Envenomation Flashcards
Pit vipers species (Crotalidae)
rattlesnakes (crotalus horridus)
copperheads (agkistrodon contortix)
cottonmouths, water moccasins (agkistrodon piscivorus)
Where do pit vipers get their name?
temperature sensitive pit between eyes and nostrils
How do pit vipers look?
head is broad and triangular
pupils are vertical prominent elliptical slits
retractable fangs in upper jaws
temperature sensitive pits between eyes and the nostrils
Pit viper toxins
venoms are combination of enzymatic and non-enzymatic proteins and amino acids
non-enzymatic proteins and peptides are called killing fraction
Most pit viper bites are due to
copperheads
Toxicity of pit viper bites
dogs are most susceptible but cats and horses are also susceptible
dogs are more sensitive but cats usually severely affected
Rank the pit vipers from most to least toxic
rattlesnakes > cottonmouths>copperheads
MoA of pit viper venom
hyaluronidase causes venom to spread
phospholipase A2 disrupts cell membranes, uncouples phosphorylation and releases vasoactive amines
enzymatic and nonenzymatic proteins have hemotoxic (procoagulant, anticoagulant), cardiotoxic, and neurotoxic effects
Primary effect of pit viper venom is
hypercoagulation
Clinical signs of pit viper enenomation
local tissue reactions include puncture wounds, fang marks, bleeding, edema, swelling, ecchymosis, petechiation, necrosis
Diagnosis of pit vipers
hematological changes - echinocytosis, hemolysis, hemoconcentration, increased or decreased coat time, DIC
chem changes - hypokalemia, hyperkalemia, liver and renal failure
Treatment of pit venom envenomation
first aid measures - keep bite below heart level, hospitalize asap, avoid incision and suction of bite site to decrease venom absorption
polyvalent crotalid antivenin - may cause allergic reaction, anaphylactoid reactions treated with epinephrine, corticosteroids and fluid therapy
diphenhydramine IV or SC to reduce reactions to antivenin and as sedative
fluid therapy, blood transfusion, broad spectrum antibiotics
control pain by continuous IV infusion of fentanyl (avoid morphine)
corticosteroids, NSAIDs such as aspirin not recommended
T/F: there is a rattlesnake vaccination for dogs
true
Coral snakes species
Sonoran coral snake (Micruroides euryxanthus)
eastern coral snake (micrurus fulvius fulvius)
texas coral snake (micrurus fulvius tenere)
south Florida coral snake (micrurus fulvius barbouri)
Characteristics of coral snakes
small, non aggressive, nocturnal, not toxic
black head with alternating bands of black, yellow (or white), red
small head (not triangular) with round pupils
short, fixed front fangs
