Inhalant abuse in pregnancy

Prenatal toluene exposure impairs performance in the Morris Water Maze in adolescent rats

Volatile organic solvent abuse continues to be a worldwide health problem, including the neurobehavioral teratogenic sequelae of toluene abuse during pregnancy. Although abuse levels of prenatal toluene exposure can lead to a Fetal Solvent Syndrome, there is little research examining these effects on memory. Consumption of toluene can have detrimental effects on the developing hippocampus which could lead to specific spatial learning and memory deficits. This study used a rat model to determine how prenatal exposure to abuse levels of toluene would affect performance in a spatial learning and memory task, the Morris Water Maze (MWM). Pregnant Sprague-Dawley rats were exposed to 0, 8000 or 12,000ppm (ppm) of toluene for 15min twice daily from gestation day 8 (GD8) through GD20. Male and female offspring (N=104) were observed in the MWM for 5days beginning on postnatal day (PN) 28 and again on PN44. While prenatal toluene-exposed animals did not differ in initial acquisition in the MWM, rats prenatally exposed to 12,000ppm toluene displayed performance deficits during a probe trial and in reversal learning on PN44. Overall, this study indicates that prenatal exposure to repeated inhaled abuse patterns of high concentrations of toluene can impair spatial memory function that persists into adolescence.

Environmental influences on reproductive health: the importance of chemical exposures

Chemical exposures during pregnancy can have a profound and life-long impact on human health. Because of the omnipresence of chemicals in our daily life, there is continuous contact with chemicals in food, water, air, and consumer products. Consequently, human biomonitoring studies show that pregnant women around the globe are exposed to a variety of chemicals. In this review we provide a summary of current data on maternal and fetal exposure, as well as health consequences from these exposures. We review several chemical classes, including polychlorinated biphenyls, perfluoroalkyl substances, polybrominated diphenyl ethers, phenols, phthalates, pesticides, and metals. Additionally, we discuss environmental disparities and vulnerable populations, and future research directions. We conclude by providing some recommendations for prevention of chemical exposure and its adverse reproductive health consequences.

Toluene disruption of the functions of L1 cell adhesion molecule at concentrations associated with occupational exposures

BACKGROUND

Prenatal toluene exposure can cause neurodevelopmental disabilities similar to fetal alcohol syndrome. Both share neuroanatomic pathologies similar to children with mutations in L1 cell adhesion molecule (L1). L1 mediates neurite outgrowth (NOG) via signaling through ERK1/2, which require trafficking of L1 through lipid rafts. Our objective is to determine if toluene inhibits L1-mediated NOG and toluene inhibits L1 signaling at concentrations achieved during occupational exposure.

METHODS

Concentrations of toluene reflective of blood concentrations achieved in solvent abusers and occupational settings are used. Cerebellar granule neurons (CGN) harvested from postnatal day 6 rat pups are plated on coverslips coated with poly-L-lysine (PLL) alone or PLL followed by laminin. L1 is added to the media of CGN plated on PLL alone. Toluene is added 2 h after plating. Cells are fixed at 24 h and neurite length is measured. ERK1/2 activation by L1 in CGN is analyzed by immunoblot.

RESULTS

Toluene significantly reduced mean neurite length of CGN exposed to L1 but not laminin. Toluene significantly reduced L1-mediated ERK1/2 phosphorylation.

CONCLUSION

Results suggest that toluene inhibits L1-lipid raft interactions at occupationally relevant concentrations and may lead to a fetal solvent spectrum disorder similar to fetal alcohol spectrum disorder.

Scintigraphic evaluation of renal functional damage in volatile substance abusers

OBJECTIVE

Volatile organic compounds can be maintained easily and can cause dependency. Volatile substance abuse may cause damage by affecting several systems. The aim of our study was to evaluate renal functional damage in volatile substance abusers by diuretic renogram.

METHODS

Twenty nine volatile substance abusers and 30 young healthy voluntary young men were included in our study. Technetium-99m mertiatide diuretic renogram was used to evaluate renal functions and collective system urodynamics to investigate the progress of renal functional damage. Images were evaluated visually and quantitatively. Split renal function of each kidney, time to peak activity (Tmax), and half-time for radiopharmaceutical clearance from pelvicalyceal system (T1/2), ratio of cortical and whole-kidney counts at 20-3 min, and maximum counts (T20/3 and T20/max) were compared in the two groups.

