Lecture 8 Forensics in Diagnosis of Poisoning in Animals

Question 1

Veterinary Toxicology

Answer 1

-The Toxicology Section of the Animal Disease and Diagnostic Laboratory
-solves mysteries

Question 2

Necropsy

Answer 2

Animal autopsy

Question 3

Differentials (different causes of death) when there are no lesions found in a necropsy

Answer 3

Causes of sudden death in dogs with minimal lesions:
* Organophosphate/carbamate insecticides,
* Strychnine,
* Fluoroacetate (1080),
* Zinc phosphide,
* Garbage poisoning,
* Drugs of abuse (barbiturates, cocaine, amphetamines).

Question 4

What is needed to prove the cause of poisoning?

Answer 4

– 1) the clinical syndrome, including historical information, clinical signs, and
response to antidotal (atropine and 2-PAM for OPs) or appropriate therapy, are
consistent with the suspected toxicant,
– 2) pathological and/or clinical pathological findings are consistent with the
suspected toxicant,
– 3) there is a marker that indicates the biological effect of the suspected toxicant,
and
– 4) results of analytical testing confirm the presence of the suspected toxicant in
the tissues of the patient at a level consistent with poisoning.

Obtaining this set of facts requires coordination between
clients/owners, clinical veterinarians, and veterinary diagnosticians
(e.g., pathologists and toxicologists)

Question 5

Diagnostic medical lab members

Answer 5

-Serology
-Virology
-Bacteriology
-Histopathology
-Toxicology (contributes most)

Question 6

Lead poisoning in cattle sources:

Answer 6

-Batteries : Batteries in pasture, batteries in trash piles, batteries in burned trash piles
(soil), batteries ground up in feed mixers, etc.
, Cattle will seek it out and chew on it & eat

-Lead paint on buildings
-In trash piles in batteries and old containers
-Lead shot in ground and taken up by plants (probably not)

Question 7

Lead diagnosis:

Answer 7

-Detection of lead is in while blood, feces, urine, or ,milk with clinical signs
-May see laminar cortical necrosis in brains
-radiographic evidence of metal in GI tract

Question 8

Treatment for lead poisoning

Answer 8

-Metal chelator
-Ex) calcium disodium EDTA or DMSA

Question 9

Lead is stored where in the body?

Answer 9

-Lead goes from RBC to soft tissue and is deposited in bone
-Lead only leaves bone by osteolysis during periods of high calcium demand (pregnancy, calcium deficiency, egg laying) or times of acidosis (exercise, metabolic or resp. acidosis)

-Lead can cross placenta and be in milk
-lead can also be found in eggs

Question 10

Factors affecting toxicity of animals:

Answer 10

-Differences in Exposures
-Different species are exposed to different toxicants
-Different species have access to different things
-Behavioral differences

Question 11

Behavior differences:

Answer 11

For example: Humans vs Dogs and Cats
-Humans have acid base ingestion
-Humans drink liquids by creating a vacuum and sucking liquid (can lead to oral and esophageal burns

-Dogs and cats lap up liquids- can cause chemical burns on tongue and lips
-No reports of esophageal strictures in dogs or cats

Question 12

Physiological differences:

Answer 12

(Includes differences in metabolism)
▪ Species (comparative toxicology)
▪ Genetic (species or individual differences, ex: copper)
▪ Individual variation
▪ Age of the animal
▪ Female or male
▪ Pregnancy
▪ Lactation
▪ Disease conditions
▪ Nutritional status

Question 13

Species differences in metabolism

Answer 13

• Cats are more sensitive to acetaminophen toxicity
  -Cats deficient in glucuronyl transferase= Acetaminophen (APAP) toxicity
• Dogs slow in metabolizing theobromine = long t ½ = Chocolate toxicity
• Guinea pigs don’t demethylate bromethalin

Question 14

Treatment for cats when acetaminophen poisoning due to being deficient in:

Answer 14

Glucuronyltransferase deficient!
Treat by giving
Mucomyst (n-acetylcysteine)