Ethylene glycol toxicosis

Question 1

T/F: Ethylene glycol is bitter, colorless, and odorless

Answer 1

FALSE–it is sweet (very palatable to animals!)

Everything else is true

Question 2

What is the main source of toxicosis?

Answer 2

Ingestion of antifreeze

Question 3

How common is poisoning in cats and dogs?

Answer 3

Very–2nd most common cause of fatal poisonings in animals (APCC)

Question 4

What is the mortality rate from ethylene glycol toxicosis in dogs? When is it more common?

Answer 4

59-70%

More cases in fall, winter, and spring in NA

Question 5

T/F: Swine and poultry have been poisoned by ethylene glycol

Answer 5

TRUE

Question 6

What are the minimum lethal doses of the undiluted EG?

Answer 6

• Humans, cats = 1.4 ml/kg
• Dogs = 4.2-6.6 ml/kg
• Poultry = 7-8 ml/kg

Question 7

Where is EG absorbed/distributed?

Answer 7

Rapidly absorbed from the GIT (food delays absorption)

Rapidly distributed to all tissues including CNS

Question 8

What is the half-life of EG in dogs?

Answer 8

11 hours (shorter in cats)

Question 9

What is EG metabolized to?

Answer 9

Toxic metabolites, mainly in the liver

Question 10

How does EG get converted to glyoxilic acid? What does that metabolized to?

Answer 10

• EG is oxidized by alcohol dehydrogenase to glycoaldehyde
• Glycoaldehyde is oxidized by aldehyde dehydrogenase to glycolic acid
• Glycolic acid is oxidized by aldehyde dehydrogenase to glyoxilic acid
• Glyoxilic acid is metabolized to oxalic acid, glycine, formic acid, hippuric acid, and benzoic acid

Question 11

What does oxalic acid bind to? What forms?

Answer 11

Binds to serum Ca to form insoluble Ca oxalate crystals (monohydrate) and hypocalcemia

Question 12

How long are metabolites present?

Answer 12

Several days

Question 13

T/F: A small amount of EG is excreted unchanged in the urine w/in 24hrs

Answer 13

TRUE

Question 14

What is the mode of action for EG?

Answer 14

• Direct GI irritation
• Inc. serum osmolality (osmotic diuresis)
• CNS depression

Question 15

What is the MoA of of EG toxic metabolites?

Answer 15

Mainly causes metabolic acidosis and acute renal failure

Question 16

How does glycoaldehyde cause CNS dysfunction?

Answer 16

By inhibition of respiration, glucose metabolism, serotonin metabolism, and alteration of amine concentration

Question 17

T/F: Ca oxalate deposition contributes to CNS damage

Answer 17

TRUE

Question 18

What mainly causes metabolic acidosis in EG toxicosis?

Answer 18

Mainly due to glycolic acid but also other acids

Question 19

T/F: Most metabolites are cytotoxic to renal tubular epithelium

Answer 19

TRUE