LAUSR

1,1-Difluoroethane (DFE; HFC-152a) is a colorless and odorless gas often used as a propellant to remove dust from electronic equipment. Because DFE affects the central nervous system and produces a sense of euphoria, it is also often abused. We report a case of fatal, acute DFE poisoning in which the DFE concentrations in the blood and tissues were determined. A 30-year-old man with no known medical history was found dead in his room, lying on the floor and gripping an air-duster canister (AD-152A; Elecom, Osaka, Japan). Ten empty and two unused canisters were also found in the room. The man had been arrested in the past for substance use and abuse (paint thinner and Cannabis). Furthermore, he was known to have sold illicit substances for at least 2 years prior to his death and to lose consciousness at times after inhaling DFE in the restrooms of department stores. Because he had died of unnatural causes, a forensic autopsy was performed approximately 14 h after the body was discovered. The decedent was 171 cm tall and weighed 51.8 kg. Autopsy findings included fluid blood, petechial hemorrhage on the conjunctivas and epicardium, and congestive changes in the viscera that suggested sudden death. Neither injuries nor diseases were found macroscopically or microscopically. Body fluids and tissues were collected for DFE analysis. Quantitative analyses of DFE were conducted by gas chromatography/mass spectrometry (GC/MS) (Agilent 7890B and 5977A instruments; Agilent Technologies, Santa Clara, CA). Table 1 shows the concentrations of DFE detected in body fluids and tissues. Screening for toxicologic substances by GC/MS (GCMS-QP2010; Shimadzu, Kyoto, Japan) with the SHIMADZU GC/MS Forensic Toxicological Database revealed no other toxicologic substances in the blood. No alcohol was detected in the heart blood by GC (GC-14B; Shimadzu). Given the findings from the autopsy and toxicological analyses and the scene described by the police, the cause of death was determined to be acute DFE poisoning and the estimated the time of death to be 4–5 days prior to the autopsy. To our knowledge, 47 fatal DFE poisonings have been reported since 2004. Among the 15 cases in which DFE blood concentrations were noted, nine were DFE-only poisoning cases in which the DFE concentration in the heart blood ranged from 99.2 to 430.0 mg/ml (mean, 225.3 mg/ml) [1–5]. In our case, the DFE heart blood concentration was 81 mg/ml, a lower value than those previously reported in fatal DFE-only poisonings. According to the autopsy and histopathologic examination findings, the mechanism of death was determined to be fatal arrhythmia. The lethal mechanism was considered to involve DFE-induced sensitization of the myocardium to catecholamines, which may lead to fatal arrhythmia [1]. The measured DFE concentrations in the blood and various tissues may help in the evaluation of further fatal DFE poisoning cases.