Toxicology Final - Venoms & Treatments

Lactrodectus is black widow
Loxosceles is brown recluse

Lactrodectus =
Loxosceles =

[Options are black widow and brown recluse]

Brown Recluse

More potentially lethal, worse symptoms, commonly confused with wolf spider

Brown recluse

Causes vascular damage and tissue necrosis; lethal via IV hemolysis, thrombocytopenia, hemoglobinuria and renal failure. [Which spider]

Black widow

Causes muscle pain, cramps, fasiculations, joint pain, headache, dizziness, and edema ; less often lethal but there is lots of pain and some neurotoxicity.

[Which spider]

Histamine

what component of bee/wasp venom makes it painful

connective tissue

Hyaluronidase breaks down what?

a) Micrurus

Coral snakes, Elapids (Cobras, Kraits, Death Adder)
[Fixed fangs; have to bite and chew ; less of a problem]

a) Micrurus
b) Crotalus
c) Sistrurus
d) Agkistrodon

b) Crotalus

Various RATTLESNAKES like timber, diamondback, etc - just not the pygmys or the big massassaugas.

a) Micrurus
b) Crotalus
c) Sistrurus
d) Agkistrodon

c) Sistrurus

Includes the largest (Massassauga) and smallest (Pygmy) rattlesnakes.

a) Micrurus
b) Crotalus
c) Sistrurus
d) Agkistrodon

d) Agkistrodon

TN Baddies: Copperhead and Cotton Mouth / Water Moccasins

a) Micrurus
b) Crotalus
c) Sistrurus
d) Agkistrodon

1. Pits on nose (thermal receptors)
2. Vertical pupils
3. Triangular heads

The typical characteristics of a venamous snake (rules of thumb) are...

1. Something on their nose
2. Something about their eyes
3. Something about their head shape

b) less likely to dry bite

Why are juvenille snakes more dangerous potentially?

a) More volume injected
b) less likely to dry bite
c) More potent venom when young

Volume

IF one of the two were true which would it be: A larger snake's venom is likely of a greater

volume or potency ?

Nose & Lower extremities

Where do we see snake bites (2 body parts)

Airway patency (obligate nose breathers)

The primary concern with envenomation in horses is

Go to the clinci

First line of Tx if someone asks you about a suspected snake bite?

Basic supportive care; monitor for up to 48hrs (24 in rattle snakes, 48 in elapids)

What is our first line of response for snake bites as the vet?

f) All of the above

Treatment for snake bites varies but may include:

a) Antivenins
b) Opioid analgesics
c) Blood replacement
d) Heparin or Warfarin
e) Antibiotics if severe necrosis
f) All of the above

a) Crotalids

Which of the following is associated with longterm sequelae in survivors of their bite? (Amputation, loss of function, etc from necrosis)

a) Crotalids
b) Elapids

1. Stabilize - ABCs
2. Clinical Evaluation
3. Decontamination
4. Enhance Elimination
5. Antidote?
6. Symptomatic Tx / Supportive Care

What are the 6 steps to consider in each poisoning case? [Santa Claus Dead, Elves Are Scared]

History
Physical Exam
Baseline Diagnostics (CBC, Chem, UA)

Begins as soon as you see dog (overlaps with stabilize) and continues the whole time.

Describe the basic elements of clinical evaluation in toxicological cases.

Major part of treatment; DIFFERENCE IN LIFE AND DEATH!!!

This decreases the total amount of toxin absorbed to hope its less than MLD.

Explain why decontamination is so important in poisoning cases

1. Stabilize - ABCs | Keep alive to make Dx and begin Tx
2. Clinical Evaluation | Determine severity and how to Tx
3. Decontamination | Decrease total amount of poison** absorbed
6. Symptomatic Tx / Supportive Care | Restore/preserve homeostasis

What is the goal for each of these? | Which is unique to poisons (not venoms)
1. Stabilize - ABCs
2. Clinical Evaluation
3. Decontamination
6. Symptomatic Tx / Supportive Care

the worst

When the dosage of a toxin is unknown assume..

1. Non vomiting species (horse, ruminant, rodent, reptile, bird, rabbit)
2. Not fully alert and conscious
3. Respiratory system compromised
4. Abnormal pharyngeal reflexes
5. Seizing/at risk of it
6. Already vomited multiple times
7. Toxin has a rapid onset (like alcohol)
8. Substance is gonna do more damage on the way up than letting it just pass or diluting it.

List contraindications for inducing emesis...

[7 of them.... 1. General species thing, 2. State of mind, 3-5. disease states kinda, 6-history based, 7&8 toxin based - obvious ones]

1. Seizure condition (epilepsy)
2. Heart disease
3. Megaesophagus
4. Abdominal/Chest Sx or Trauma

List conditions/situations where you would use caution inducing emesis (risk of toxin must outweigh risk of emesis).. [4]

a) Eyes - copious flushing; check cornea for ulcers after
b) Dermal - bathe, clip, brush, vacuum
c) Oral - flush mouth (milk, water, etc) , check cheek pouches
d) GI - emesis, lavage, AC, cathartics, chelators, Sx, etc.

