Tox Final Flashcards
Most common snake bites are from what group of snakes and in what type of animal?
pit vipers (crotalidae) - esp. copperheads dogs
Coral snake
- shy, non-aggressive, nocturnal
- short, fixed, mem covered fangs w/ venom dripping out
- delayed neurotoxic venom (little rxn at site) –> flaccid paralysis, resp paralysis
Coral snake bite treatment
- Hospitalize at least 24 hrs b/c tox signs can take 12 + hrs to develop
- supportive care, resp support, compression bandage, broad spec antibiotics
- antivenin treatment discontinued
Pit vipers (rattlesnakes and cottonmouth)
- retractable fangs + muscle cxn forces venom out
- defensive (dry) or agonal bite (whole load)
- venom meant to pre-digest, not kill
toxicity of rattle snake venom
rattle snake > water moccasin > copperhead
clin signs of diamondback bite
marked tissue destruction
coagulopathy
hypotension
clin signs of mojave A rattlesnake
minimal tissue destruction
no coagulation
severe neurotoxicosis
general clin signs of a pit viper bite (can be delayed)
regional swelling for ~36 hrs
ecchymosis & petechiation
+/- visible puncture wounds
tachycardia, shallow breathing, nausea, salivation, muscle twitch
treat a pit viper bite
baseline blood, recheck q6hrs to see level of evenomation
supportive care
Crofab antivenin - affects length of recovery, not survival chance
prognosis of pit viper bites
SA - good if early treatment
LA - survive initial bite, but often risk of dying w/ secondary tissue damage/infection
2 venomous lizards in US
Gila Monster
Mexican bearded lizard
venomous lizard bites
- defensive only, don’t inject venom must be chewed in
- longer bite duration = more evenomation
- pain at bite site, tooth lacerations, regional muscle fasiculations but tissue necrosis rare
treat a venomous lizard bite
supportive care
broad spec antibiotics
narcotics or fentanyl for pain managment
prognosis good
Black widow bites
- venom very potent (alpha-latrotoxin)
- causes lactrodectism (muscle tightness/pain first few hours –> weakness/fatigue, insomnia)
- cats very sensitive, get atonic paralysis & severe pain
treat a black widow bite
Lycovac antivenin
supportive - opiods, dizaepam (muscle rigidity)
(brown) recluse spider bite
- bullseye lesion, slow to heal (6 mo - 1 yr)
- venom has necrotizing enzymes, sphingomyleinase D
- systemic signs rare
- chemically debride lesion, drugs for pain, pruritis, infection, dapsone to inhibit neut migration
Are tarantulas dangerous?
US types - no
South America, Africa, Aus types - yes b/c neurotoxin (sometimes kept as illegal pets)
Scorpion sting (AZ bark scorpion)
- venom has multiple toxins
- sharp instant pain at site, edema, pruritis
- maybe allergic rxn, systemic rxn
- supportive care
- debated if evenomation concerning in dogs/cats or not
Tick paralysis
- 1 tick to infestation can cause
- MOA of toxin unknown
- ataxia –> paresis, flaccid paralysis –> resp failure, death
- remove tick!! supportive care, topical insecticides
Bee stings
- bronchiole constriction in cats
- anaphylactic shock, secondary IMHA in dogs
- remove stinger, supportive care, monitor for anaphylaxis
Botulism
- limber neck (Bird), shaker foal synd (EQ)
- ## Clostridum botulinum, multiple toxin types
Botulism MOA
toxin is protein, internalized by cell –> block ACh release –> progressive flaccid paralysis
3 ways to get botulism toxicity
- ingest preformed toxin (common in soil)
- Ingest spores (foals)
- wound contamination (e.g. castration)
Treat/prevent botulism
remove insiting cause (feed, debride) antitoxin, penicillin
prognosis guarded if have clin signs
prevent - toxoid vacc, good management
Tetanus MOA
- Clostridium tetani w/ tetanospamin neurotoxin in soil
