Chasing the dragon--neurological toxicity associated with inhalation of heroin vapour: case report

Heroin-associated death may be related to acute overdose of high-dose or pure ("Chinese white") heroin, complications of intravenous drug use such as infection with FUV or hepatitis C, violence or other causes. Heroin was a popular drug in the late 1960s and early 1970s;3 its use declined subsequently but is now making a resurgence. Although a lifetime prevalence of heroin use is reported in only 0.5% of the Canadian population, heroin use has been increasing in Toronto, Montreal and Calgary and is best documented in Vancouver.4 Recent editorials have focused on the need both for increased awareness and for clinical trials of methadone for treating heroin addicts.5-7 Heroin abuse has been growing in Canada and, combined with cocaine abuse, was the leading cause of death in men 30 to 44 years of age in 1993 in British Columbia.7 Though investigation of the original cohort of 47 patients from Amsterdam, including autopsy for 10 of them, toxicologic analysis of heroin samples, investigation of unaffected heroin addicts and testing of the effects of heroin vapour in animal models, failed to find a toxicologic cause of the leukoencephalopathy.2 The autopsies revealed severe changes in the white matter, termed vacoulating myelinopathy; this lesion was characterized by formation of vacoules in the oligodendroglia, resulting in spongiform degeneration. Although several additive substances were discovered in the heroin samples, none were known or shown to produce the histopathological change in the rat or the rabbit model. The authors speculated that an as-yet-- unidentified toxic substance is released when heroin is heated.2 One case involving a similar vacuolating myelinopathy of the brain was reported in association with intravenous heroin overdose.16 Similarly, one case of delayed spongiform leukoencephalopathy has been reported after multidrug overdose, but heroin was not implicated;17 the authors attributed their findings to cocaine. Perez and associates18 reported a case of acute leukoencephalopathy isolated to the cerebellum in the 2 1/2-year-old child of a heroin addict; the child's gastric contents, urine and delayed hair samples contained heroin. Therefore, inhalation of heroin pyrolysate may not be the sole way of acquiring this toxic leukoencephalopathy.