Toxicology 2020

Question 1

Brittany’s neighbor came running over to her they’ll her that her two dogs got into an unknown amount of ‘squirrel bait’ that had been placed in an orchard next door. This is when you do the back door math! The smallest of the two dogs weighs 40 lbs, the active ingredient in the product called ‘Ramik’ is diphacinone (an anticoagulant rodenticide), diphacinone is present at .0005% in the bait, and a potential toxic dose in dogs is .3 mg diphacinone/kg BW.

Brittany induced vomiting with oral 3% hydrogen peroxide - insert the recommended dose: _________ mL.

Brittany then administered two doses of activated charcoal, four hours apart. It is very important to monitor this patient, at a minimum, for the next four hours to make sure that any fluid shifts do NOT result in a MAJOR electrolyte abnormality from occurring. Name the MAJOR electrolyte abnormality: ______________________.

A safe plan of treatment would be to have both dogs receive oral vitamin K1 therapy for __________ weeks.

Answer 1

40 mL
Hypernatremia
4 weeks

Question 2

Slobbering disease in livestock is due to a toxin called ______________________.

The fungus that produces the toxin preferentially likes to grow on __________ and __________ (name the two specific plants).

T/F: Excessive salivation seen in affected animals is due to acetylcholinesterase inhibition and the signs will resolve following atropine treatment.

Name the mycotoxin that exhibits weak estrogenic activity in cattle and swine: ________________.

Answer 2

Slaframine
Clover, alfalfa
False. Excessive salivation seen in affected animals is due to M3 agonism, not acetylcholinesterase inhibition.
Zearolenone

Question 3

Our own Leah Swannack called me with the following case. A rancher inadvertently administered 2 cc of Ivomec 1% into the carotid artery (instead of going SQ) of a two-mont-old, 200 lb calf who subsequently dropped like a rock and went into a seizure.

Leah’s mom, who is a DVM, successfully controlled the seizure with midazolam IV. The calf went home well sedated later that afternoon, and according to Leah, the calf was up and cursing the next day looking totally normal. Benzodiazepines are generally not recommended to control seizures in ivermectin exposed patients because they can prolong the sedation that is typically seen with ivermectin exposures. But there are not many pharmacological agents out there that can be sued in cattle to control seizures. Choose ONE answer below that describes ivermectin’s mechanism of action.

• Acetylcholinesterae inhibition
• Mimics acetylcholine at the nicotine sympathetic and parasympathetic postganglionic receptors
• Potentiates GABA- and glutamate-gated chloride channels
• Uncoupler of oxidative phosphorylation
• Reversible agonist of the inhibitory neurotransmitter glycine

Answer 3

Potentiates GABA- and glutamate-gated chloride channels

Question 4

Ivermectin is very safe if you use according to label instructions. Poisonings in dogs are VERY COMMON and exposures occur when dogs lap up from the ground what slobbers out of the horse’s mouth when clients are deworming them. Dogs that possess the MDR1 mutation are uniquely sensitive. Describe what MDR stands for AND describe the underlying mechanism as to why these dogs with the mutation are so sensitive to ivermectin.

Answer 4

Multiple Drug Resistance
The MDR1 mutation causes a lack of p-glycoprotein production, which is needed for active transport of ivermectin-like drugs through the blood-brain barrier and is needed for biliary and renal excretion. This causes a buildup of the drug in the brain with no way to leave, as well as prolonged half life because biliary and renal excretion is impaired.

Question 5

T/F: The severity of the clinical signs in ivermectin poisoned dogs is a good predictor of prognosis, and dogs that develop blindness rarely recover their vision.

Answer 5

FALSE

Question 6

Name the molluscicide that causes a ‘shake and bake’ syndrome in poisoned animals.

Answer 6

Metaldehyde

Question 7

Name the amino acid that is used as a urine acidifier in dogs to decrease damage to lawns, and in overexposures, can cause transient hindlimb paralysis and ataxia.

Answer 7

Methionone

Question 8

Select TRUE or FALSE for each of the statements below as it pertains to chocolate exposures in animals.

