Possible fatal hyperthermia involving drug abuse in a vehicle: case series

Major interplaying causes of heat stroke (HS) and fatal hyperthermia are climate, physical activity, artificial extreme ambient temperatures, confinement in a small compartment, and effects of drugs and chemicals, combined with predispositions and complications. A common and unfortunate cause of HS is vehicular hyperthermia (VH) death. Hyperthermia in a vehicle is a type of environmental thermal disorder, involving victim's susceptibility, confinement with restraint, and possible influences of drugs and poisons, including exhaust gas containing complex fumes, carbon dioxide and monoxide. Whereas VH typically occurs when babies or young children are being left unattended in parked vehicles in direct sunlight, it has been reported only anecdotally for adult subjects. Three cases of adult fatal VH will be herein presented. In each presented case the corpse was found enclosed in a vehicle on spring/summer days. During crime scene investigation (CSI) psychoactive substances were found near to the corpses leading to the suspect of a suicidal fatal drug intoxication. Basing on this misleading suspect in Case 2 and 3 a forensic expert was not charged for the CSI and a fatal VH was not suspected nor properly investigated. Later, a comprehensive autopsy, including biochemical and toxicological analyses, excluded a death related to natural causes, fatal intoxications, ketoacidosis and traumas. On the other hand, the reconstruction of the temperature, the humidity, the heat index and the related risk of HS allowed the diagnosis of fatal VH in all the reported cases. In particular, death occurred because of the long-lasting stay into a hot parked vehicle which was facilitated from self-administration of psychoactive drugs with related neuro-depression. This case series confirms that a comprehensive CSI followed by an autopsy including histology, biochemical and toxicological analysis remains mandatory in cases of forensic interest, as well as when a corpse is found enclosed in a vehicle. Anyway, sometimes the diagnosis of heat-related fatalities remains a medley of investigative and medicolegal observations.