["Ghost peak" in gas chromatography in a delirious woman with severe metabolic acidosis. Intoxication with an unknown substance?].

HISTORY AND CLINICAL FINDINGS

A 31-year-old female with known type 1 diabetes mellitus was referred because of symptomatic hyperglycemia. On admission she was delirious and impressed with marked Kussmaul breathing. All other vital signs were normal.

INVESTIGATIONS

Blood serum glucose concentration was 26.4 mmol/l. Arterial blood gas analysis revealed massive metabolic acidosis (pH 6.80) with an elevated anion gap (21 mmol/l) and a marginally increased osmolar gap (21,5 mOsm/l).

TREATMENT AND COURSE

Despite normalization of the serum glucose and acidemia after administration of normal saline, insulin and bicarbonate, the delirium persisted, and the possibility of an additional intoxication had to be considered. Serum headspace analysis for intoxication with solvents (gas chromatography) finally detected a "ghost peak", which could not be assigned to any established substance. The same peak was, however, found in a healthy subject's serum and was found to be a "toluene peak". Toluene is contained as "contaminator" in gels in blood collection tubes. The patient gradually regained consciousness and "merely" suffered from diabetic ketoacidosis associated with cocaine use.

CONCLUSION

The differential diagnosis of high anion gap metabolic acidosis includes among other reasons intoxications with different kinds of solvents. When looking for solvents in the serum when poisoning is suspected (headspace analysis), only blood collection tubes without gel (EDTA plasma) should be used, because all gels contain solvents (in this case toluene).