Toxicology Flashcards by Kelsey Thornton

What are 2 of the most important factors in order to develop a differential list for toxicoses?

system affect (ex. CNS, GI, Renal)
Onset of clinical signs (<1d, 1-5d, >5d)

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Fill in the following:
1 mL = ___ gram
16 oz = ___ pounds/pints
2 pints = ___ quarts
__ quarts = 1 gallon
1 fl oz = ___ mL
% = _____

1 mL = 1 gram
16 oz = 1 pound/pint
2 pints = 1 quart
4 quarts = 1 gallon
1 fl oz = 30 mL
% = grams/100 mL

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Insecticides (OPs, carbamates, neonicotinoids, etc.) generally target which body system?

nervous system

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Insecticides (OPs, carbamates, neonicotinoids, etc.) increase the action at _____ receptors.

acetylcholine

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What diagnostic test can you perform to confirm/deny a OP or carbamate toxicosis?
(this if a form of early diagnosis)

low, pre-anesthetic dose of ATROPINE
if the eyes dilate, HR increase, &/or salivation stops within 5-10 min, then the patient does NOT have OP or carbamate toxicosis

if no changes occur, give antidotal dose of ATROPINE

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What is the confirmatory diagnostic for OP and carbamate toxicosis?

Measure acetylcholinesterase activity of heparinized whole blood and/or brain tissue
>70% reduction in activity is diagnostic

you could also do analysis of bait residues, stomach contents, and urine for OP or carbamate.

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What is the treatment for OP or carbamate toxicosis?

ATROPINE – muscarinic receptor antagonist (parasympatholytic)
+ 2-PAM

careful not to overdose and get atropine toxicosis

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T/F: there is no antidote for bromethalin toxicity

true – this rodenticide targets the CNS. there is not an antidote, so treatment is to decontaminate.

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Vitamin K antagonist rodenticide toxicity targets which body system?

hematopoietic system

they are treated with vitamin K

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Cholecalciferol rodenticides target which body system?

kidneys

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strychnine targets which body system?

CNS

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T/F: lead toxicosis has multi-systemic effects (CNS, GI, kidney)

true

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what body system does sodium toxicity effect?

nervous system (from water deficiency)

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What body system does zinc toxicosis effect?

hematopoitic

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What body system does arsenic toxicosis effect?

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what body system(s) does iron toxicosis effect?

GI and liver

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what body system is affected by selenium deficiency?

muscle

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what body system does aflatoxin affect?

aflatoxin is found in corn mainly in hot, dry seasons
GI (liver)

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what body system is affected by zealenone and vomitoxin?

vomitotoxin is found in small grains during cool, wet seasons – affects GI
zealenone co-exists with vomitoxin and affects the reproductive system

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what body system is affected by penitrem A?

penitrem A is found in rotting dairy products and/or garbage.
it affects the nervous system

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what body system does roquefortine affect?

found in rotting compost/garbage
affects the nervous system

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what body system does fumonisin affect?

found in mold corn
affects the nervous system

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The ______ makes the poison

dose

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Bulbs (daffodils, tulips, irises, hyacinths, etc.) are not usually lethal but contain irritant resins, alkaloids, and/or insoluble calcium oxalate. What body system in affected by ingestion?

GI – salivation, vomiting, diarrhea within 1 hr of consuming

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what is the tx for bulb toxicosis?

decontamination, activated charcoal, cerenia, symptomatic txs

what is the toxic component of Narcissus (daffodils, narcissus, lent lily) that cause GI (vomiting, diarrhea) and skin issues (dermatitis)?

alkaloids, insoluble oxalate crystals

T/F: onions are toxic in all forms (raw, cooked, dehydrated, or powder)

true the toxic dose is 0.5% of body weight

what is the mechanism of toxicity for onions?

cause oxidative damage to RBCs and lead to RBC lysis

what is the tx for onion toxicosis?

decontamination symptomatic

T/F: mistletoe, holly berries, and poinsettias all affect the GI system

true they cause anorexia, lethargy, vomiting, diarrhea, etc. christmas trees can have liver, kidney, and CNS involvement too (can see icterus)

what is the tx for christmas plant toxicosis?

symptomatic (fluids, antiemetic, demulcents)

T/F: christmas cactus is extremely neprhotoxic to pets

false -- not generally toxic to pets, but may cause mild GI upset.

What 2 things are MORE toxic to cats?

onions pine

what are the toxic components in the various cardiotoxic plants (christmas kalanchoe, foxglove, lilly of the valley, common oleander, yellow oleander)?

cardioactive steroids (Digoxin and oleandrin, plus others) the mechanism is inhibition of Na/K/ATPase pumps --> impaired conduction, bradycardia, dysarrythmias

how do you diagnose patients with cardiotoxic plant toxicity?

they will have GI and cardiac signs - clin path = hyperkalemia - ECG abnormalities -- various arrhythmias, AV block, brdycardia, etc. - hypersalivation, v/d, etc. death usually occurs from asystole and VFIB

what is the tx for cardiotoxic plant ingestion?

- aggressive decontamination - activated charcoal (multi. doses) - atropine or glycopyrrolate (increase HR) - lidocaine (for arrhythmias) - +/- beta blockers (propanolol, esmolol) - Digoxin-specific Fab fragments ($$$)

what are 2 cardiotoxic plants that cause hyperkalemia and ECG abnormalities predominately in horses and cattle from contaminated hay?

Dogbane Broadleaf milkweed

what is the primary toxic principle in tobacco causing nervous system and GI effects, as well as indirect cardiotoxicity?

nicotine (alkaloid) it is toxic at 1 mg/kg

how do you treat tobacco toxicity?

remove residual tobacco assist respiration stabilize heart and BP

What is the toxic principle in Yew?

taxine alkaloids they cause bradycardia, hypotension, and cardiac arrest with a FAST onset. they can cause sudden death.

