Volatile substances
If anaesthesia is excluded, acute poisoning with volatile substances usually follows the deliberate inhalation of a gas or solvent vapour by a person who wishes to become intoxicated (‘glue sniffing’, solvent abuse, inhalant abuse, volatile substance abuse (VSA)). VSA has been defined as ‘The deliberate inhalation of a volatile substance (gas, aerosol propellants, solvents in glue and other solvents) to achieve a change in mental state’ (Field-Smith et al. 2007). Solvents from adhesives (notably toluene), certain print correcting fluids and thinners, hydrocarbons such as those found in cigarette lighter refills, halocarbon aerosol propellants and fire extinguishers, and anaesthetic gases are among the products and/or compounds that may be abused in this way (Table 4.1). Those who ingest, or even more rarely inject, solvents or solvent-containing products, and the victims of clinical, domestic and industrial accidents, may also be poisoned by volatile substances. In addition, chloroform, diethyl ether and other volatiles are still used occasion ally in the course of crimes such as rape and murder. Another volatile compound, chlorobutanol (chlorbutol), sometimes employed as a sedative, a plasticiser and a preservative, has been used in doping greyhounds. Isobutyl and isopentyl (‘amyl’) nitrites may also be inhaled to experience their vasodilator properties, sometimes by male homosexuals. Solvents and other abusable volatiles can produce dose-related central nervous system (CNS) effects similar to those of other sedative and hypnotic agents. Small doses can rapidly lead to euphoria and other behavioural disturbances that are similar to those caused by ethanol, and may also induce more profound effects such as delusions and hallucinations. Heightened sexual (self-) gratification may also be a feature, sometimes in association with partial asphyxia. Once exposure ceases, rapid recovery normally ensues – this process may take only a few minutes if a relatively volatile substance has been inhaled. Rapid recovery after exposure may be a factor in the continuing popularity of VSA among secondary school children (13–18 years of age, or thereabouts) in some countries. On the other hand, psychological dependence is common in chronic users, although withdrawal symptoms are rarely severe. VSA has now been reported from most parts of the world, mainly among adolescents, individuals who live in remote communities and those with occupational access to abusable volatiles (Flanagan and Ives 1994; Kozel et al.
1995). The prevalence of inhalant abuse has been increasing in the USA in recent years (Brouette and Anton 2001). In the UK, deaths due to VSA fell to their lowest annual total recorded in 2005 (Field-Smith et al. 2007); of the 45 deaths recorded, butane from all sources accounted for 80% of VSA deaths. The major risk associated with VSA is that of sudden death. In a long-term monitoring study carried out in the UK, with findings reported annually (Field-Smith et al., 2007), most sudden VSA-related deaths were attributed to ‘direct toxicity’, but deaths also occurred from ‘indi rect’ causes such as inhalation of vomit, asphyxia associated with use of a plastic bag, and trauma. These ‘indirect’ deaths were frequently associated with abuse of products that contain toluene, usually adhesives (glue). The deaths that were attributed to ‘direct toxicity’ were predominantly associated with abuse of liquefied petroleum gas (LPG) cigarette lighter refills. In a US study utilising data from the Toxic Exposure Surveillance System of the American Association of Poison Control Systems (1996–2001), petrol (gasoline) was iden tified as the most commonly abused substance and was responsible for the highest proportion of deaths (45%) associated with VSA (Spiller 2004). Chronic toxicity from exposure to volatile substances has also been described both in abusers and after occupational use of certain compounds. Chronic toxicity, such as lead poisoning from abuse of leaded petrol, may be especially prevalent in developing countries or societies (ethnic populations).
