A person who has drunk the anti-freeze of his car is likely to have –
**Core Concept**
The toxic compound in anti-freeze, ethylene glycol, is metabolized by the enzyme alcohol dehydrogenase to form glycoaldehyde, which is then converted to oxalic acid by the enzyme lactate dehydrogenase. This process leads to metabolic acidosis, renal failure, and other systemic complications.
**Why the Correct Answer is Right**
When ingested, ethylene glycol is rapidly absorbed from the gastrointestinal tract and distributed throughout the body. The initial step in its metabolism is the conversion to glycoaldehyde by the enzyme alcohol dehydrogenase, which is present in the liver and other tissues. This is followed by the conversion to oxalic acid, which combines with calcium ions to form insoluble calcium oxalate crystals that precipitate in the kidneys, leading to renal failure. The systemic complications of ethylene glycol poisoning can be severe and include metabolic acidosis, seizures, and cardiac arrhythmias.
**Why Each Wrong Option is Incorrect**
**Option A:** None of the above - This option is incorrect because ethylene glycol poisoning is a well-documented cause of renal failure and metabolic acidosis.
**Option B:** Methanol poisoning - This option is incorrect because while methanol is also a toxic alcohol, the clinical presentation and metabolic pathway of ethylene glycol poisoning are distinct.
**Option C:** Hypoglycemia - This option is incorrect because ethylene glycol poisoning is not typically associated with hypoglycemia.
**Clinical Pearl / High-Yield Fact**
Fomepizole, an alcohol dehydrogenase inhibitor, is used as an antidote for ethylene glycol poisoning to prevent the formation of glycoaldehyde and subsequent oxalic acid.
**Correct Answer:** C.