Ethylene Glycol Toxicity Flashcards
Where can ethylene glycol be found?
antifreeze
What are common exposure situations for pets?
car/boat/truck maint. where it spills, drips, or leaks
How much ethylene glycol is necessary to ingest to be considered life-threatening?
Cat: 1.5mL/kg
Dog: 4-6.5mL/kg
What breaks down ethylene glycol?
broken down into toxic metabolites by alcohol dehydrogenase in the liver
How does ethylene glycol affect the body?
- Glycolate affects the kidneys & CNS
- Oxalate affects the kidneys and can also precipitate into crystals within the tubules causing obstruction of tubules and thus decreased total urine output of affected nephron
- Both increase acid load in circulatory system leading to metabolic acidosis and toxicity of renal tubular cells
Stage 1
- how long
- CS
30min to 12hr post ingestion
- occurs before metabolism of ethylene glycol
- CNS signs of ataxia, lethargy due to direct cytotoxic effect of glycolate on neurons
- PU/PD b/c ethylene glycol draws water into circulatory system which stimulates kidneys to increase urinary output with compensatory PD
- Nausea/vomiting due to secondary stim of vomiting center and/or irritation of stomach by antifreeze
Stage 2
- duration
- CS
12-24hr post ingestion
-tachypnea & tachycardia due to metabolic acidosis developing
Stage 3
- duration
- CS
24-72hr (dog) or 12-24hr (cat) post ingestion
- acute kidney injury
- CS like vomiting, anorexia, oliguria, anuria
Changes to CBC
none
Changes to serum chem
- severe azotemia and hyperphosphatemia b/c kidneys can’t excrete urea, creatinine, and phosphorus like they should
- hypocalcemia due to calcium being tied up within the oxalate crystal formation
Changes to UA
- calcium oxalate crystaluria
- isosthenuric due to renal tubule function decreasing
Are there any special tests to confirm ethylene glycol toxicity?
Yes, but must be done within 12hrs of ingestion to avoid false positive
What technique is used to minimize absorption of ethylene glycol? When is it used?
- do if P seen within 2-4hr of ingestion
- induce vomiting immediately
- once stomach is empty, lavage/flush with water and administer activated charcoal
- activated charcoal absorbs the ethylene glycol before it is absorbed into the body; excreted as a nontoxic compound in feces
What substance may be administered to inhibit the metabolism of ethylene glycol? When does it need to be given?
- within 24hr of ingestion
- 4-methylpyrazole in dogs
- ethanol in cats
Why is inhibition of alcohol dehydrogenase important?
it stops the enzyme from converting ethylene glycol into toxic metabolites
