Tox Exam 2 Common Household Products Flashcards
Ethylene glycol uses?
antifreeze, coolant, industrial solvent, rust remover, color film processing fluid, snow globes, hydraulic brake fluid, motor oil, windshield deicing agents
Chemical properties of ethylene glycol?
soluble in water, sweet, colorless, odorless, lowers freezing point of water, rust inhibitor
T/F Ethylene glycol poisoning is the most common cause of fatal poisoning in animals.
FALSE. Number 2 cause!
What seasons are there more cases of ethylene glycol poisoning?
fall, winter, spring in NA
What species have ethylene glycol poisoning been reported in?
cats, dogs, swine poultry
What species has the lowest LD for ethylene glycol poisoning?
cats
T/F There is increased absorption of ethylene glycol in the stomach if there is food present.
FALSE. delayed absorption due to food.
Distribution of ethylene glycol?
ALL tissues, 1/2 life 11 hrs in dogs–shorter in cats
Metabolism of ethylene glycol?
to TOXIC metabolites mainly in liver.
oxidized by alcohol dehydrogenase to glycoaldehyde–oxidized by aldehyde dehydrogenase to glycolic acid–oxidized by aldehyde dehydrogenase to glyoxylic acid–metabolized to oxalic acid, glycine, formic acid, hippuric acid & benzoic acid
oxalic acid binds to Ca–forms insoluble Ca oxalate cystals (monohydrate)
Excretion of ethylene glycol?
small amount unchanged & Ca oxalate crystals in urine
MOA of ethylene glycol toxicity?
ethylene glycol itself–>direct GI irritation, osmotic diuresis, CNS depression
toxic metabolites–>metabolic acidosis, ARF, CNS dysfunction
MOA in CNS effects d/t ethylene glycol?
Glycoaldehyde causes CNS dysfunction by inhibition of respiration, glucose metabolism, serotonin metabolism & altered amine concentration.
Ca oxalate deposition contributes to CNS damage.
MOA in metabolic acidosis d/t ethylene glycol?
mainly d/t glycolic acid
MOA in acute renal failure d/t ethylene glycol?
Most metabolites are toxic to renal tube epi. Ca oxalate monohydrate crystals w/in tubules cause damage by altering cell structure/function–increasing ROS & mitochondrial dysfunction
How many stages are involved in ethylene glycol poisoning?
2–early and late stages
stages are of shorter duration in kitty cats
Describe early stage of ethylene glycol poisoning.
30 min-12 hr (d/t EG effects & metabolic acidosis)
nausea/V+, anorexia, CNS depression, ataxia, incoordination, hypothermia, muscle fasiculations, tachycardia, tachypnea, PU/PD, dehydration, coma, death
cats–markedly depressed & no PD signs
Describe late stage of ethylene glycol poisoning.
24-72 hr in dogs & 12-24 hr in cats
V+, anorexia, depression, severe lethargy, coma, seizures, oliguria, renal pain, anuria (72-96 hr)
Gross pathology of ethylene glycol poisoning?
hemorrhagic gastroenteritis, pulmonary edema, pale & swollen kidneys w/ gray or yellow streaks
Micro pathology of ethylene glycol poisoning?
yellow rosette shaped Ca oxalate crystals in kidney, urine, perivascular space in brain
Lab dx for ethylene glycol poisoning?
increased serum osmolality, increased anion gap, low USG, hypocalcemia, hyperglycemia, decreased blood pH
Differential diagnosis for ethylene glycol poisoning?
toxin induced renal failure-->cholecalciferol, aminoglycosides, amphotericin B, cisplatin, NSAIDs, methoxyflurane, easter lily & day lily in cats. infectious agents (lepto, pyelonephritis) obstructive uropathy
Treatment for ethylene glycol poisoning?
fomepizole, ethanol
MOA: competitively inhibit ADH (alcohol dehydrogenase)–inhibit formation of toxic metabolites
T/F Can use activated charcoal with oral ethanol to treat ethylene glycol poisoning.
FALSE–do not use activated charcoal if using oral ethanol
What can be given to enhance metabolism of glyoxylic acid to non-toxic metabolites?
thiamine & pyridoxine
What can be given to treat acidosis related to ethylene glycol poisoning?
sodium bicarb
What can be given to treat ARF related to ethylene glycol poisoning?
mannitol & hemodialysis
T/F Ethanol has negative side effects that are not seen with fomepizole–CNS depression, diuresis & hyperosmolarity.
TRUE! but fomepizole can cause tachypnea, salivation, trembling.
note: faster recovery with fomepizole.
T/F Need higher doses of fomepizole in dogs than in cats to be effective.
FALSE. may need higher doses in cats!
Prognosis in ethylene glycol poisoning?
once azotemic=prognosis is grave
early tx–dogs w/in 5-8 hrs & cats w/in 3 hrs=good prognosis
Propylene glycol uses?
antifreeze, coolants, deicing, semi-moist pet food, treatment of bovine ketosis
Propylene glycol chemical properties?
colorless, odorless, looks like mineral oil, miscible in alcohol & water, unpleasantly flavored
Cause of accidental administration to horses?
accidentally given instead of mineral oil
What species are susceptible to propylene glycol?
dogs, cats, cattle, horses
What species are most susceptible to propylene glycol?
cats
T/F Ethylene glycol is safer than propylene glycol.
FALSE
What is the acute oral LD of propylene glycol in dogs?
9 ml/kg
ADME of propylene glycol?
A=GI tract and inhalation
M=in the liver by alcohol dehydrogenase to lactaldehyde–then metabolized by aldehyde dehydrogenase to lactic acid (D&L isomers)–then to pyruvic acid
E=propylene glycol partly excreted unchanged in urine
T/F Lactic acid & pyruvic acid are normal constituents of the citric acid cycle.
TRUE
Difference between L-lactic acid & D-lactic acid?
L-lactic acid used by CAC & D-lactic acid not used readily–accumulates–increased concentrations may cause lactic acidosis
T/F Propylene glycol is metabolized into non-toxic metabolites, while ethylene glycol is metabolized into toxic metabolites.
TRUE!
Clinical signs of propylene glycol poisoning?
PU/PD (d/t osmotic diuresis), ataxia, CNS depression, heinz body anemia & muscle twitching in cats, D-lactic acid metabolite may cause encephalopathy & metabolic acidosis
Treatment of propylene glycol poisoning?
emetics, activated charcoal, IV fluids, bicarb
alcohol dehydrogenase inhibitors are not required
vit C & E do not prevent heinz body formation
Prognosis of propylene glycol poisoning?
Good!