Describe the various methods of decontamination for:

a) Eyes (1)
b) Skin (4)
c) Mouth (2, one species specific)
d) GI (5+)

1. Apomorphine: best in dogs (excites cats) - IV, one time only
2. Xylazine: noted for cats especially if they ate presurgery
3. Ropinirole: opthalmic solution - can give 2 doses

Describe the various methods of inducing emesis including which is best for which species...

[3; one dog, one cat, one newest]

1. Atropine
2. Xyaline
3. Ropinirole

Name that emetic agent:

1. Stimulates Dopaminergic receptors in the CRTZ in dogs
2. Activates alpha 2 receptors in the CRTZ - cats mostly
3. Agonist of Dopamine D2 agonist, newer, ophthalmic drops.

Directly in conjunctival sac/under eyelid or same place but dissolved in saline as a drops - wash after vomiting starts

Apomorphine comes in tablets and the most common weigh to use it for inducing emesis is what?

When decontamination is necessary but emesis is unsafe, and the risk of lavage are outweighed by the risk of toxin.

1. If patient is of altered mental status (not awake alert)
2. Patient has respiratory compromise
3. Emesis is unsuccessful or unlikely to be successful

Describe indications for performing gastric lavage

General idea

3 specific indications for choosing over emesis

Liquids: 1-4 hrs
Solids: 9-12hrs

How long until emesis is futile depends on a bunch of crap like the toxin, density of stomach contents, etc. So how long does it take liquid to completely leave the stomach at maximum? solids?

Radiographs

What can you do to see how full the stomach is?
Hint also tells us a decent amount of stuff like potentially info about the toxin, see some comorbidities, etc.

Best: Less than 30min
Reasonable: within 2 hrs
Eh: Over 4 hrs

Rules of Thumb for Emesis (timing)
- The sooner the better
- Less than _____ post ingestion is best
- Up to _______ is reasonable
- Greater than ______ is questionable

Guidelines; go case by case.

Aspiration

The biggest risk with emesis is...

3% H202

Best at home emetic if the animal isn't any of the DONTS, owner is compliant, and clinic is >30min away

Cat

Which is H202 emesis least effective in:

Dog, Cat, Ferret, Pig

1-2 times

How many times can an owner try H202 for emesis?

don't let them eat the vomit lol

After emesis what is the immediate next step?

Anesthesia and ET Tube

What two things are required for gastric lavage in SA but not in horses or ruminants?

lavage

Which has many more risks?

Emesis or Lavage?

Aspiration still (Check the cuff, put head down, check gag reflex)
Damaging the GIT
Causing fluid and electrolyte imbalances

3 big risks with lavage?

b) Cathartic - violently push GIT contents through lmao
d) LA (Gi fermentors, etc)

Polyethylene glycol is a...

a) emetic agent
b) Cathartic

is probably a bad idea in..

c) SA
d) LA

Oral chelators

What is used in LA for metal intoxications?

b) Deferoxamine

The chelator for iron?

a) EDTA
b) Deferoxamine
c) D-penicillamine

c) D-penicillamine

The chelator for copper?

a) EDTA

The chelator for lots of stuff; lead, mercury, more.
The chelator for iron?

a) EDTA
b) Deferoxamine
c) D-penicillamine

Best within 30 min; but never too late if toxin still in GIT (pretty inert so never really counterindicated..); also good for blocking enterohepatic recycling!!!

Debate over if its better before or after emesis

Describe the indications for administering activated charcoal.

1. Before | Pros: bind toxin immediately, more contents in stomach to vomit. Cons: Cannot analyze vomit, may have to repeat after lavage.

2. After | Pros: can analyze the vomit/lavage fluid, less toxin to need to absorb.

Pros/Cons for giving Activated charcoal...

1. Before Emesis
2. After Emesis

Hypernatremia

What ClinPath finding is sometimes seen when AC is given to very small dogs mostly?

All antidotes have risk; antidotes are specific to the toxin and receptor/target

Explain why there is no such thing as a universal antidote.

1. Diuresis - pee it out [usually just pump full of IV fluids]
2. Decrease enterohepatic recycling (AC over and over)

Ivermectin: IV Lipid Emulsion Treatment

Describe the 2 primary means of enhancing the elimination of toxicants.

What weird one is used in ivermectin poisoning?

True; not superior, not adequate amount of AC, bunch of filler with it

T/F: UAA gel sucks

b) Flumazenil

Poison: Benzodiazepines
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

a) EDTA, D-Penicllamine, etc.

Poison: Metals in general
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

c) Atropine but not 2-PAM

Poison: Carbamates
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine but not 2-PAM
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

d) Deferoxamine

Poison: Iron
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

4-methlypyrazone (Fomepizol) or Ethanol (if no 4-MP)

What are the two tx options for ethylene glycol toxicity?

e) Atipamezole

Poison: Medetomidine/Dexmetatomidine
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

f) 2-PAM (Pralidoxime) and Atropine

Poison: Organophosphates
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

g) Yohimbine or Tolazoline

Poison: Xylazine
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)

h) N-Acetylcystine (NAC)

Poison: Acetaminophen
Antidote:

a) EDTA, D-Penicillamine, etc..
b) Flumazenil
c) Atropine
d) Deferoxamine
e) Atipamezole
f) 2-PAM & Atropine
g) Yohimbine or Tolazoline
h) N-Acetylcystine (NAC)