Lecture 8 Flashcards
Difference between venom and posion
Venomous animals actively inject toxins into victim
Poisonous animals secrete poisons passively
What are the three classes of venom compounds and what do they cause
Lmw substances- pain, inflammation, hypotension
Peptides- direct toxic effects and allergies
Enzymes- cause toxicity and allergy
What are the organisms in hymenoptera
Bees, wasps, hornets, fire ants
*envenomate with stinger, bees sting once, wasps and hornets sting repeatedly, worry about swarms
MOA of bee venom
50% melittin acts as a detergent and hemolytic, causes pain and histamine release
12% phospholipase destroys membranes
MOA of wasps/hornets
Some contain neurotoxins
Alarm pheromones alert the swarm to an intruder
Kinins produce pain
MOA of ant venom
Piperidine causes dermal necrosis
Formic acid causes burning sensation and pain
Both have cytotoxic, hemolytic, fungicidal, insecticidal, and bactericidal properties
Clinical signs of hymenoptera
Local swelling and reds at site of sting
Anaphylaxis (common cause of death)
Systemic toxicity from delayed allergic reaction (shock, hemolysis, rhabdomyolysis, hepatic and renal injury)
Treatment of hymenoptera
Remove stinger by scraping
Cold compress
Antihistamines and corticosteroids
Monitor for anaphylaxis
What toxin is produced by ticks and what is the MOA
Holocyclotoxin from salivary gland
Impairs acetycholine release at NMJ resulting in weakness and paralysis. May also act on Na channels
Clinical signs from tick
Appear 6-14 days after attachment of tick
Loss of appetite and voice, incoordination, ascending flaccid paralysis, excessive saliva and vomiting, resp distress, death from resp paralysis
How to diagnose ticks
Find dermacentor or ixodes ticks
Ascending paralysis and loss of voice
Treatment of ticks
Supportive care Atropine sulfate Anti emetics Fluids Oxygen
What poisonous toad are commonly lethal
B. Marinus (cane toad/ giant toad) in FL
B. Alvarius in arizona/ california
Eggs and tadpoles are also toxic
Toad MOA
Biogenic amines cause vasocontriction, hypotension, hallucination, GI effects
Bufogenins inhibit Na/K atpase like cardiac glycosides
Diagnosis of toad
Immediate hypersalivation and/or foaming at mouth, head shaking, vomiting Hyperemic gums Arrhythmias Neurologic signs Hyperkalemia Death can occur in as little as 15 min!
Treatment of toads
Oral decontamination with water lavage Activated charcoal Treat seizures and arrhythmias Fluids Treat neurologic signs/ hyperkalemia with digoxin
Describe black widow toxins
Has red hourglass on abdomen
Only females are toxic
Venom contains alpha-latrotoxin which creates pores in the membranes allowing Ca entry
Clinical signs of black widows
Muscle cramping and spasms Rapid weight loss Abdominal rigidity Restlessness, writhing Vocalization Hypertension Tachycardia, resp collapse
Who is most sensitive to black widow venom
Cats
Treatment of black widows
Control muscle spasms and pain
Calcium gluconate
Anti venom is the only proven treatment
Supportive care
Describe the brown recluse venom
Contain necrotizing enzymes like sphingomyelinase D
*dogs are most susceptible
Clinical signs of brown recluse
Inital bite causes little to no pain
3-8 hours after bite the site becomes red, swollen, tender, forms a bullseye
Hemolytic anemia, fever, weakness, leukocytosis
Treatment of brown recluse
Dapsone for dermal lesion
Fluids, anti inflammatorys, glucocorticoids
Analgesics
What families contain basically all the venomous snakes
Elapidae or crotalidae
Who are the most common victims of snake envenomation
Dogs and horses
What causes death with snake venom
Resp paralysis
Describe the eastern coral snake
Red, yellow, and black
Small fangs and small heads
Round pupils
MOA of coral snake
Venom has bungarotoxin (neurotoxin)
Prevent binding of acetylcholine causing paralysis
Clinical signs of coral snake envenomation
Local tissue necrosis
Hemolysis in dogs
Myoglobinemia in cats
Salivation, dyspnea, hyporeflexia, CNS depression, paralysis
Treatment of coral snakes
Administer anti venom if neurologic signs develop
Monitor resp signs
Antibiotics and symptomatic wound care
What are some examples of pit vipers
Copperhead, cottonmouth, rattlesnake
Clinical sign of pit vipers
Distinct fang marks Immediate swelling and bruising Hypotension, shock, tachycardia, tachypnea Anticoagulation Tissue necrosis
Treatment of snakes
Every case is different
Only proven therapy is anti venom
Why should you not cute, ice, or tourniquet a snake bite
Don’t localize the venom to one area
What are enterotoxins
Binds to intestinal epithelium, increases permeability and causes fluid loss and decreased absorption of nutrients
What are examples of enterotoxins
Salmonella, E coli, bacillus, strep, C. Perfringens
Clinical signs of enterotoxins
Vomiting, diarrhea, abdominal pain, stasis with gas accumulation and bowel distension
What is an endotoxin
Lipopolysaccharide from gram negative walls
What do endotoxins cause
Inflammatory processes and causes release of prostaglandins and histamine
Clinical signs of endotoxins
Circulatory collapse, pancreatitis, activation of clotting cascade, uncoupling of oxidative phosphorylation in the heart
Lethargy, fever, hypothermia, diarrhea, abdominal pain, shock bad smelling poop
Treatment of enterotoxins and endotoxins
Emesis
CV function
Correct fluid and electrolyte imbalances
Antibiotics
Where does botulism come from
Clostridium botulinum
What does botulism do
Prevents Ach release at NMJ causing paralysis
Clinical signs of botulism
Decreased tongue and tail tone
Dropping food from mouth, salivation
Weakness, weak vocalization, progressive paresis, bradycarida, constipation, urinary retention
What should you differentiate botulism from
Anticholinesterases. Ionophores, lead, nitrate
Treatment of botulism
Supportive therapy and IV fluids Resp support Oxygen therapy Warm water enemas and bladder expression Antibiotics Antitoxins as long it is not in neurons yet
