Two gaps too many, three clues too few? Do elevated osmolal and anion gaps with crystalluria always mean ethylene glycol poisoning?

A 60-year-old African-American man with a medical history significant for heavy alcohol abuse, hypertension, delirium tremens, nephrolithiasis and seizure disorder was brought to the hospital with altered mental status. He was found to have high anion gap metabolic acidosis with significantly elevated lactate along with an elevated osmolal gap and calcium oxalate crystals in his urine. With this combination of findings, ethylene glycol poisoning was high in the differential. This case report describes why ethylene glycol poisoning was not the diagnosis in this patient despite the presence of these three classic laboratory findings, therefore emphasising the fact that these findings should not be taken at face value because they can be seen collectively in a patient yet each have a different cause.