A 20-year-old mechanic is brought to the emergency room after his co-workers found him exiting the garage inebriated and confused hours earlier. On examination, he is disoriented, ataxic, and complains of nausea. A urine toxicology screen is negative and urinalysis reveals the rhomboid calcium oxalate crystals seen here.
This patient has ethylene glycol (antifreeze) poisoning, demonstrated by the envelope-shaped calcium oxalate crystals seen here. Fomepizole — which inhibits the formation of toxic metabolites — is the preferred treatment for ethylene glycol poisoning. Severely poisoned patients presenting with acidosis may also require hemodialysis.