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There are three distinct stages in the development of signs and symptoms of ethylene glycol; neurologic abnormalities, cardiopulmonary dysfunction, and finally renal dysfunction Serum osmolality can be normal or elevated and is usually highest within the first several hours after ingestion.
The can be simultaneous presentation of an increase in the serum osmolal gap and high anion gap metabolic acidosis , however as more ethylene glycol is metabolized, serum osmolality will fall, and the serum anion gap will remain elevated or rise further. In some cases, both serum osmolality and the serum bicarbonate and anion gap can be normal, the only remnant of the disorder being the finding of calcium oxalate crystals on pathologic examination of the tissues.