Week 1 lecture 1 Flashcards
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
crotalus envenomation cattle
- bites on nose or tongue
crotalus envenomation camelids
- bites to head
Crotalus snake bite tx
- immediate transport to clinic, hospitalize (observe), find bite, assess every 4hrs, neutralize venom, wound management
- keep animal quiet
- cause minimal stress
- Benadryl
Crotalus snake bite contraindicated tx
- ice
- constriction bandages/ tourniques (inc likelihood of compartment syndrome)
- incision/ suction
- topical DMSO
- corticosteroids
analytic findings crotalus snake bite
- serum chem, cbc, coag every 4h (thrombocytopenia, anemia, neutrophillia, elevated CK, hypokalemia, hypocalcemia, elevated troponin in horses)
- hemoglobinuria
- Vic
VIC
- venom induced coagulopathy
Supportive care crotalus snake bite
- fluid therapy
- airway support
- heart rate and blood pressure monitoring
antivenin
- expensive and has foreign proteins
- allergic rxns (anaphylaxis possible) possible bc antibodies from diff species
- helpful if you can get it but hard to get access to it bc not a lot made bc $
who to call for antivenin
- Miami dade venom response
- poison control
- hospital or zoo
antivenin dosing
- based on venom amount not patient size
symptomatic care crotalus snake bite
- pain responses to antivenin
- fentanyl for refractory pain
- avoid morphine and NSAIDs
wound management crotalus snake bite
- keep wound clean and open
- antibiotics after you have culture back
long term care crotalus snake bite dogs
- hospitalize >8hrs observe >24 hrs
- dogs should improve < 2 days
- VIC can be refractory
long term care crotalus snake bite horse
- hospitalize >8hrs observe >24 hrs
- mortality in horses possible 5-7 days (myopathy, hepatopathy, resp failure, laminitis)
- VIC can be refractory
Elapidae
= closest things we have to cobras in Us
- coral snakes down south
- dont inject venom have to chew
- fixed fangs, round pupils, diurnal, red yellow and black bands
- neurotoxic
coral snake vs king snake
- red on black venom lack
- red on yellow kills the fellow
Sonoran coral snake
- mouth so tiny can’t bite anything bigger than a mouse
- v shy and v rarely encountered
elapidae snake venom components
- alpha- neurotoxins
- phospholipase A2
- myotoxins
alpha-neurotoxins clinical effects
- neurological effects
phospholipase A2 clinical effects
- soft tissue injury
myotoxins clinical effects
muscle necrosis
clinical signs coral snake envenomation
- small hard to find bites, snake may hang on in which case can find bite
- neurotic effect can be immediate but tend ot be delayed
- death
cause of death coral snake envenomation
- resp collapse
- circulatory collapse
clinical signs coral snake envenomation cats
- nicotinic effects when start off -> flacid paralysis
- weakness and muscle fasciculations
- ascending flaccid paralysis (resp depression and paralysis)
- CNS depression, anisocoria
- hypotension
- myoglobinuria
- hypothermia
Clinical signs of coral snake envenomation in dogs
- CNS depression
- Emesis
- Hyporeflexia
- Hypotension
- Hemolysis
- Resp depression
Coral snake bite tx
- hospitalized monitoring
- Baseline blood work (elevated CK, anemia w/ red cell changes)
- Long T1/2 of venom
- Stabilize
- Antigenin early
- wound management if needed
- respiratory support
- neuromuscular dysfunction
Prognosis for Elapid envenomation
- good w/ early aggressive tx, cats usually die
- can have prolonged recovery (cats)
venomous lizards
- Gila monster and Mexican beaded lizard
- Chewers with mycotoxic venom
- not aggressive will bite if you deserve it
Tropical toad
- poisons not venomous
- toxicosis from licking or chewing frog
Sonoran toad
- people lick these for hallucinations but heart can end up stopping
toxic principle of toad venom
- parotid gland secretions
- Bufodienolides (digitalis-like steroids)
clinical signs of toad poisioning
- dogs most commonly affected (drool alot)
- vocalization, anxiety, inc resp rate, neurologic
- death possible w/ in 15 min (can stop heart)
- severity of clinical signs varies
tx toad poisoning
- if dog still conscious oral lavage
- if seizing tx seizures
- cardiac support
- digibind = antidote for digitoxin but VERY expensive
spiders
- recluse spiders = myotoxic
- widow spiders= neurotoxic
brown recluse
- aka loxosceles
- southern US and midwest
- myotoxic
- most likely to find venomous spiders in produce section of grocery store
- bite when disturbed
recluse venom includes
- spreading factors
- hemolytic factors
- myelonecrotic factors
local signs loxosceles bite
- target lesions grow and lister
- 12-96 hrs see necrosis
systemic signs of loxosceles bite
- uncommon but can include:
- hemolysis
- dic
- death rare
avoid misdiagnosis sider bites
NOT RECULSE N- numerous lesions O- occurence T- timing (out of season) R- red center (should be ischemic) E- elevated (should be flat or sunken) C- chronic (should heal in < 3 mon) L- large (necrosis >10cm then probs something else) U- ulcerated in < 7 days S- swollen (except on face) E- exudative
tx loxosceles bite
- wound managements
- antibiotics PRN (La200 inhibits metalloprotineases)
- negative pressure wound therapy
- no antivenin in US
Widow spider
- lacrodectus spp.
