Calcium oxalate crystals found in urine in poisoning due to: (PGI June 2007)
**Core Concept**
Calcium oxalate crystals are found in urine due to the precipitation of calcium ions and oxalate ions. This occurs in conditions where there is an excess of oxalate ions, such as in ethylene glycol poisoning, or in conditions where there is a decreased ability to excrete oxalate ions, such as in kidney failure.
**Why the Correct Answer is Right**
In ethylene glycol poisoning, the metabolism of ethylene glycol to glycolic acid and oxalic acid leads to an accumulation of oxalate ions in the body. Oxalate ions combine with calcium ions to form calcium oxalate crystals, which are then excreted in the urine. This is a key diagnostic feature of ethylene glycol poisoning. The presence of calcium oxalate crystals in the urine is a strong indication of ethylene glycol poisoning, and is often used as a diagnostic criterion.
**Why Each Wrong Option is Incorrect**
**Option A:** This option is incorrect because the formation of calcium oxalate crystals is not a direct result of salicylate poisoning. While salicylate poisoning can cause kidney damage, it is not typically associated with the formation of calcium oxalate crystals in the urine.
**Option B:** This option is incorrect because the formation of calcium oxalate crystals is not a direct result of acetaminophen poisoning. While acetaminophen poisoning can cause liver damage, it is not typically associated with the formation of calcium oxalate crystals in the urine.
**Option C:** This option is incorrect because the formation of calcium oxalate crystals is not a direct result of aspirin poisoning. While aspirin poisoning can cause kidney damage, it is not typically associated with the formation of calcium oxalate crystals in the urine.
**Clinical Pearl / High-Yield Fact**
The presence of calcium oxalate crystals in the urine is a specific and sensitive indicator of ethylene glycol poisoning, and should be considered in any patient with a history of exposure to ethylene glycol. This is a key diagnostic feature of ethylene glycol poisoning, and is often used as a diagnostic criterion.
**Correct Answer:** C. Ethylene glycol poisoning.