Critical clue to ethylene glycol poisoning.

The authors report the case of a man 49 years of age with near-fatal ethylene glycol poisoning. Detection of calcium oxalate monohydrate crystals in the urine was the only real-time confirmation of the diagnosis. The case illustrates that, if the toxin has already been metabolized, familiarity with the appearance and significance of this unusual form of calcium oxalate crystal may be the key to an accurate diagnosis.