Q: Ethylene glycol intoxication causes Hypocalcemia or Hypercalcemia? (Choose one)

Answer:  Hypocalcemia

Ethylene glycol toxicity (anti freeze) causes hypocalcemia and usually starts occurring around 12 to 36 hours after ingestion. Ethylene glycol metabolized to oxalate and binds to calcium to form Calcium Oxalate crystals.

One of the clue almost always given in Critical Care Board exams is presence of envelope shaped Calcium Oxalate crystals in urine, though presence of it signifies pretty advance stage of toxicity.