RESULTS

In the study group, time to reach peak activity was statistically prolonged compared with the healthy volunteers. In the volatile substance abuser group, the average Tmax values, average T1/2 values, cortical and whole-kidney T20/3, and T20/max values were found to be prolonged compared with the control group in the diuretic renogram. There was no significant difference in the split renal function ratios between the two groups.

CONCLUSION

In this study, possible renal functional damage was evaluated in volatile substance abusers by diuretic renogram. In conclusion, diuretic renogram can be useful in the evaluation of renal functional damage before blood renal function tests are affected and it could be used in the follow-up of the disease in volatile substance abusers. The results of this pilot study from our country, of course, should be supported by further clinical studies.

International Federation of Gynecology and Obstetrics opinion on reproductive health impacts of exposure to toxic environmental chemicals

Exposure to toxic environmental chemicals during pregnancy and breastfeeding is ubiquitous and is a threat to healthy human reproduction. There are tens of thousands of chemicals in global commerce, and even small exposures to toxic chemicals during pregnancy can trigger adverse health consequences. Exposure to toxic environmental chemicals and related health outcomes are inequitably distributed within and between countries; universally, the consequences of exposure are disproportionately borne by people with low incomes. Discrimination, other social factors, economic factors, and occupation impact risk of exposure and harm. Documented links between prenatal exposure to environmental chemicals and adverse health outcomes span the life course and include impacts on fertility and pregnancy, neurodevelopment, and cancer. The global health and economic burden related to toxic environmental chemicals is in excess of millions of deaths and billions of dollars every year. On the basis of accumulating robust evidence of exposures and adverse health impacts related to toxic environmental chemicals, the International Federation of Gynecology and Obstetrics (FIGO) joins other leading reproductive health professional societies in calling for timely action to prevent harm. FIGO recommends that reproductive and other health professionals advocate for policies to prevent exposure to toxic environmental chemicals, work to ensure a healthy food system for all, make environmental health part of health care, and champion environmental justice.

Changes in developmental body weight as a function of toluene exposure: A meta-analysis of animal studies

Inhalant abuse is a globally prevalent health issue with particular concerns about substance-abusing pregnant women. In both animal models and clinical case reports of toluene exposure, the primary physiological outcome measure of prenatal inhalant exposure is low birth weight (BW). However, the effect of prenatal toluene exposure on animal BW varies widely in the literature. To clarify this effect and investigate possible design moderators of pup BW, a systematic review and meta-analytic techniques were applied to the existing peer-reviewed animal literature of prenatal and postnatal exposure models to the inhaled solvent toluene. Of 288 studies screened, 24 studies satisfied the inclusion criteria. Evaluation of these studies indicated that toluene exposure was negatively associated with pup BW (d = -0.39), with external inhaled concentration, route of administration, day of weighing, and toluene exposure magnitude moderating this association. Investigators doing animal studies should be cognizant of these factors before investigating the reproductive and developmental outcomes associated with prenatal and postnatal toluene exposure.

Neonatal abstinence syndrome

Neonatal abstinence syndrome (NAS) is a result of the sudden discontinuation of fetal exposure to substances that were used or abused by the mother during pregnancy. Withdrawal from licit or illicit substances is becoming more common among neonates in both developed and developing countries. NAS continues to be an important clinical entity throughout much of the world. NAS leads to a constellation of signs and symptoms involving multiple systems. The pathophysiology of NAS is not completely understood. Urine or meconium confirmation may assist the diagnosis and management of NAS. The Finnegan scoring system is commonly used to assess the severity of NAS; scoring can be helpful for initiating, monitoring, and terminating treatment in neonates. Nonpharmacological care is the initial treatment option, and pharmacological treatment is required if an improvement is not observed after nonpharmacological measures or if the infant develops severe withdrawal. Morphine is the most commonly used drug in the treatment of NAS secondary to opioids. An algorithmic approach to the management of infants with NAS is suggested. Breastfeeding is not contraindicated in NAS, unless the mother is taking street drugs, is involved in polydrug abuse, or is infected with HIV. Future studies are required to assess the long-term effects of NAS on children after prenatal exposure.

