A 31‐year‐old man with bipolar disorder presented with nausea, vomiting, abdominal pain, and blurry vision several hours after consuming antifreeze and alcohol in a suicide attempt. He was afebrile with a heart rate of 132 and respiratory rate of 18, but otherwise normal vital signs. He was somnolent, with clear lungs and normal cardiac exam. Cranial nerves, reflexes and coordination were all normal. He had no nystagmus, normal visual fields, and 20/20 vision bilaterally and fundoscopic exam was normal. Laboratory testing revealed arterial pH 7.30, serum bicarbonate 25 mmol/L, anion gap of 10, osmolar gap of 42 mOsm/kg, ethylene glycol level of 127 mg/dL, and ethanol level of 75 mg/dL. Treatment for toxic alcohol ingestion was initiated with fomepizole and intravenous bicarbonated fluids. Hemodialysis was initiated but subsequently discontinued when his methanol level returned to negative. His ethylene glycol level declined to 19 mg/dL over the following 36 hours, and his osmolar gap closed.
Ingestion of ethylene glycol and methanol, intentional or accidental, are uncommon but cause severe morbidity and mortality if not rapidly identified and treated, making therapeutic knowledge of these poisonings important to the practicing hospitalist. Accumulation of metabolites, glycolic acid, and oxalic acid from ethylene glycol and formic acid from methanol, are responsible for the toxicity in these ingestions. Therapy is aimed at either blocking metabolite formation via competitive (ethanol) or direct (fomepizole) inhibition of alcohol dehydrogenase in the liver or direct removal of metabolites via hemodialysis. Triage to antidiuretic hormone (ADH) inhibition versus hemodialysis should be made efficiently, as delay in treatment increases morbidity. Among ADH inhibitors, fomepizole is considered first‐line, as ethanol administration requires monitoring of blood concentration, causes inebriation, and risks liver toxicity, pancreatitis, and hypoglycemia. Indications for hemodialysis include severe or refractory metabolic acidosis, deteriorating vital signs, renal failure in ethylene glycol poisoning, and visual disturbances in methanol poisoning. Hemodialysis to shorten treatment duration in high‐grade poisoning is debated; the risks of this invasive therapy should be considered, as fomepizole cost has been reduced by the introduction of generics. Normal visual exam in our patient and negative methanol level voided the need for hemodialysis.
In ethylene glycol and methanol poisoning, treatment with fomepizole is preferred over ethanol, and hemodialysis can be reserved for refractory acidosis, renal failure, or visual impairment.
S. Hunt ‐ none
To cite this abstract:Hunt S. Antidotes to Antifreeze. Abstract published at Hospital Medicine 2011, May 10-13, Dallas, Texas. Abstract 298. Journal of Hospital Medicine. 2011; 6 (suppl 2). https://www.shmabstracts.com/abstract/antidotes-to-antifreeze/. Accessed July 16, 2019.