GI absorption of both caffeine and theobromine is rapid and there is little variation in sensitivities in dogs and cats with respect to toxic and lethal doses.

Theobromine, the main methylxanthine in chocolate, has a long half-life due to enterohepatic recirculating and delayed gastric emptying.

Low dose methylxanthine exposures cause vomiting, diarrhea, excessive urination and bloat, while high dose exposures cause hyperactivity, muscle tremors, tachycardia, elevated blood pressure and cardiac arrhythmias.

The treatment option of utilizing multiple doses of activated charcoal (three doses in 24 hours) should be reserved for high dose exposure patents who did not vomit, because the activated charcoal and the high sugar content of chocolate can contribute to a higher risk of the patient developing an electrolyte disorder due to fluid shifts.

Answer 8

GI absorption of both caffeine and theobromine is rapid and there is little variation in sensitivities in dogs and cats with respect to toxic and lethal doses. (FALSE)

Theobromine, the main methylxanthine in chocolate, has a long half-life due to enterohepatic recirculating and delayed gastric emptying. (TRUE)

Low dose methylxanthine exposures cause vomiting, diarrhea, excessive urination and bloat, while high dose exposures cause hyperactivity, muscle tremors, tachycardia, elevated blood pressure and cardiac arrhythmias. (TRUE)

The treatment option of utilizing multiple doses of activated charcoal (three doses in 24 hours) should be reserved for high dose exposure patents who did not vomit, because the activated charcoal and the high sugar content of chocolate can contribute to a higher risk of the patient developing an electrolyte disorder due to fluid shifts. (TRUE)

Question 9

All of the following are TRUE regarding the two mycotoxin diseases perennial ryegrass staggers and equine leukoencephalomalacia EXCEPT (select ONE BEST answer):

• Equine leukoencephalomalacia is also called moldy corn poisoning and is due to a group of toxins called fumonisins.
• Perennial ryegrass staggers is caused by an endophyte growing in the lower leaf sheath and seed, producing a group of compounds called lolitrems.
• Perennial ryegrass staggers exhibits low morbidity and high mortality in a group of affected animals where equine leukoencephalomalacia exhibits high morbidity and low mortality in a group of affected animals.
• Fumonisins have been shown to cause hepatic lesions at a high enough exposure dose in all animals tested thus far.

Answer 9

FALSE - Perennial ryegrass staggers exhibits low morbidity and high mortality in a group of affected animals where equine leukoencephalomalacia exhibits high morbidity and low mortality in a group of affected animals.

Question 10

A group of 17 adult cows with calves were turned out into a pasture that had not been utilized for two years. Within 36 hours, 5 adult cows and 1 calf were recumbent, breathing heavily, and unable to rise. Two cows died shortly after the DVM arrived, and she was allowed to perform field necropsies on both cows. Fixed and fresh tissues were submitted to WADDL and the MAIN histologic lesion observed was: acute, severe, proximal renal tubule necrosis with birefringent crystals within the lumen of tubules and collecting ducts. This lesion is MOST consistent with: select ONE BEST answer.

Quercus sp. (oak)

Halogeton glomeratus (halogeton)

Philodendron sp. (philodendron)

Cruciferae family (mustard)

Senecio vulgaris (common groundsel)

Answer 10

Halogeton glomeratus (halogeton)

Question 11

Dr. Robert Thonney was called out to necropsy two dead pregnant heifers, out of a group of 8, that were found on opposite ends of a pasture. The clients check the cows once daily and did not see any signs of illness prior to finding them dead. They pasture has grass coming up, and the owners supplement the animals with alfalfa hay bales. Well water pumped from the hose is the cow’s water source. There is a moderately sized burned metal pile in the middle of a the pasture, which the owners claim has been there for years and the cows don’t go near it. Dr. Thonney performed field necropsies on both heifers and will be submitting fixed and fresh tissues to WADDL for analysis.

Dr. Thonney and I discussed the possibility of nitrate poisoning, because nitrate is one toxin that can cause ‘acute’ death. Name the BEST postmortem sample to collect from the two dead heifers to confirm a nitrate intoxication: _____________.