- usually black can be red; usually black with red hourglass or spots
- males too small to bite only females bite
- bite if disturbed when hiding or if eggs = threatened
- one bite can = fatal (warmer climates -> more potent venom)
latrodectus venom
- widow spider
- neurotoxic, acts at neuromuscular junctions, is paralyzing (-> neurotransmitter release of Each, catecholamine, GABA, glutamate, inhibits ACh reuptake)
- inc nerve potential then -> dec nerve potential
local signs latrodectus bite
- cramping and pain near bite
- minimal swelling
- signs generally systemic
systemic signs latrodectism affect who
- cats and horses and camelids senstive
systemic signs latrodectism
- muscle cramps
- abd pain and rigidity
- hypertension and tachycardia
- ascending flaccid paralysis (death bc resp failure)
lactrodectism in cats
- early paralysis
- severe pain
- cheyne-stokes resp pattern (rapid shallow breathing then apnea)
- often die
supportive care lacrodecitsm
- cats need antivenin (die w/o it)
- other animals may survive with just supportive care
- min 48hr hosp
- cardio and resp monitoring (support)
- pain management and spasm control (opioids and diazepam)
antivenin lacrodectism (widow)
- equine origin, use in high risk patients (cats)
lacrodectism prognosis
- cats respond with antivenin but w/o it die
- signs begin to resolve in 48-72 hrs (some signs persist for months)
scorpion poisoning tx
- usually symptomatic tx and analgesia
- see tremors and cns stim
tick paralysis
- rare in US usually see in australia
- female tick secretes venom that -> paralysis
- if have paralysis of unk origin especially ascending paralysis consider this as cause
- once take tick off recover like magic (use acaricides to make sure all ticks off if no contraindications)
tick paralysis signs
- ascending paresis (2-9 days after attachment), begins at pelvic limbs
- resp paralysis in cats
- facial paresis/ paralysis
- remain bright and alert
Hymenoptera spp.
- bees, wasps, hornets
- local rxn can -> resp obstruction
- hypersenstivitis (some breeds)
Apoidea
- bees
- barbed signer remains in vicrim
- docile, but africanized bees are aggressive and will swarm can -> death if enough bees stinging
Vespidea
- wasps, hornets
- agressive, sting mult times
Clinical signs bee and wasp sting
- immediate pain
- local pain/ swelling
- skin sloughing in cattle
- systemic response to mult stings in dogs (African bees) shock, DIC, hemorrhage
- hepatic damage dogs and cats
- bronchoconstriction cats
- rhabdomyolysis and hemolysis horse
- anaphylaxis
bee and wasp sting tx
- scrape stinger away, avoid pinching
- tx for anphylasix as needed
solenopsis spp.
- fire ants
- all sting at once w/ formic acid -> pustules
- can kill small animals
- livestock death possible e
fire ant venom
- 95% alkaloids
clinical signs fire ants dogs
- no pustules
- erythematous papules usually resolve <24 hrs
- occasional systemic signs (rhabdomyolysis, DIC, seizures)
tx fire ant stings
- sytmpmatic and supportive care (antihistamines and ice)
- monitor for anyphylaxis
mare reproductive lost syndrome/ equine amnionitis and fetal loss
- ingestion eastern tent caterpillars
- early / late term abortion
- can also cause uveitis and pericarditis
toxicity of caterpillars moa
- caterpillar hairs penetrate intestine work way into bld stream and get trapped in capillaries, carry GI bacteria throughout body
fetal lesions with mare reproductive loss syndrome
- placenttis
- funisitis (inflam of umbilical cord)
lesions with mare reproductive loss syndrome
- unilaterally panopthalmitis
- pericardiits
- rarely encephalitis
two stripped walking stick
- chemical irritant can -> ulcerateve keratitis
True setea
- abdominal hair can -> irritation of skin (urticating hairs)
- tarantulas and caterpillars (some caterpillars have modified settea which can secrete)
blue tailed skink
- can -> liver failure if eat tail
puffer fish
- can -> liver failure if eat improperly prepared puffer fish
platapus
- males have poisons spurs
tetronodon
-venom in mouth
moles/ shrews
- have venoms
pittihui bitd
- produces poisin -> mouth numbness
