By consuming in large quantities, which of the following alcohol causes blindness and even death ?

The correct answer is Methanol.

Key Points

• Methanol, also known as wood alcohol, is highly toxic when ingested in significant quantities.
• Consumption of methanol can cause serious health issues such as blindness, organ failure, and even death.
• Methanol is metabolized in the body to formaldehyde and formic acid, which are toxic to the optic nerve and central nervous system.
• The ingestion of as little as 10 mL of pure methanol can cause permanent blindness, while 30-240 mL can be fatal depending on individual susceptibility.
• Symptoms of methanol poisoning include headache, dizziness, nausea, blurred vision, and in severe cases, coma or death.

Additional Information

• Ethanol vs Methanol:
  • Ethanol is the type of alcohol found in alcoholic beverages and is safe for human consumption in moderate amounts.
  • Methanol is used in industrial applications such as antifreeze, fuel, and solvents, and is not safe for consumption.
• Mechanism of Toxicity:
  • When methanol is ingested, it is converted by the enzyme alcohol dehydrogenase into formaldehyde and then to formic acid.
  • Formic acid leads to acidosis (a drop in blood pH) and damages the optic nerve, causing blindness.
• Treatment of Methanol Poisoning:
  • Immediate treatment includes administration of ethanol or fomepizole to inhibit alcohol dehydrogenase and prevent the formation of toxic metabolites.
  • Supportive treatments like dialysis may also be required to remove methanol and formic acid from the bloodstream.
• Prevention:
  • Public awareness campaigns and strict regulations on methanol-containing products are essential to prevent accidental or intentional ingestion.
  • Proper labeling and storage of industrial methanol can help reduce accidental poisoning cases.