We also discussed the possibility of lead poisoning, because this is a common poisoning we see in the early spring when cattle are let out to graze new pastures. Name the MOST COMMON source of lead for cattle: _________________.

Answer 11

Eyeball

Batteries

Question 12

Dr. Robert Thonney was called out to necropsy two dead pregnant heifers, out of a group of 8, that were found on opposite ends of a pasture. The clients check the cows once daily and did not see any signs of illness prior to finding them dead. They pasture has grass coming up, and the owners supplement the animals with alfalfa hay bales. Well water pumped from the hose is the cow’s water source. There is a moderately sized burned metal pile in the middle of a the pasture, which the owners claim has been there for years and the cows don’t go near it. Dr. Thonney performed field necropsies on both heifers and will be submitting fixed and fresh tissues to WADDL for analysis.

Ninety percent of lead poisoned cows exhibit signs associated with the central nervous system AND the peripheral nervous system - list several of the MOST COMMON clinical signs related to these two systems you would expect to see in affected cows.

Answer 12

Blindness, dysphagia, convulsions, eyelid snapping

Question 13

Dr. Robert Thonney was called out to necropsy two dead pregnant heifers, out of a group of 8, that were found on opposite ends of a pasture. The clients check the cows once daily and did not see any signs of illness prior to finding them dead. They pasture has grass coming up, and the owners supplement the animals with alfalfa hay bales. Well water pumped from the hose is the cow’s water source. There is a moderately sized burned metal pile in the middle of a the pasture, which the owners claim has been there for years and the cows don’t go near it. Dr. Thonney performed field necropsies on both heifers and will be submitting fixed and fresh tissues to WADDL for analysis.

Name the TWO tissues that Dr. Thonney must submit to analytically confirm the presence of lead.

Answer 13

Kidney and liver

Question 14

Two bald eagles were found down in a field near a dead horse that multiple scavengers had been seen feeding from. Both eagles died prior to arriving to the WSU-VTH, and one was exhibiting limb paresis. Initially we tested the eagles for pentobarbital, given the history of seeing these types of poisonings following birds scavenging euthanized carcasses. Pentobarbital testing came back negative on both eagles, but both were confirmed to have TOXIC lead levels.

Name THE MOST COMMON source of lead for bald eagles - where are they picking this lead up?

Name the BEST chelator that can be administered ORALLY to treat lead poisoned dogs, cats, and birds.

Answer 14

Scavenging animals shot with lead shot

Succimer

Question 15

Dr. Richard Old, who was to conduct your plant walk this semester, called and was concerned about a group of cows that his tenant introduced into his pasture that quickly mowed down the plant below - and it just so happened that Ayala spied the same plant while on her walk with Hank and Laska. The pppppppurple spots means it must be ______________________.

Answer 15

Poison hemlock

Question 16

Explain SPECIFICALLY why you see severe extensor rigidity of all four limbs, along with tonic seizures, in strychnine poisoned dogs.

Answer 16

Strychnine reversibly antagonizes the inhibitory neurotransmitter glycine.
Without inhibitory input, reflex extension and tonicity predominate, because only activating input remains.

Question 17

Ollie, a seven-month-old 21.3kg FS German Shepherd dog presented to the WSU-VTH after ingesting bromethalin-containing rat poison. It was estimated that she may have eaten about six, one-ounce blocks, each containing .01% bromethalin, two hours prior to presentation. The entire physical examination was normal.

Assess the vital signs:
T: 102.1 F
P: 150 beats/minute
R: 30 breaths/minute

Emesis was induced in the clinic successfully with IV __________, and this was followed 20 minutes later with an anti-emetic __________________.

Answer 17

T: 102.1 F (NORMAL)
P: 150 beats/minute (HIGH)
R: 30 breaths/minute (NORMAL)

Apomorphine, maropitant

Question 18

Ollie, a seven-month-old 21.3kg FS German Shepherd dog presented to the WSU-VTH after ingesting bromethalin-containing rat poison. It was estimated that she may have eaten about six, one-ounce blocks, each containing .01% bromethalin, two hours prior to presentation. The entire physical examination was normal.