Teratogenic risks from exposure to illicit drugs

Substance use is prevalent in the United States, especially in the reproductive age population. Even though a reduction in substance use may occur during pregnancy, some women may not alter their drug use patterns until at least pregnancy is confirmed. For these reasons, a large number of fetuses are exposed to illicit substances, including during critical stages of organogenesis. Associating illicit drug use with eventual pregnancy outcome is difficult. This article presents issues pertaining to limitations with published investigations about fetal risks and describes the most current information in humans about fetal effects from specific illicit substances.

Effects of the abused inhalant toluene on the mesolimbic dopamine system

Toluene is a representative member of a class of inhaled solvents that are voluntarily used by adolescents and adults for their euphorigenic effects. Research into the mechanisms of action of inhaled solvents has lagged behind that of other drugs of abuse despite mounting evidence that these compounds exert profound neurobehavioral and neurotoxicological effects. Results from studies carried out by the authors and others suggest that the neural effects of inhalants arise from their interaction with a discrete set of ion channels that regulate brain activity. Of particular interest is how these interactions allow toluene and other solvents to engage portions of an addiction neurocircuitry that includes midbrain and cortical structures. In this review, we focus on the current state of knowledge regarding toluene's action on midbrain dopamine neurons, a key brain region involved in the initial assessment of natural and drug-induced rewards. Findings from recent studies in the authors' laboratory show that brief exposures of adolescent rats to toluene vapor induce profound changes in markers of glutamatergic plasticity in VTA DA neurons. These changes are restricted to VTA DA neurons that project to limbic structures and are prevented by transient activation of the medial prefrontal cortex prior to toluene exposure. Together, these data provide the first evidence linking the voluntary inhalation of solvents to changes in reward -sensitive dopamine neurons.

Binge toluene exposure in pregnancy and pre-weaning developmental consequences in rats

Binge Toluene Exposure in Pregnancy and Pre-weaning Developmental Consequences in Rats. Bowen, S.E. and Hannigan, J.H. The persistent rate of abuse of inhaled organic solvents, especially among women of child-bearing age, raises the risk for teratogenic effects of maternal toluene abuse. In this study, timed-pregnant Sprague Dawley rats were exposed from Gestation Day (GD) 8 to GD20 to 12,000 or 8000 parts per million (ppm) toluene, or 0ppm (controls) for 30min twice daily, 60min total daily exposure. Pups were assessed from postnatal day (PN) 4 to PN21 using a developmental battery measuring growth (i.e., body weight), maturational milestones (e.g., eye opening & incisor eruption), and biobehavioral development (e.g., negative geotaxis & surface righting). Pups exposed in utero to 12,000ppm or 8000ppm toluene weighed significantly less than the non-exposed control pups beginning at PN4 and PN12 (respectively) until PN21. Toluene resulted in significant increases in an index of poor perinatal outcome, specifically a composite of malformations, defined "runting" and neonatal death. No significant delays were observed in reaching maturational milestones. The results reveal that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth retardation and malformations in rats. A comparison of the present, conservative results with findings in previous studies implies that binge patterns of toluene exposure in pregnant rats modeling human solvent abuse can result in developmental and morphological deficits in offspring. These results do not exclude the possibility that maternal toxicity as well as teratogenic effects of toluene may contribute to outcomes. The results suggest that abuse of inhaled organic solvents like toluene may result in similar early developmental outcomes in humans.

Toxic environmental chemicals: the role of reproductive health professionals in preventing harmful exposures

Every pregnant woman in the United States is exposed to many and varied environmental chemicals. Rapidly accumulating scientific evidence documents that widespread exposure to environmental chemicals at levels that are encountered in daily life can impact reproductive and developmental health adversely. Preconception and prenatal exposure to environmental chemicals are of particular importance because they may have a profound and lasting impact on health across the life course. Thus, prevention of developmental exposures to environmental chemicals would benefit greatly from the active participation of reproductive health professionals in clinical and policy arenas.

