P40: A case report of persistent near-fatal anion gap acidosis due to a massive gamma-butyrolactone (GBL)/ethanol intoxication

Case We report a case of an intentional massive gamma-butyrolactone (GBL) intoxication, the precursor of the recreational drug gamma-hydroxybutyric acid (GHB), resulting in life-threatening metabolic acidosis (pH 6.5) with a highly increased anion- and osmolal gap. Rapid analysis using gas chromatography revealed no methanol nor ethylene glycol but a GHB plasma concentration of 4398 mg/L, far above the upper limit concentration found in fatalities attributed to GBL. Full recovery was established following supportive treatment including hemodialysis. This is the first report of GBL intoxication as a cause of high serum anion- and osmolal gap metabolic acidosis. Conclusions GHB/GBL is not a substance classically associated with high anion gap metabolic acidosis (HAGMA), but the finding of the massive GHB concentration was a direct result of the method used in this lab, allowing the simultaneous detection of several substances potentially causing HAGMA (P. Van Hee et al. , Clin. Chem. Lab. Med. 2004; 42(11):1341-1345). Classical ethylene glycol methods would not measure GHB and suitable GC-MS techniques for rapid detection of this illicit drug are not widely available. Here, we propose that GBL/GHB intoxication should be considered in the differential diagnosis of this acid-base disorder. In view of the persistent acidosis, hemodialysis was life-saving.