Unusual findings of isopropanol and chlorhexidine in a 4-month infant: a case of postmortem contamination linked to an inappropriate disinfection procedure.

A 4-month-old infant was found in cardiorespiratory arrest in his cot at the home of his childminder. The child's cardiac blood and gastric contents, taken during a body examination, were sent to us to investigate the cause of death in the context of sudden unexpected infant death. Alcohols (ethanol, methanol, acetone and isopropanol) were determined by gas chromatography-flame ionization detection (GC-FID), a broad screening was performed by high-performance liquid chromatography coupled with diode array detection (HPLC-DAD), gas chromatography-mass spectrometry (GC-MS) and a targeted screening of drugs and narcotics by liquid chromatography-tandem mass spectrometry (LC-MS/MS). Chlorhexidine was determined by LC-MS/MS. The child showed no symptoms in the days preceding his death. The autopsy concluded that death was linked to an asphyxia mechanism. Only isopropanol at a concentration of 23 mg/dL was found in the cardiac blood sample taken during the body examination. However, it was absent from the gastric contents. After discussion with the doctor, prior to external examination of the body, the child's skin and tubes were decontaminated by spraying a product containing 2% chlorhexidine and 70% isopropanol on the puncture area. A specific test for chlorhexidine was then carried out, revealing a concentration of 879 ng/mL. The concomitant presence of isopropanol and chlorhexidine makes the hypothesis of contamination of the sample by the disinfectant plausible. A second tube of peripheral blood, this time taken during the autopsy, was sent to us. This blood sample tested negative for alcohols and chlorhexidine, confirming the contamination of the first sample by the disinfectant.