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Flashcards in Envenomation Deck (22)
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1
Q

Pit vipers species (Crotalidae)

A

rattlesnakes (crotalus horridus)
copperheads (agkistrodon contortix)
cottonmouths, water moccasins (agkistrodon piscivorus)

2
Q

Where do pit vipers get their name?

A

temperature sensitive pit between eyes and nostrils

3
Q

How do pit vipers look?

A

head is broad and triangular
pupils are vertical prominent elliptical slits
retractable fangs in upper jaws
temperature sensitive pits between eyes and the nostrils

4
Q

Pit viper toxins

A

venoms are combination of enzymatic and non-enzymatic proteins and amino acids
non-enzymatic proteins and peptides are called killing fraction

5
Q

Most pit viper bites are due to

A

copperheads

6
Q

Toxicity of pit viper bites

A

dogs are most susceptible but cats and horses are also susceptible
dogs are more sensitive but cats usually severely affected

7
Q

Rank the pit vipers from most to least toxic

A

rattlesnakes > cottonmouths>copperheads

8
Q

MoA of pit viper venom

A

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

9
Q

Primary effect of pit viper venom is

A

hypercoagulation

10
Q

Clinical signs of pit viper enenomation

A

local tissue reactions include puncture wounds, fang marks, bleeding, edema, swelling, ecchymosis, petechiation, necrosis

11
Q

Diagnosis of pit vipers

A

hematological changes - echinocytosis, hemolysis, hemoconcentration, increased or decreased coat time, DIC
chem changes - hypokalemia, hyperkalemia, liver and renal failure

12
Q

Treatment of pit venom envenomation

A

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

13
Q

T/F: there is a rattlesnake vaccination for dogs

A

true

14
Q

Coral snakes species

A

Sonoran coral snake (Micruroides euryxanthus)
eastern coral snake (micrurus fulvius fulvius)
texas coral snake (micrurus fulvius tenere)
south Florida coral snake (micrurus fulvius barbouri)

15
Q

Characteristics of coral snakes

A

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

16
Q

Toxicity of coral snake bites

A

bites are rare, 60% are nonenvenomating

17
Q

MoA of coral snake envenomation

A

local tissue reaction is little
tissue destruction caused by hyaluronidase, proteinase, ribonuclease, deoxyribonuclease, phospholipase
nondepolarzing neuromuscular blockade, CNS depression, muscle paralysis, vasomotor instability
hemolysis with severe anemia and hemoglobinuria have also been reported in dogs

18
Q

primary effect of coral snake envenomation

A

neurotoxicity

19
Q

Clinical signs of coral snake envenomation

A

puncture wounds
CNS depression, quadriplegia with decreased spinal reflexes, resp paralysis, hypotension and ventricular tachycardia
dogs show intravascular hemolysis, anemia, hemoglobinuria and may vomit and salivate excessively
Cats - do not show hemolysis anemia and hemoglobinuria
aspiration pneumonia is important complication

20
Q

Lab diagnosis of coral snake envenomation

A

elevation of fibrinogen and creatine kinase

RBC morphological changes, anemia, and hemoglobinuria in dogs

21
Q

Aspiration pneumonia is a common complication of

A

coral snake envenomation

22
Q

Treatment of coral snake envenomation

A

specific micrurus fulvius antivenin

life support and symptomatic treatment