How do you diagnose yew toxicity?

- taxine in stomach contents - sudden death - wide QRS

what is the tx of yew toxicity?

1. atropine 2. activated charcoal 3. saline cathartic prognosis is guarded.

What is the toxic principle in Rhododendron, azaleas, and Mt. Laurel?

grayanotoxins which cause heart arrythmias and vomiting/regurg, seizures, and death due to arrhythmias

how do you treat rhododendron, azalea, or mt laurel toxicity?

1. stop vomiting with acepromazine 2. give activated charcoal and saline cathartic 3. treat arrythmias (lidocaine if tachycardia, atropine if bradycardia)

T/F: ingestion of shrubs can cause cardiac arrest

true

T/F: vomiting is most likely to occur with yew ingestion than rhododendron

false -- rhododendron

what is the toxic principle of buckeye?

Aesculin causes ataxia, muscle tremors, and goose-stepping

how do you treat buckeye toxicity?

1. sedate so they dont traumatize themselves

What will be the result of a horse ingesting shavings of heartwood bedding (black walnut)?

constriction of blood vessels in hoof wall --> acute laminitis, +/- colic

how do you treat black walnut toxicosis?

1. remove shavings, wash legs 2. activated charcoal, cathartic, mineral oil 3. acepromazine, DMSO 4. prazosin (to vasodilate) 5. pain meds 6. soft bedding for support

T/F: acorns from all Quercus spp. (oak) are considered toxic

true (white oaks, black oaks, red oaks, western shrub oak) although they'd need to eat ~50% of their diet.

what is the toxic principle of oak?

gallotannin gallic acid and its metabolite (pyrogallol) are astringents clinical signs are ventral edema, dyspnea, severe dehydration, blacl/tarry/fetid diarrhea, colic.

what is the ultimate result of oak toxicosis?

renal failure will find increased BUN/creatinine, decreased Na, Cl, Ca, +/- K, and increased Mg. there will also be perirenal edema.

what is the tx for oak toxicosis?

1. fluids and electrolytes 2. rumenatorics (restore rumen with vit B), transfaunation, prop glycol 3. 10% calcium hydroxide

why can feeding high proline diets serve as a preventative measure for oak toxicosis?

high proline foods bind tannins in the gut

what is teh biggest differential for oak toxicosis?

redroot pigweed which also causes perirenal edema

what is the toxic principle of red, sugar, and silver maples?

aceritannin causes hemolysis and MetHb formation

which species is MOST sensitive to maple toxicity?

equine

what 3 body systems are affected by maple toxicity?

RBCs -- hemolysis, methemoglobinemia, heinz body anemia, cyanosis Hepatic -- icterus Renal -- tubular nephrosis

How do you tx maple toxicity?

1. activated charcoal and saline cathartic 2. blood transfusion if hypoxic 3. absorbic acid to reduce MetHb 4. fluids and pain meds (no steroids)

what are 3 important cyanogenic plant sources?

1. wild black cherry 2. chokecherry 3. sorghum (johnson grass, sudan grass, etc.)

T/F: the wilting stage of plants that contain cyanide are considered to be the most hazardous

true

Which species are most affected by cyanide toxicity?

ruminants -- especially goats

what is the mechanism of action for cyanide toxicity?

cyanide binds cells become unable to utilize oxygen cells suffer from anoxia even though they have oxygen blood is cherry red (superoxygenated)

what are the most common clinical signs of cyanide toxicosis?

- bright red MM - sudden death - bitter almond/bleach smell to rumen

how do you tx cyanide toxicity?

1. thiosulfate 2. nitrite (creates methemoglobinemia) 3. hydroxocobalamin (vitB12)

The key differentiating factor between nitrate toxicity and cyanide toxicity is the color of the blood -- nitrate = brown blood, cyanide = bright red. Why is it so important to distinguish between the two toxicities?

treatment! for cyanide toxicity, we give nitrite which creates methemoglobinemia. We would NOT want to do that in a case of nitrate toxicity because methemoglobinemia is already present.

From the following, which is MOST liekly to cause sudden death A. buckeye B. oak C. maple D. black walnut E. wild cherry

E. wild cherry

From the following, which is/are of special concern in horses? A. buckeye B. oak C. maple D. black walnut E. wild cherry

c. maple d. black walnut

From the following, which causes non-lethal neurotoxicity? A. buckeye B. oak C. maple D. black walnut E. wild cherry

a. buckeye

Risk for toxicity = hazard + _______

exposure

Why must you ensure you do not discard, modify, or give samples away in a toxicity case?

chain of custody

T/F: toxicology testing helps shorten your differential list but is NOT a method of establishing a differential list.

true

T/F: when storing samples ofr toxicology testing, they should NOT be stored in the same container or pooled.

true

what tube top color will cause false elevation of zinc due to exposure to rubber?

royal blue

what samples can be taken for ante-mortem toxicology testing?

whole blood serum plasma urine feces vomit stomach contents (from lavage)

which samples should always be taken from dead animals for toxicology testing?

brain liver kidney urine GI contents

What treats topical pyethroid insecticide toxicosis?

dermal decontamination

what is the goal of decontamination?

prevent further absorption of the toxin this can be done by emetics, activated charcoal, washing/dilution/ion trapping, etc.

what are the 4 emetics used for decontamination?

1. hydrogen peroxide 3% 2. Apomorphine (opioid and D2 agonist; dogs) 3. Ropinirole (Clevor eye drops) 4. Xylazine (Alpha-2 agonsit; cats)

what is an adverse effect of using activated charcoal (an adsorbent)?

hypernatremia