Toxic Alcohol Poisoning

Published on 07/03/2015 by admin

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Last modified 07/03/2015

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Chapter 80 Toxic Alcohol Poisoning

Aaron B. Skolnik, MD , Susan R. Wilcox, MD

1 What are the compounds commonly referred to as the toxic alcohols?

Typically, the term toxic alcohols includes isopropanol, methanol, and ethylene glycol. Ethanol, of course, may also be toxic.

2 What household or commercial products commonly contain toxic alcohols?

Isopropanol (or isopropyl alcohol) is most commonly sold as rubbing alcohol, in a 70% solution. It can also be found in antifreezes, glass cleaners, jewelry cleaner, stain removers, deicers, household disinfectants, and hand sanitizers.

Methanol can be found in windshield washer fluid, antifreeze, copy machine fluid, canned fuel (Sterno), and some solvents. Perhaps most famously, methanol is a frequent contaminant in illicitly distilled alcoholic beverages—hence the term moonshine blindness, originating from methanol retinal toxicity.

Ethylene glycol is often the main ingredient in automobile antifreeze and is sometimes used as a solvent.

3 What are potentially lethal doses of isopropanol, methanol, and ethylene glycol?

Isopropanol ingestion of 150 to 250 mL can be lethal because of central nervous system (CNS) and myocardial depression.

The reported lethal dose of methanol is 1.2 mL/kg; however, as little as 30 mL (6 teaspoons) may cause permanent vision impairment.

The lethal dose of ethylene glycol in untreated patients varies, but 100 mL is a common conservative approximation.

4 What are the mechanisms of toxicity for isopropanol?

Isopropanol is estimated to be twice as intoxicating by volume as ethanol. It is a CNS depressant and may cause peripheral vasodilation, myocardial depression, and subsequent shock at high doses. It is metabolized by alcohol dehydrogenase (ADH) to acetone, which appears to contribute to further CNS depression. Isopropanol is extremely irritating to the gastric mucosa and classically causes severe gastritis, which may be hemorrhagic.

5 What are the mechanisms of toxicity for methanol?

Methanol is first metabolized by ADH to formaldehyde, which is then rapidly converted to formic acid by aldehyde dehydrogenase. Formic acid inhibits mitochondrial electron transport, leading to acidemia and production of reactive species. It also depletes glutathione, which is an endogenous antioxidant. The combination of these effects leaves cells that are under significant oxidative stress such as those in the retina and putamen, exposed to oxidant cytotoxicity.

6 What are the mechanisms of toxicity for ethylene glycol?

Ethylene glycol is metabolized to toxic glycolic acid, glyoxylic acid, oxalic acid, and several other minor metabolites. Oxalic acid precipitates with calcium into calcium oxalate crystals. In addition to causing hypocalcemia, deposition of oxalate in the renal tubules and other tissues causes cell death. The resulting metabolic acidosis, renal failure, pulmonary edema, and cerebral injury contribute to mortality in these patients.

7 What are the signs and symptoms of toxic alcohol poisoning?

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