Canis ISSN: 2398-2942

Ethylene glycol poisoning

Introduction

• One of the most common poisonings.
• Highly palatable, drunk willingly, especially if no other water sources available.
• Signs: vomiting, ataxia, polydipsia.
• Treatment: ethanol, supportive fluid therapy, 4-methyl pyrazole.
• Cause: antifreeze poisoning.
• Diagnosis: signs, history, urinalysis, serum chemistry, commercial test kit.
• Prognosis: guarded if delayed presentation.
  Follow the diagnostic tree for Evaluating Ataxia in Suspected Ethylene Glycol Toxicity Evaluating Ataxia in Suspected Ethylene Glycol Toxicity.

Pathogenesis

Etiology

• Antifreeze consumed as concentrated solution. (undiluted = 95% ethylene glycol, working solution in car radiator is 50%).
• Poisoning from drained radiator water.
• Malicious poisoning.

Pathophysiology

• Gastric irritant, metabolites are cytotoxic.
• Absorption slowed by presence of food in gut.

• Rapidly absorbed from GI tract and distributed in circulation.
• Metabolized in liver.
• Ethylene glycol → glycoaldehyde → glycolate → oxalate.
• Excreted via kidneys.
• Aldehydes cause central nervous system (CNS) toxicity.
• Oxalate crystal formation → renal tubular damage.
• Metabolites cytotoxic to renal tubular cells, also contribute to metabolic acidosis.
• LD50 2-6 mg/kg (3-5 ml/kg).

Timecourse

• Signs occur within 1 hour of ingestion, usually mild incoordination and ataxia. These resolve quickly.
• Urinary excretion evident between 6-48 h.
• 1-6 h CNS signs predominate.
• 12-24 h cardiopulmonary signs appear.
• 24-72 h oliguric renal failure.
• Onset is quicker with greater ingestions.

Diagnosis

Treatment

Outcomes