The recommendation was to orally administer THREE doses of activated charcoal, every 8 hours, over the next 24 hours - WHY three doses? BE SPECIFIC.

Answer 18

With bromethalin toxicity aggressive decontamination is necessary as bromethalin undergoes significant enterohepatic recirculation.

Question 19

Ollie, a seven-month-old 21.3kg FS German Shepherd dog presented to the WSU-VTH after ingesting bromethalin-containing rat poison. It was estimated that she may have eaten about six, one-ounce blocks, each containing .01% bromethalin, two hours prior to presentation. The entire physical examination was normal.

The reason math is so important in Ollie’s case is because dogs that receive exposure doses LD50 may experience the _________________ syndrome. This may impact your future treatment plans and decisions made by the owner based on prognosis.

Answer 19

< LD50 - paralytic

> LD50 - convulsant

Question 20

Ollie, a seven-month-old 21.3kg FS German Shepherd dog presented to the WSU-VTH after ingesting bromethalin-containing rat poison. It was estimated that she may have eaten about six, one-ounce blocks, each containing .01% bromethalin, two hours prior to presentation. The entire physical examination was normal.

The DVM working the case up decided to give IV lipid therapy - provide ONE good reason why it is NOT currently recommended to give this treatment, for this specific case, prior to the onset of clinical signs.

Answer 20

May actually enhance absorption of bromethalin

Question 21

A two-year-old MN DSH indoor cat presented to a clinic in Moscow for hypersalivating, ataxia, and whole-body muscle tremors. The owners indicated that they had applied a permethrin spot-on product on their dog two hours prior to noticing the signs in the cat. The two pets are great buddies and share the same bedding material.

Name the SPECIFIC drug you should use to control the tremors: _____________________.

T/F: Atropine should be used to control the hypersalivation.

While cats are extremely sensitive to the pyrethroid named permethrin, dogs are extremely sensitive to the pyrethroid named _________________.

Answer 21

Methocarbamol
FALSE
Bifenthrin

Question 22

Ergot and fescue poisonings are very common and affected animals exhibit very similar clinical problems. ALL of the following are TRUE regarding these two mycotoxins EXCEPT (select ONE BEST answer):

• Ingestion of either ergot or fescue can lead to vascular vasoconstriction, and in the winter months this can lead to a clinical syndrome known as fescue foot - dry gangrene of the distal extremities (feet, tail, ears).
• Summer slump occurs in cattle exposed to fescue during hot times, due to vascular vasoconstriction that impairs the ability of animals to dissipate heat.
• Abortions may occur following exposure to either fescue or ergot, and fescue exposures in pregnant horses have led to prolonged gestation, thickened placentas, and birth of large, weak dysmature foals.
• Ergot and fescue poisoned pregnant cows and horses may display early signs of milk production prior to parturition due to enhanced prolactin secretion via stimulation of the dopaminergic receptors.
• The sclerotia body or ergot is a mass of mycelia fungal growth that can be visualized replacing the normal seed of the plant, while the fungus associated with fescue is an endophyte that cannot be seen and invades internal plant tissue.

Answer 22

FALSE - Ergot and fescue poisoned pregnant cows and horses may display early signs of milk production prior to parturition due to enhanced prolactin secretion via stimulation of the dopaminergic receptors.

Question 23

A cat presented to a DVM after ingesting 1/3 of several leaves from an Easter Lily plant (Lilium sp.) that had been placed on the top of the refrigerator. At the clinic, the cat was administered two doses, 15 mL each, of oral 3% hydrogen peroxide to induce vomiting - AAARRRRGGGGGHHHHHHHH! I am somewhat impressed that this DVM was even able to do this.

You will NEVER do this! Why?

A very effective emetic to use in cats is ______________________, and once you do this, whether the patient actually vomits or not, you can reverse the sedative signs by using _____________________.

