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Ethylene Glycol Intoxication 315

early diagnosis in determining treatment • Activated charcoal 1-2 g/kg PO once: binds Recommended Monitoring
approach poorly but may be given if asymptomatic; Intensive early monitoring of respiratory rate,
VetBooks.ir ○ Normal osmole gap: 5-10 mOsm/kg (dogs • Interrupt conversion to toxic metabolites (BUN, creatinine), and urine production (ins Diseases and Disorders
will make EG tests false-positive.
• Serum osmolality; requires colloid osmometer
electrolytes, acid-base status, renal function
with fomepizole (4-MP, 4-methylpyrazole)
and cats). Osmole gap = measured osmo-
and outs). If clinical signs of AKI develop, best
lality − calculated osmolality; measured
ability to perform dialysis.
minutes), 15 mg/kg slow IV at 12 and
osmolality is obtained with a colloid ○ Dog: 20 mg/kg slow IV infusion (15-20 to refer to 24-hour care facility, ideally with
osmometer, and calculated osmolality 24h, 5 mg/kg IV at 36h
is obtained from the following equation ○ Cats < 3 hours after ingestion: 125 mg/ PROGNOSIS & OUTCOME
using values from the serum biochemistry kg slow IV infusion (15-30 minutes),
+
+
profile: 2 × ([Na ] + [K ]) + BUN (mg/ 31.25 mg/kg at 12, 24, 36h • Dogs: fair to good with intensive intervention
dL)/2.8 + glucose (mg/dL)/18. ○ Must be compounded as Antizol-Vet is within 8-12 hours of ingestion; prognosis
○ >20 mOsm/kg strongly suggests EG no longer commercially available worsens if clinical signs of AKI are appar-
intoxication; parallels EG blood level; • Or interrupt conversion to toxic metabolites ent at presentation and/or a large dose was
significant increase within 1 hour of with 7% ethanol solution in 5% dextrose ingested.
exposure or 0.9% saline • Cats: guarded to poor in any animal showing
• Anion gap (calculated from serum bio- ○ Commonly, Everclear (190 proof, or 95% clinical signs; intensive intervention (inter-
−
+
+
chemistry profile: ([Na ] + [K ]) − ([Cl ] ethanol) or plain vodka (80 proof, or 40% ruption of metabolism with high doses of
−
+ [HCO 3 ]) ethanol) is used as ethanol source (divide the fomepizole, dialysis, acid-base management)
○ Normal anion gap: 10-25 mEq/L (dogs proof by 2 to get the ethanol percentage). within 3 hours of exposure can prove
and cats) ○ To make a bag of fluids plus ethanol for successful.
○ >25 mEq/L can occur with EG infusion: (7%/ethanol %) × mL of fluids
intoxication = mL of ethanol. For example, if using PEARLS & CONSIDERATIONS
○ May note change by 3 hours but may vodka (7%/40%) × 1000 mL = 175 mL.
require 6 hours; is therefore less preferred Therefore, remove 175 mL of dextrose/ Comments
as an early diagnostic tool saline from a 1-L bag, and add 175 mL • Progression of irreversible, life-threatening
• Ultrasound: increased renal cortical echo- of vodka. effects from EG is rapid (hours), and
genicity at 4-6 hours; late in the course, ○ Loading dose: 8.6 mL/kg slow IV of the evaluation and treatment are urgent, even
halo sign indicative of anuria and grave solution in animals without overt clinical signs.
prognosis ○ Maintenance dose: 1.43-2.86 mL/kg/h • “Safe antifreeze” contains propylene glycol,
○ Many normal, healthy cats have diffuse constant-rate infusion (CRI) to effect which is less toxic compared to EG; much
hyperechogenicity of renal cortices (avoid ○ Duration of infusion: approximately 48 less risk of renal injury. Dogs need to ingest
overinterpretation). hours (5-7 times the half-life of EG) three or four times more propylene glycol
• Renal calcium level in postmortem tissue ○ Dogs treated with ethanol starting at 3 than EG to develop clinical signs.
sample hours after ingestion of EG excrete 80% • Use of injectable medications (diazepam),
of EG intact. or commercial preparations of activated
TREATMENT • Hemodialysis (more effective) or peritoneal charcoal before using EG test kits can give
dialysis while on ethanol or fomepizole. a false-positive result due to their propylene
Treatment Overview Immediate dialysis of any patient showing glycol, glycerol, and/or sorbitol content.
• EG toxicosis is a medical emergency. Due to clinical signs of intoxication tends to increase
rapid progression and irreversibility of renal the survival rate. Prevention
lesions, any patient suspected of consuming • Crystalloids: high infusion rates required to Keep animals indoors and not in the garage,
EG should be tested and treated unless/until correct severe dehydration and hypoperfusion. especially in freezing temperatures (frozen water
exposure has been ruled out. Must use great caution in case oliguria/anuria sources but antifreeze remains as liquid).
• The greatest window of opportunity for develops to avoid overhydration (p. 23)
intervention is < 8-12 hours after expo- • Acid-base and fluid volume management is Technician Tips
sure in dogs, < 2 hours after exposure critical to survival. • Human hospital laboratory may be able to
in cats. ○ Sodium bicarbonate as needed for meta- detect and quantify EG.
• Empirical treatment with fomepizole or bolic acidosis • Antifreeze (EG) usually is fluorescent green,
ethanol is indicated if the index of suspi- • Provide cofactors for metabolism of toxic viscous (like light syrup), and has no volatile
cion is high and a confirmatory test is not compounds odor; windshield washer fluid (not EG) is
immediately available. ○ Pyridoxine 1-2 mg/kg IV q 6h translucent blue, pungent (volatile odor),
• Emesis induction and administration of ○ Thiamine 50 mg slow IV q 6h and nonviscous (like water).
activated charcoal can be considered in • For animal with oliguria/anuria, euthanasia
asymptomatic cases presented within 1 hour is a reasonable consideration. Client Education
of exposure. Confirmed cases should receive • Lock antifreeze containers away from
fomepizole or ethanol and be hospitalized for Chronic Treatment chewing dogs.
management of acid-base abnormalities, fluid Dialysis to allow regeneration of damaged • Use cat litter to clean up spills and leaks.
diuresis for renal protection, and supportive tubular basement membrane; recovery may • About 1 tsp (5 mL) of EG is potentially
care. take many weeks lethal to an adult cat.
Acute General Treatment Possible Complications SUGGESTED READING
• Induction of vomiting (pp. 1087 and 1188): • Complications of AKI, including acute Thrall MA, et al: Ethylene glycol. In Peterson ME, et
helpful within 30-60 minutes; indicated if respiratory distress syndrome, pulmonary al, editors: Small animal toxicology, ed 3, St. Louis,
patient is a good risk. Some clinicians precede edema, seizures, and death 2013, Saunders Elsevier, pp 551-567.
this by very rapidly feeding a tasty meal to • Chronic renal compromise; depends on AUTHOR & EDITOR: Tina Wismer, DVM, MS, DABVT,
provide a substrate for the vomiting if the degree of insult and response to intensive DABT
pet has an otherwise empty stomach. treatment

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