- endocytosed into cells, block inhibitory NT release –> uncontrolled muscle contraction –> tetanty, sardonic grin, lock jaw, light sensitivity
- EQ, rum more susceptible than dogs, cats
treat/prevent tetanus
- penicillin, antitoxin tx, clean/debride wound
- quiet dark space, maybe tranquilize
- prognosis guarded w/ clin signgs
- prevention key - good husbandry/mgmt, tetanus vacc
Cyanobacteria (blue-green algae)
- risk factors: warm weather, increased nutrients (runoff) in water, algal blooms in late summer/early fall
- increased wind concentrating cyanobacteria
- often just see acute death
Microcystin or nodularin cyanobacteria toxicosis
hepatotoxic lethargic, vomiting, pale mucous mems, death in 24+ hrs
Anatoxin-a cyanobacteria toxicosis
muscle tremors, rigidity, resp distress/paralysis, convulsions, death in 30 min
Anatoxin-a(s) cyanobacteria toxicosis
SLUDGE, tremors, dyspnea, convulsions, death in 1 hr (resp arrest)
Treat cyanobacteria ingeston
Prevention is key - don’t eat
prognosis poor if have clinical signs, supportive care & decontaminate
atropine if anatoxin-a(s) - to blocK ACH while AChE blocked
Blister Beetles (aka Cantharidiasis)
- beetles crushed in alfalfa, horse eats, cantharidin toxin (vesicant) rapidly absorbed in GI and conc in urine
- acute colic, discomfort, bloody urine
- enhance elimination, control pain, fix dehydration/electrolytes
- prognosis poor, better if diagnosed early. Prevention!
Toad toxicity (FL, TX, AZ, CO, HI)
- dogs
- parotid glands on toad release toxin, absorbed in buccal mucosa
- toxin is cardiac glycoside –> inhibit Na/K/ATPase pumps –> decreased AP’s
clin signs & treatment of toad toxicity
- hypersalivation, vomiting –> convulsions, neuro –> coma, death w/in 15 mins sometimes
- decontaminate - rinse mouth, supportive care
- prognosis good if early decontaminate, don’t lick toads
Aflatoxins (from Aspergillus)
- found in corn, usually exposure by feed contamination
- metabolized into a reactive metabolite - carcinogenic, teratogenic, immunosuppressive
- chronic exposure = liver dz
- acute dose = emesis, diarrhea, convulsions, epistaxis, death
- prevention key, activated charcoal + oxytetracycline for hepatic damage - recovery prolonged/incomplete
Citrinin & Ochratoxin (aspergillus, penicllium spp)
- grains, beans, black pepper, coffee, etc.
- pigs and rats
- Porcine mycotoxin nephropathy
- enterohepatic recycling = longer half life, accums in kidneys
- chronic = kidney dz
- acute = gastroenteritis, emesis, tenesmus, etc
Why are ruminants relatively immune to ochratoxin toxicosis?
rumen microbes cleave the toxin into an non-toxic form
Ergot (Claviceps spp)
- grasses, cereal grains
- 5-HT(serotonin) agonist, Dopamine antagonist, NE agonist
- cause vasoconstriction
4 forms of Ergot toxicosis in livestock
- Cutaneous & gangrenous lesions (tail, extremities)
- Hyperthermia, production loss
- Repro failure (weak foals, stillborns)
- convulsive/neuro form (acute ingestion of large dose)
fescu foot
Trichothecenes (Fusarium spp)
- contaminated feeds during flowering, seed development (high rain, humidity) + delayed harvest
- most animals recover rapidly except pigs (highly sensitive, can’t metabolize vomitoxin –> vomiting)
Zearalenone (Fusarium spp)
- corn, stable in environ
- pigs, mebe sheep
- enz’s that produce acid are induced at low temps –> clin signs freq in colder areas
- enterohepatic recycling = increased half life
- acts as weak estrogen: swelling/redness of female parts, ovarian atrophy, weight gain
- remove contamination, PG F2- alpha can correct anestrus
Fumonisin
- ELEM (eq encephalomalacia) or PPE (porcine pulmonary edema)
- cattle resistant
- guidelines for max allowed in feed
- no treatment
ELEM clin signs
MOA not understood - cardio dysfunc
Neurotoxic and hepatic syndrome