Toxicology: Lecture 1

Lecture 1

Intro

Poison

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

Poisonous

(of a substance) causing or capable of causing death or illness if taken into the body

Toxin

a poisonous substance that is a specific product of the metabolic activities o a living organism, is notably toxic when introduced into the tissues of another organism and is typically capable of anitbody formation

Toxic

(of a substance) containing or being poisonous material especially when capable of causing death or serious debilitation

Toxicant

Any toxic substance. Toxins can be poisonous and may be synthetic or naturally occurring

Different types of toxins can be found in

Air, soil, water, food

Venom

a toxic substance produced by some animals that is injected into prey or an enemy chiefly by biting or stinging and has an injurious or lethal effect broadly

Venom producing animal examples

snakes, scorpions, hymenopterans, cnidarians

"If you bite it and die it is_____"

Poision

"If it bites you and you die_______"

Venom

Toxicosis

pathologic condition caused by the action of a poison or toxin

Intoxication

the state of being intoxicated. In common use frequently refers to ethanol but "intoxication" is not for a specific cause. In medical and specific contents its best to specify cause "ethanol intoxication"

Poisoning

the action of administering poison to a living organism

Toxicity

The quality of being toxic or poisonus

Does natural equal non toxic?

NOPE

"Natural" "oranganic" and "Non artificial" tell you what about safety?

Nothing

Most of the toxic substances known to science are

Naturally occurring

The 7 most deadly (to humans) chemical substances are

1. Botulinum toxin A

2.Tetanus toxin A

3. Diptheria toxin

4.Dioxin

5. Muscarine

6. Bufotoxin

7. Sarin

Botulinum toxin A

From bactetrial clostridium botulinum

Tetanus toxin A

From bacteria- Colostridium tetani

Diptheria toxin

From bacteria- Corynebacterium diptheriae

Dioxin

Manufactured

Muscarine

From mushrooms-Amanita muscaria

Bufotoxin

From a toad-genus bufo

Sarin

Manufactured

Hazard

something that has the potential to cause harm. Includes an element of magnitude. (ex mild dermal irritation vs melanoma) Could be physical trauma, chemical effect, infection, neoplasia etc

Risk

The likelihood a hazard will cause harm. Includes an element of probability (1 in 100,000?) over what timeframe?

Risk Equation

Hazard x Probability

Hazards include an element of __________ Risk includes and element of __________

1. Magnitude

2. Probability

Risk assesment

The systematic process of identifying, analyzing and evaluating potential hazards or risks that could cause harm determining if the risk is tolerable, not what could be done to reduce or eliminate it

A hazard is something that

Has the potential to harm you

A risk is the liklihood

Of a hazard causing harm

A DVM must put Hazard into

Context

Without context a hazard is

Meaningless

Why toxicological anaylisis?

We need to know what we are looking for and how to find it

Step 1 of toxilogical analysis

List toxilogical differentials

Toxilogical differentials are based on

Signalment

History

Clinical Signs

Other diagnostic information

Remember: Just because a toxic etiology is on your differential list__________________

Doesnt mean that it is necessarily the cause

Step 2 of Toxiological Analysis

Obtain appropriate samples

Different toxins are detectable in different

Matrices

When in doubt taking a sample....

Save it and ask D-lab what they need

Step 3 of Toxicology Analysis

Determine appropriate extraction technique

Appropriate extraction is usually done by D lab but they rely on you to

Collect, handle, and preserve necessary samples

Step 4: Toxicology analysis

Determine appropriate analysis (ex: microscopy, UV/visible spectroscopy, liquid/gas chromotography etc)

Step 5 toxicology anaylisis

Interpret results:

Qualitative vs quantitative

Clinical significance

Many Toxiological diagnoses are based on

History

Analysis is often ________ rather than __________

Confirmatory, Diagnostic

What does history consist of?

Signalment

Signs, onset, progression

Other animals: affected/ exposed

Indoor/outdoor: Houseplants/ garden/ landscape

Medical history

Food/Water/supplements

Tips for taking history

Do not assume

Do not jump to conclusions

Ask important questions several times in different ways if necessary

Examination

Physical exam, postmoretem exam

Did your exam findings fit the hx?

Baseline dianostics: Minimum database

May include

CBC, serum, chemistry

+/- urinalysis

+/-coagulative profile

Radiographs, ultrasound

Usually do baseline diagnositcs____________ specific toxilogical testing

BEFORE

Postmoretem Sampling

Antemoretem Sampling

Everything you can easily reach in a live animal

Examples of Antemoretem sampling

Blood

Whole blood and serum (spin and separate serum)

Urine

Feces

Vomit/gastric lavage

Hair in cases of topical exposure

Are swabs enough for most tox testing?

No

Collecting Postmoretem samples for tox testing

Collect everything and lots of it

Examples of postmoretem samples

Every organ: liver,kidney, brain, heart etc

Fluids: Urine blood from heart, aq fluid

GI contents: Stomach or rumen contents, cecal or intestinal contents, feces crop or gizzard contents

Skin/hair if suspect a topical exposure

Environmental exam

Mostly in LA cases, you have to ask questions in most sA

DAMNIT V

D: degenerative developmental

A: Anatomic

M: Metabolic

N: Neoplastic Nutritional

I: Infectious, inflammatory, immune mediated, idiopathic, latrogenic

T: Traumatic, toxic