poison venom

land venomous creatures

bees, wasps, spiders, scorpions, snakes, lizards

sea venomous creatures

jellyfish, snails, sea stars, sea urchins

poisonous definition

you bite the thing → toxicity

venomous definition

the thing bites you → toxicity

(snakes are ___, snakes are not predatory towards humans)

types of snakes in north america

pit vipers, coral snakes

general bite management

ABCs (intubate, fluids for hypotension if necessary) 

analgesia ± anxiolysis

local wound care – irrigate with sterile water

• Tetanus prophylaxis (vaccine)

• prophylactic antibiotics are NOT necessary

Tdap or Td vaccine

given if last dose was over 5 years ago

(rationale: dirt and soil causing exposure, not snake)

do NOT do to snake bite

suck the venom out

apply tourniquet or pressure bandages

drain bite site

capture/decapitate snake

pit vipers

found in the south

ex: rattlesnakes, copperheads, cottonmouths

single row of plates = venomous

pit viper venom

mixture of proteins + enzymes that cause local tissue damage, coagulopathies, neurotoxic effects

(composition varies among snakes)

pit viper bite symptoms

puncture marks, pain and severe swelling at bite site that can progress to hemorrhagic bleb (can become necrotic)

coagulopathy (decreased fibrinogen and platelets, increased PT time and INR)

minor neurotoxicity

naus/vom, tachycardia, anaphylactic reactions (pruritus/urticaria, wheezing – more likely if prior exposure to venom)

(dry bite, no venom but delayed symptoms)

pit viper bite diagnosis

quantify swelling (monitor distance from bite and circumference - initially + every 15 minutes until progression stops)

labs (initially + every 6 hours)

CBC, platelets, PT/INR, aPTT, fibrinogen

pit viper bite management

ABCs

maintain limb at heart level – do NOT elevate

pain: intravenous opioids

• avoid NSAIDs (inhibit platelet function), ice packs (thermal damage)

life-threatening bleeding → blood products BUT must be given with antivenom

pit viper antivenom indication

severe swelling (extends past 1 major joint, necrosis)

coagulopathy (PT >15 sec, fibrinogen <150 mg/dL, platelets <150K cells/µL)

systemic signs of envenomation (hypotension, anaphylaxis, neurotoxicity)

CroFab (FabAV) composition

ovine (sheep) from american snake venom, papain - cleavage agent

allergy → latex, sheep, papain, papaya, pineapple, bromelain

MORE EXPENSIVE

CroFab dose

initial dose = 4-6 vials and repeat until symptoms are controlled (no progression of swelling, no worsening of coagulopathies, resolution of neurotoxicity)

maintenance dose = 2 vials q6h x 3 (after symptoms are controlled)

Anavip (FabAV) composition

equine (horse) from south american snake venom, pepsin - cleavage agent

allergy → horse, pepsin

Anavip dose

initial dose = 10 vials

maintenance dose = 4 vials prn

pit vip antivenom monitoring

every 1 hour – PT/INR, PTT, platelets, fibrinogen, progression of swelling

pit vip antivenom ade

delayed hypersensitivity reactions (3 weeks)

when to stop antivenom

(all 3)

• swelling stops progressing

• blood labs are trending toward norma

• systemic symptoms are resolved 

antivenom counseling points

repeat labs in 3-5 days

• rule out recurrent coagulopathies

avoid bleed risk activites for 14 days

• procedures, work

hypersensitivity reactions may occur with future antivenom use

monitor for signs of serum sickness

• 5-24 days after receiving antivenom

• N/V, malaise, fever, urticaria, myalgia, arthralgia, lymphadenopathy

coral snakes

found in gulf state during summer months

“velcro” fangs

red and yellow = venomous

coral snake venom components

alpha neurotoxin - blocks ACh receptors

coral snake bite symptoms

may take hours for symptoms to develop

slurred speech, ptosis (droopy eye)

weakness → paralysis

coral snake bite management

• close clinical observation: minimum of 24 hours

• intubate at earliest signs of bulbar paralysis (muscles involved in speech, swallowing, and facial movement)

• any symptoms → antivenin (if you can get it)

antivenin

equine (horse), requires skin testing before administration

counseling on serum sickness