Household products: Ethylene glycol (antifreeze) Flashcards
Uses of Ethylene glycol
antifreeze
MoA ethylene glycol
Ethylene glycol itself:
Direct GI irritation
Increased serum osmolality (osmotic diuresis)
CNS depression
Toxic metabolites:
Mainly cause metabolic acidosis & acute renal failure
CS of ethylene glycol
Early signs (30min-12h) post ingestion
nausea/vomiting, anorexia, CNS depression, ataxia, incoordination, hypothermia,
muscle fasciculations, tachycardia, tachypnea, polyuria, polydipsia, dehydration, coma, and death
Cats are markedly depressed and do not usually show polydipsia
Late Signs (24-72h PI dogs, 12-24h PI cats) for survivors of acute phase
oliguric renal failure
vomiting, anorexia, depression, severe lethargy, coma, seizures, oliguria and renal pain
Anuria 72-96h PI
Stages are of shorter duration in cats
Early signs may not be noticed by owners
Lab Dx of ethylene glycol
Chem: Anion gaps of more than 40-50mEg/L typical of EG
UA: calcium oxalate (monohydrate) crystals may be seen in urine sediment by 3h PI in the cat and 6h PI in the dog
Chemical analysis kits: Kacey™ EG test kit: - False positive can result from propylene glycol, mannitol, sorbitol, glycerol & ethanol.
Catachem Ethylene Glycol test - NO false positive with ethanol
Tx for ethylene glycol
Specific anitidotes
Inhibitors of alcohol dehydrogenase
Fomepizole (4-methyl-pyrazole, 4-MP) Antizol-Vet®
Generally no adverse effects
higher dose may be required to effectively treat cats
Ethanol 20%
Supportive therapy
Fluid therapy
Toxicokinetics of EG tox
Lethal synthesis
Ethylene glycol → glycoaldehyde → glycolic acid →glyoxylic acid ⇒oxalic acid
How do the products of EG metabolism play the bad guys?
CaOx crystals prcipitate in bloo clogging renal microcirculation causing acute tubular necrosis
Oxalic Acid responsible for nephrotoxicity, chelates Ca in blood to form CaOx
Px for EG
Early treatment (e.g. Fomepizole (4-MP) within 5-8hr PI) has good prognosis
Potentially shorter (3h) for cats
However once azotemic the prognosis is grave
