. There is no erythema. The remainder of her examination is unremarkable. Figure 11. Snakebite
Source: Spencer Greene
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Book Code: RPTTX2024
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