Lecture 1: Introduction to Veterinary toxicology

Define poison.

A substance that is capable of causing illness or death of a living organism when introduced or absorbed.

Define toxin.

A poisonous substance that is a specific product of the metabolic activities of a living organism; usually very unstable, notably toxic when introduced into tissues, and typically capable of inducing antibody formation.

Define venom.

A toxic substance produced by some animals (e.g., snakes, scorpions, bees) that is injected into prey or an enemy chiefly by biting or stinging, causing injurious or lethal effects; broadly distinguished as: "If you bite it and die, it's poison. If it bites you and you die, it's venom."

What is Step 1 of toxicological analysis and what is it based on?

List toxicological differentials, based on signalment, history, clinical signs, and other diagnostics.

What is Step 2 of toxicological analysis?

Obtain appropriate samples, noting that different toxins are detectable in different matrices.

What is Step 3 of toxicological analysis?

Determine the appropriate extraction technique (e.g., making colorful solids into clear liquids).

What is Step 4 of toxicological analysis?

Determine the appropriate analysis method.

What is Step 5 of toxicological analysis and what does it involve?

Interpret results, considering clinical significance and whether findings are qualitative or quantitative.

What are the three basic steps in formulating a toxicological differential list?

1. History - signalment, signs/onset/progression, other animals affected/exposed, environment (indoor/outdoor, plants, landscaping), medical history, diet/water/supplements.

2. Examination - physical exam, postmortem exam, and comparing findings to the history.

3. Baseline diagnostics - CBC, serum chemistry, urinalysis, coagulation profiles, imaging (radiographs, ultrasound), typically performed before toxicological testing.

In toxicology case formulation, what are key history components to obtain?

- Signalment.

- Clinical signs with onset and progression.

- Presence of other affected or exposed animals.

- Indoor vs. outdoor status and access to houseplants, gardens, or landscaping.

- Medical history.

- Diet, water source, and supplement use.

Why should baseline diagnostics be performed before toxicological testing?

They help assess the patient's overall condition, identify organ involvement, and narrow the differential list, guiding targeted toxicological analyses rather than indiscriminate testing.

Why is additional information required before requesting toxicological analyses?

Because:

- History may be incomplete, inaccurate, or intentionally withheld.

- Owners may not volunteer all relevant details.

- Avoid jumping to conclusions, even in seemingly obvious cases.

- Repeated, varied questioning can uncover critical missing data.

Q: What are the five factors toxicological rule-outs are based on?

1. History.

2. Physical or postmortem examination.

3. Baseline diagnostic tests.

4. Environmental examination.

5. Toxicological analyses.

In large animal toxicology cases, what additional examination is recommended beyond the patient assessment?

Environmental examination - evaluating the surroundings for possible toxic exposures.

Why might the same important question be asked multiple times in different ways during toxicology history-taking?

To elicit overlooked or withheld information, detect inconsistencies, and ensure a complete, accurate history.

In antemortem toxicology sampling, what general principle should be followed?

Collect everything you can easily access in the live animal, using appropriate sample types and handling protocols.

What specific samples are recommended for antemortem toxicological testing?

- Blood (whole blood and serum - spin and separate serum).

- Urine.

- Feces.

- Vomit or gastric lavage fluid.

- Hair (if topical exposure suspected).

Why is serum separation important in toxicology testing?

It prevents cellular metabolism or hemolysis from altering analyte concentrations, improving accuracy of results.

Why are "swabs" generally insufficient for toxicology testing?

They provide too little sample volume for most analytical methods.

Before submitting antemortem samples, what is recommended regarding quantity and type?

Call the lab or check its website for specific collection requirements.

In postmortem toxicology, what is the overarching sampling principle?

Collect everything and collect a lot - every organ, fluids, and relevant environmental or surface samples.

Which organs should be collected for postmortem toxicology?

Liver, kidney, brain, heart, skeletal muscle, fat, and any other organ potentially affected.

Which fluids should be collected postmortem for toxicology?

Urine, heart blood, and ocular fluid.

Which GI contents should be collected postmortem for toxicology?

Stomach or rumen contents, cecal or intestinal contents, feces, and crop or gizzard contents (in birds).

When should skin or hair be collected in postmortem sampling?

If topical exposure is suspected.