The role of the laboratory in the investigation of solvent abuse

Inhalant abuse in pregnancy

Information from a variety of sources suggests the possibility of adverse effects of maternal inhalant abuse, although a well-controlled, prospective study in this area has not been conducted. One source of this concern is the data from occupational exposure to some of the abused solvents, specifically toluene and TCE, with numerous reports suggesting increased spontaneous abortion and fetal malformations. There are also data suggesting decreased fertility and an increased risk for spontaneous abortion in health care workers exposed to nitrous oxide. The relevance of these studies to problems of inhalant abuse is not clear. Although the chemicals involved are the same, there are many differences in the exposure parameters, the populations exposed, and the types of associated risk factors. Nonetheless, there are more than 100 cases reported in the literature of children born to solvent-abusing mothers. Many of these children were small at birth, and some have craniofacial abnormalities not unlike that seen in children with FAS. In the few studies reporting the findings of follow-up in these children, some evidence has been obtained for retardation in growth and development and for residual deficits in cognitive, speech, and motor skills. Clearly, more research is needed to rule out the concomitant risk factors and to identify specific chemicals and patterns of use associated with adverse effects. Animal studies provide more direct evidence that prenatal exposure to toluene or TCE can produce reduced birth weights, occasional skeletal abnormalities, and delayed neurobehavioral development, even under conditions designed to mimic inhalant abuse patterns. Additional research is needed to identify other chemicals with adverse effects, critical periods of exposure, effects of combinations of inhalants, or interactions with drugs of abuse. The research literature seems sufficient to alert clinicians to possible problems in patients who abuse inhalants while pregnant. Diagnosis and good prenatal care for these women are important. The evidence for neonatal withdrawal is limited at this time; however, infants born to women who have recently used inhalants should be observed carefully for an alcohol-like withdrawal syndrome. Although it is not possible to link a specific birth defect or developmental problem in the child of an inhalant abuser to prenatal exposure to a specific chemical, it is clear that inhalant abuse and its associated lifestyle place children at increased risk. A wider appreciation of this is needed among health care professionals and the general public.

An evaluation of unleaded petrol as a harm reduction strategy for petrol sniffers in an aboriginal community

OBJECTIVE

In mid 1989, leaded petrol was replaced by unleaded petrol to reduce lead toxicity in petrol sniffers in Maningrida, a remote Aboriginal community in Northern Australia. RETROSPECTIVE REVIEWS: Hospital admissions between 1987 and 1992 due to petrol sniffing were compared for Maningrida and a community using only leaded petrol.

RESULTS

Admissions from Maningrida decreased significantly following introduction of unleaded petrol (chi 2 on 2df = 22.25, p < 0.001). Lead and hydrocarbon exposures were also compared for three groups from Maningrida (27 sniffers using only unleaded petrol; 15 exsniffers and 13 nonsniffers) and 24 individuals admitted to hospital for petrol sniffing related illness from other communities using only leaded petrol. Median blood lead levels for hospitalized sniffers (using only leaded petrol). Maningrida sniffers (using only unleaded petrol), exsniffers and nonsniffers were 5.06, 1.87, 1.24 and 0.17 microM/L respectively. There were significant differences between blood lead level, delta-aminolevulinic acid dehydratase activity, and free erythrocyte protoporphyrin for sniffers of leaded and unleaded petrol, whereas these indices were not significantly different for current sniffers and exsniffers in Maningrida. Hydrocarbons were only detectable in the blood of active sniffers (toluene < or = 0.5 micrograms/mL; benzene < or = 0.17 micrograms/mL blood; n-hexane not detected).

CONCLUSIONS

The elimination of tetraethyl lead from petrol resulted in a significant decrease in hospitalization of petrol sniffers.

Elevated serum creatine kinase (CK-MM) in petrol sniffers using leaded or unleaded fuel

This study examined blood lead and creatine kinase levels in a group of 24 Australian Aboriginal males admitted to the hospital for treatment of severe petrol sniffing related illness after using only leaded petrol and 27 sniffers, 16 ex-sniffers and 13 non-sniffers from an isolated Aboriginal community using only unleaded petrol. Creatine kinase levels (which were nearly all creatine kinase-skeletal muscle isoenzyme indicating skeletal muscle damage) were correlated with blood lead levels and were elevated in active sniffers of leaded petrol on admission to hospital but were also increased in those sniffing unleaded petrol in the remote community. After fourteen days in hospital, median creatine kinase levels of leaded petrol sniffers dropped rapidly to levels similar to those of ex-sniffers and non-sniffers while median blood lead levels decreased but still remained higher than the other three groups. The data suggest that elevated creatine kinase associated with petrol sniffing may be due to compounds in petrol other than the lead additives, possibly volatile hydrocarbon components. Elevated creatine kinase may be useful in detecting current petrol sniffing activity, particularly in locations using unleaded petrol.

Burns following cigarette lighter fluid abuse

Seven patients with burns associated with butane cigarette lighter fluid abuse, in a group setting within an enclosed space, are presented. In all patients there was a reluctance to admit that butane vapour was in use as an intoxicant immediately prior to the injury. It is obvious from the circumstances of these injuries that the hazardous nature of cigarette lighter fluid is not fully appreciated. Since the resultant injuries are usually minor (all patients recovered spontaneously with conservative management, the hospital stay averaging 2 days), it is probable that many more occur, but do not present to accident departments as the victims are wary of repercussions should they admit to intoxicant vapour abuse. In view of the medical sequelae that can follow butane inhalation, burns unit staff should be aware of the problems, their recognition and treatment.

Diagnosis and treatment of acute poisoning with volatile substances

1. The acute toxicity of many volatile compounds is similar, being more related to physical properties than to chemical structure. 2. Volatile substance abusers experiences euphoria and disinhibition but this may be followed by nausea and vomiting, dizziness, coughing and increased salivation; cardiac arrhythmias, convulsions, coma and death occur in severe cases. 3. Laboratory analysis of blood and urine samples collected up to 24 h post-exposure may be helpful if the diagnosis of volatile substance abuse is in doubt. 4. There is only a weak correlation between blood toluene and 1,1,1-trichloroethane concentrations and the clinical features of toxicity, possibly because of rapid initial tissue distribution and elimination. 5. Recovery normally occurs quickly once exposure has ceased but support for respiratory, renal or hepatic failure may be needed as well as treatment for cardiac arrhythmias. Therapy with intravenous acetylcysteine should be considered in cases of acute carbon tetrachloride poisoning.