Answer 23

High risk of hemorrhagic gastroenteritis

Dexmedetomidine, atipamezole

Question 24

Urea is a common non-protein nitrogen feed additive used in cattle, in lieu of directly adding protein to the diet - urea is cheap, protein is expensive. Describe how urea works in a cow as a feed additive AND describe the pathogenesis of poisonings.

Answer 24

Urea and water are converted to ammonia and CO2 with the enzyme urease.
The microflora get overwhelmed by the NH3, so the rumen buffers it to NH4/ammonium.
However, NH4 does not cross the rumen wall readily, causing the rumen pH to increase.
This causes rumen alkalosis and metabolic acidosis, eventually leading to hyperkalemia-induced cardiac failure.

Question 25

NAVLE just loves to ask this question. Select the best treatment option for urea poisoned ruminants: (select ONE answer only)

• Sodium thiosulfate
• Cold water and weak acetic acid (vinegar)
• Methylene blue
• Calcium gluconate, IV
• Thiamine, vitamin B1

Answer 25

Cold water and weak acetic acid (vinegar)

Question 26

A four pound, three-year-old FI Chihuahua dog named Lily ate two marijuana brownies the night before presentation. At presentation, she was: lethargic, dribbling urine, not walking normally, dragging her hind legs, extending her neck while looking at the ceiling, exhibiting right forelimb and eye twitching, and had tacky mucous membranes. The owner of the dog called a local clinic and was told ‘…the best thing to do would be to give Lily chicken broth and canned food…and bring Lily to the clinic in 2-4 weeks for a chemistry panel.’ Excuse my language, BUT what the heh????? Describe to me what ALL this advice is wrong AND describe to me what you would have recommended for treatment AND name one other substance that could be in that brownie that might be problematic for Lily:

Why wrong:

What would you recommend?

Name of one other compound:

Answer 26

Why wrong: ?

Recommendation: ?

Another problematic compound: Theobromine

Question 27

Name the TWO tremorgenic mycotoxins that are likely to be found in compost piles, where Penicillium molds like to grow, and can cause intention tremors, ataxia, nystagmus, and sensitivity to external stimuli in poisoned patients.

______________________________ and __________________________

Answer 27

Penitrem A

Roquifortine

Question 28

Our own Christina’s dog River once ate approximately three pounds of raisins that she had purchased to make some bulk trail mix. Luckily, River was presented within a few hours of ingesting the raisins - needless to say he survived. ALL of the following would be reasonable diagnostic/treatment options EXCEPT (select ONE BEST answer):

• Emesis, followed by an antiemetic and activated charcoal
• Establish baseline CBC, serum chemistry panel, and urinalysis
• Liver protectants (SAMe, n-acetylcysteine) oral, for two weeks
• IV fluid therapy, LRS, for 48 hours

Answer 28

Liver protectants (SAMe, n-acetylcysteine) oral, for two weeks

Question 29

Organophosphate pesticides, carbamate pesticides, and some neurotoxin Cyanobacteria inhibit the enzyme _______________________ that will cause the affected animal to exhibit muscarinic and nicotinic signs.

Answer 29

Acetylcholinesterase

Question 30

The mnemonic I want you to remember for the muscarinic signs is DUMBSLED: name all 8 signs.

Answer 30

Diarrhea
Urination
Myosis
Bradycardia
Salivation
Lacrimation
Dyspnea

Question 31

Name the drug you will use in organophosphate poisoned animals that mimics the binding site on the enzyme above, thus reactivating the enzyme and allowing for the drug-OP complex to be excreted in the urine: _______________.

