Zootoxins- Toad Toxin And Snake Venom Flashcards
What toxins does the Bufo toad carry?
Catecholamines Bufotenine Bufagenisn Bufotoxins Indole alkylamines
What are the toads in the Bufo family?
Cane or marine toad
Colorado river toad
What toxin from toads is a Schedule I substance because it has an hallucinogenic effect?
Bufotenine
Indole alkylamines are similar to the hallucinogen LSD
What species are most suspecptible to Bufo toad intoxication?
Dogs
Cats and ferrets can also be poisoned
Where are Bufo toxins absorbed?
Mucous membranes of mouth, gastric mucosa, conjunctiva, and open skin wounds
What is the MOA of Bufo toad intoxication?
Direct irritation of mucus membranes
Main organs affected -> heart, blood vessesl, and CNS
Bufotenine and bufotoxins ->digitalis-like effect by inhibiting Na/K ATPase
Indole alkylamines -> hallucinogenic
Bufotenine —> vasoconstriction and hallucinogenic
What are the clinical signs associated with Bufo toad intoxication?
Irritation of oral mucosa - hypersalivation (foaming), brick red mucous membrane, vocalization and vomiting
Neuro- disorientation, ataxia, circling, seizures, opisthotonos, hyperthermia, and coma
CV- tachypnea, tachycardia, cardiac arrhythmia, or bradycardia, and collapse
Increase in hemoglobin content, PCV, blood glucose, BUN, alkaline phosphatase, serum potassium, calcium, and phos
.. are consistent with what zootoxin?
Bufo toad toxin
What is the DDX for bufo toad intoxication?
Disease causing seizure, cardiac toxicity, caustic, and hyperthermia
DDX for diseases/toxins causing seizures?
Bufo toad toxin Metaldehyde Theobromine Cholinesterase inhibitor Idiopathic epilepsy Infectious meningioencephalitis
What toxins can cause cardiac toxcity?
Bufo toxin
Digitalis toxicity
Poisonous plant with cardiac glycosides (gossypol or oleander)
DDX for toxins that are caustic?
Bufo toxin
Acids/alkalis
Detergents
Bleaches
What is the treatment for bufo intoxication?
Flush mouth with water
Activated charcoal
Seizure -diazepam, phenobarbital, propofol, glucocorticoid, furosemide, and mannitol
Atropine for bradycardia, as bronchodilator, and decrease secretions (contraindicated with tachycardia)
Tachycardia/arrhythmia - B blocker/lidocaine/procainamide
Digoxin bay bind bufagenins and bufotoxins
Supportive therapy
What are the poisonous snakes of North America?
Pit vipers, Crotalid family
Coral snakes
What are the pit vipers snakes?
Rattlesnake
Copperhead
Cottonmouth
What are the general characteristics of pit viper snakes?
Have temp sensitive pit between eyes and nostrils
Head is broad and triangular
Pupils are vertical with prominent ellipitical slits
Retractable fangs of upper jaw
What toxins are in snake venom?
Enzymatic and nonenzymtic proteins and amino acids
Nonenzymatic proteins and peptides are “killing fraction”
What species is most susceptible to snake venom? Which is most sensitive?
Dogs are most susceptible but cats and horses also
Dogs are most sensitive
Of the pit vipers, which are the most toxic?
Rattlesnake > cottonmouth > copperhead
What is the MOA of snake venom?
PRIMARY effect is hypocoagulation
Hyalurondiase cause venom to spread
Phospholipase A2 disrupt cell membrane, and uncouples oxidative phosphorylation, and release vasoactive amines
Enzymatic and nonenzymatic proteins have hematoxic (procoagulant, anticoagulant ), cardiotoxic and neurotoxic effects
What are the clinical signs of pit viper envenomation?
Puncute worund, fang mark
Bleeding, edema, swelling, ecchymosis, petechia, and necrosis.
Lab shows echinocytosis, hemolysis, hemoconcentraiton, increased coagulation time
Hypokalemia, liver and renal failure
What zootoxin is this consistent with?
Pit viper envenomation
Treatment for snake envenomation?
First aid - keep calm, keep bite below level of heart, monitor swelling
Polyvalent crotalid antivenin - available for dogs, can cause allergic reaction (antiphylactoid therapy)
Diphenhydramine IV to reduce allergic rxn to antivenin and sedate
Fluid therapy
Blood transfusion
Broad-spectrum antibiotics
Control pain with fentanyl
Maintain airway and treat shock
T/F: if your dog gets a snake bite but has the rattle snake vaccine, you do not need to bring it in to be treated
False
Still considered an medial emergency
What are the characteristics of coral snakes?
Black head with alternating bands of black, yellow (or white) and red
Small head with rounded pupils
Short fixed front fangs
Require chewing action to inject venom
What is the MOA of coral snake envenomation ?
Local tissue rxn and destruction by hyaluronidase, proteinase, ribonuclease, desoxyribonuclease, and phospholipase
Primary effect is neurotoxic
Nondepolarizing neuromuscular blockade, CNS depression, muscle paralysis, and vasomotor activity
Hemolysis with severe anemia and hemoglobinuria reported in dog
Clinical signs with coral snake envenomation ?
CNS depression, quadriplegia with decreased spinal reflexes, respiratory paralysis, hypotension, and ventricular tachycardia
Dogs also can have hemolysis, anemia, hemoglobinuria, and may salivate excessively (not seen in cat)
Aspiration pneumonia can be a complication
Elevated fibrinogen and CK
RBC morphological changes, anemia, and hemoglobinuria
What zootoxin is this associated with?
Coral snake envenomation
What is your dddx for coral snake envenomation ?
Tick paralysis
Botulism
Myasthenia gravis
Treatment for coral snake envenomation ?
Micrurus fulvius antivenin
Life support and symptomatic therapy as in pit vipers
