T/F: Ethylene glycol is bitter, colorless, and odorless
FALSE--it is sweet (very palatable to animals!)
Everything else is true
What is the main source of toxicosis?
Ingestion of antifreeze
How common is poisoning in cats and dogs?
Very--2nd most common cause of fatal poisonings in animals (APCC)
What is the mortality rate from ethylene glycol toxicosis in dogs? When is it more common?
More cases in fall, winter, and spring in NA
T/F: Swine and poultry have been poisoned by ethylene glycol
What are the minimum lethal doses of the undiluted EG?
- Humans, cats = 1.4 ml/kg
- Dogs = 4.2-6.6 ml/kg
- Poultry = 7-8 ml/kg
Where is EG absorbed/distributed?
Rapidly absorbed from the GIT (food delays absorption)
Rapidly distributed to all tissues including CNS
What is the half-life of EG in dogs?
11 hours (shorter in cats)
What is EG metabolized to?
Toxic metabolites, mainly in the liver
How does EG get converted to glyoxilic acid? What does that metabolized to?
- 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
What does oxalic acid bind to? What forms?
Binds to serum Ca to form insoluble Ca oxalate crystals (monohydrate) and hypocalcemia
How long are metabolites present?
T/F: A small amount of EG is excreted unchanged in the urine w/in 24hrs
What is the mode of action for EG?
- Direct GI irritation
- Inc. serum osmolality (osmotic diuresis)
- CNS depression
What is the MoA of of EG toxic metabolites?
Mainly causes metabolic acidosis and acute renal failure
How does glycoaldehyde cause CNS dysfunction?
By inhibition of respiration, glucose metabolism, serotonin metabolism, and alteration of amine concentration
T/F: Ca oxalate deposition contributes to CNS damage
What mainly causes metabolic acidosis in EG toxicosis?
Mainly due to glycolic acid but also other acids
T/F: Most metabolites are cytotoxic to renal tubular epithelium