Answer 31

Oxime

Question 32

MUSHROOMS CAN DO ALMOST EVERYTHING AND ANYTHING! Most mushroom exposures occur in puppies, and this is the time of year we start to get calls. A woman was out for a walk on a path in a wooded area when she noticed that her two-year-old FS Border collie mix dog Allie had stopped and was chewing on something. She went over and noticed it was a mushroom. Within two hours, Allie had vomited twice and was exhibiting excessive salivation. Allie arrives at the clinic 30 minutes later. ALL of the following are TRUE statements regarding mushroom poisonings and the above case scenario EXCEPT (select ONE BEST answer):

• Your focus on treatment is to control signs and/or prevent signs from occurring that are associates with six major problems mushrooms can cause: gastroenteritis, muscarinic signs, CNS excitiation, CNS depression, liver disease, and intravascular hemolysis.
• Regardless of the type of mushroom ingested, most poisoned patients start of displaying GI signs. You should consider administering an antiemetic to Allie, along with atropine to control the salivation.
• Establish baseline serum chemistry panel data and hospitalize Allie for 24 hours while providing adequate fluid therapy and monitoring for signs.
• If possible, email an image of the mushroom to a mycologist for identification.
• After 24 hours, if deemed appropriate, Allie can be discharged with two weeks’ worth of liver protectants (SAMe, n-acetylcysteine) and recommend a follow-up biochemistry panel in 24-48 hours post discharge.

Answer 32

FALSE: - Your focus on treatment is to control signs and/or prevent signs from occurring that are associates with six major problems mushrooms can cause: gastroenteritis, muscarinic signs, CNS excitiation, CNS depression, liver disease, and intravascular hemolysis.

Question 33

Cynder, a five-year-old FS poodle mix presented to the VTH ECC for evaluation after eating approximately four cups of sourdough starter. When this happens, the carbohydrate (sugar) reacts with the yeast in the starter in the nice warm environment of the stomach to produce both ________ and _________ that can then create all kinds of problems.

Answer 33

CO2 and ethanol

Question 34

You run an iSTAT chemistry panel on an ethylene glycol poisoned patient. Explain SPECIFICALLY WHY the low calcium, low TCO2, and high P are consistent with Stage 1 and Stage 2 of ethylene glycol toxicosis.

Answer 34

Low calcium: Ca is being formed into Ca oxalate crystals

Low TCO2: EG metabolites are acidic

High P: Rust additive in anti-freeze contains P

Question 35

How do you calculate anion gap?

Answer 35

Na + K - (TCO2 + Cl)

Question 36

Bubbles, a 13-year-old FS 29kg Collie dog presented to the VTH ECC for ingestion of LOTS of medications and supplements (18 different ones - I am not making this up!). We are going to focus on two of these items only: she ingested one 1000 IU vitamin D tablet and six 200mg ibuprofen tablets.

ALL of the following would be considered in the treatment of cholecalciferol poisoning AND ibuprofen poisoning in the same dog who is symptomatic (like the one above) EXCEPT (select ONE BEST answer):

• IV physiologic saline, 2-3 times maintenance for 48 hours
• Misoprostol
• SAMe and N-acetylcysteine
• Monitor BUN, Cr, Ca, P, USG
• Omeprazole
• Bisphosphonate

Answer 36

SAMe and N-acetylcysteine

Question 37

Sodium monofluoroacetate is a pesticide that has limited use in the US but is used in other places around the world. It often goes by the name of ___________.

Answer 37

1080

Question 38

This is why you do necropsies, because history is not everything! This information was provided by the submitting DVM on the paperwork - Species: goat; breed: assorted; location of lesion: liver; number in group: 400; number dead: 30 kids; duration of problem: 1 week; History: ‘ten days ago the neighbors sprayed an adjoining field and death loss in the kids started shortly after that. We will find out what the spray was soon. Two of the three kids I necropsies had mottled livers and non-clotting blood in the vessels and abdomen. One had a tear in the liver.’ Three intact goat kids were submitted to WADDL for necropsy, and all three goat kids had similar gross and histologic lesions: cardiac myodegeneration and necrosis, chronic, multifocal, severe; thyroid hyperplasia, moderate to severe (goiter).

In the PNW, goiter is common because the soils are typically low in ____________. However, there are plants that we talked about in class that can interfere with that element’s uptake and subsequent metabolism - name the plants: ______________. And the cardiac myodegeneration is due to a deficiency of _____________ (name an element).

Answer 38

Iodine
Mustards
Selenium