Week 1 lecture 1 Flashcards
(97 cards)
Dose response theory
only the dose makes something not a poision
venomous
poisons secretion w/ delivery system (it bites you)
poisonous
substance = injurious when taken internally or applied externally (you bite it)
Types of venomous snakes in the US
- mycotoxic
- neurotoxic
mycotoxic
- cause necrosis where bite
neurotoxic
disrupt ns can -> death
Crotalinae snake features
- mycotoxic
- hollow retractable fangs
- triangular head
- make up most snake bites in us
Types of Crotaline snakes
- Agkistrodon spp. (Southern Copper heads)
- Crotalus (rattlers)
Agkistrodon spp.
- Crotaline snake (mycotoxic)
- Southern copperheads and cottonmouth moccasins
- cause necrotizing bites, survive unless v small animal
- moccasins can bite under water*
Crotalus spp.
- Crotaline snake (mycotoxic)
- Rattler, cause majority of Crotaline snake deaths
Include: - timber rattlesnake (few in NY)
- eastern diamondback
- pygmy rattlesnake (south)
- Massasauga (rare in ny)
- Mojave (sw)
- Western diamondback (sw)
- Ridgenose (sw)
- Side winder (sw)
Crotalinine venom
- Low molecular weight polypeptide
- Metalloproteinases
- thrombin like glycoproteins, fibrinolysins
- digestive enzymes
- myotoxins
low molecular weight polypeptide fx venom
- capillary leakage, third spacing
- shock at high enough dose
metalloproteinases fx venom
hemorrhage and spreading factors
thrombin like glycoproteins fibrinolysis fx venom
- coagulopathy, thrombocytopenia, hypofibrinogenemia
digestive enzymes fx venom
- spreading factors
myotoxins fx venom
muscle necrosis
What factors contribute to effect of venom
- site, size, species of vicim
- behavior and motivation of snake (dry bite vs venomous bite)
- dead snakes bite
Crotalus envenomation signs
- localized signs hemorrhage and swelling
- systemic signs (muscle fasciculations, resp paralysis, severe hypotension or shock, venom induced coagulopathy, arrhythmia)
Respiratory distress crotalus envenomation
- head bites horses and camelids
Tissue ischemia and necrosis crotalus envenomation
- compartment syndrome
- uncommon in horses
Crotalus envenomation dogs
- face/ head bites
crotalus envenomation cats
- bites on front legs
crotalus envenomation ferrets
- bites to face
Crotalus envenomation horse
- bite on nose, legs