Unusual D-lactic acid acidosis from propylene glycol metabolism in overdose.

Objective: To report a case of D-lactic acid acidosis owing to massive oral ingestion of propylene glycol.

Case report: A 72-year old man with known congestive failure was admitted to the ICU with encephalopathy. Twelve hours prior to admission he had erroneously ingested a large amount of propylene glycol (PG). The laboratory revealed high anion gap (anion gap = 27 meq/l) acidosis (arterial pH = 7.16) and an increased osmolal gap. Toxicological analysis revealed a low serum propylene glycol level. Biochemical analysis indicated that very high amounts of D-lactic acid (up to 110 mmol/l), but not of the usual type of L-lactic acid, were responsible for the metabolic acidosis. Hemodialysis was initiated and associated with a decline of both the acidosis and D-lactic acid levels. The patient regained conciousness.

Conclusion: Ingestion of massive doses of propylene glycol, previously not reported as a cause of D-lactic acidosis, should be added to the differential diagnosis of this rare condition.