The Impact of a Science Education Game on Students' Learning and Perception of Inhalants as Body Pollutants

This study investigated the knowledge gains and attitude shifts attributable to a unique online science education game, Uncommon Scents. The game was developed to teach middle school students about the biological consequences of exposure to toxic chemicals in an environmental science context, as well as the risks associated with abusing these chemicals as inhalants. Middle school students (n = 444) grades six through eight participated in the study consisting of a pre-test, three game-play sessions, and a delayed post-test. After playing the game, students demonstrated significant gains in science content knowledge, with game usability ratings emerging as the strongest predictor of post-test content knowledge scores. The intervention also resulted in a shift to more negative attitudes toward inhalants, with the most negative shift occurring among eighth grade students and post-test knowledge gains as the strongest predictor of attitude change across all grade levels. These findings suggest that the environmental science approach used in Uncommon Scents is an efficacious strategy for delivering both basic science content and influencing perceived harm relating to the inhalation of toxic chemicals from common household products.

Anaesthetic considerations for non-obstetric surgery during pregnancy

Surgery during pregnancy is complicated by the need to balance the requirements of two patients. Under usual circumstances, surgery is only conducted during pregnancy when it is absolutely necessary for the wellbeing of the mother, fetus, or both. Even so, the outcome is generally favourable for both the mother and the fetus. All general anaesthetic drugs cross the placenta and there is no optimal general anaesthetic technique. Neither is there convincing evidence that any particular anaesthetic drug is toxic in humans. There is weak evidence that nitrous oxide should be avoided in early pregnancy due to a potential association with pregnancy loss with high exposure. There is evidence in animal models that many general anaesthetic techniques cause inappropriate neuronal apoptosis and behavioural deficits in later life. It is not known whether these considerations affect the human fetus but studies are underway. Given the general considerations of avoiding fetal exposure to unnecessary medication and potential protection of the maternal airway, regional anaesthesia is usually preferred in pregnancy when it is practical for the medical and surgical condition. When surgery is indicated during pregnancy maintenance of maternal oxygenation, perfusion and homeostasis with the least extensive anaesthetic that is practical will assure the best outcome for the fetus.

Two serious and challenging medical complications associated with volatile substance misuse: sudden sniffing death and fetal solvent syndrome

Volatile substance misuse is a prevalent and often overlooked behavior among adolescents, including reported use among young pregnant women. Several medical repercussions can arise from the improper use of volatile substances, yet they are often underappreciated among scientists and health professionals. This brief review reports on the recent advances made in the preclinical and clinical data about two serious medical complications surrounding volatile substance misuse: sudden sniffing death and fetal solvent syndrome. Suggestions for treatment interventions are discussed. The paper's limitations are noted.

Glue Sniffing: A Review

Inhalant abuse is a prevalent and often overlooked form of substance abuse in adolescents and young adults. It causes a euphoric feeling, may become addictive and can be a serious health concern associated with significant morbidity and mortality. Acute effects of inhalants include sudden sniffing death syndrome, asphyxia, and traumatic injuries. Chronic inhalant abuse can damage the brain, heart, lung, kidney, liver, and bone marrow in addition to being an important cause of psychosocial and economic problems. This article is proposed to emphasize on the harmful effects of glue-sniffing, its prevention and management.

The mysterious practice of petrol sniffing in isolated indigenous groups

The practice of petrol sniffing is a unique and poorly understood phenomenon that is associated with substantial morbidity, mortality and social devastation in affected remote Indigenous communities. For these groups and for the wider community, much mystery has surrounded the practice and its effects. Here we introduce the epidemiology of petrol sniffing among Indigenous groups internationally, review its impact on the brain, behaviour and social functions and summarise related interventions.

Neurotoxicity of toluene

Chemical susceptibility is triggered by a large range of chemicals present both indoors and outdoors including pesticides, cleaning products, perfumes, scented products and cigarette smoke. Health risk after chemical exposure depends on age, sex, genetic factors, socioeconomic status, nutritional status, and environmental factors. Toluene is one of volatile organic chemicals that causes different sensitivity in individuals. Although neurotoxic and immunotoxic effects of toluene have been studied extensively, the underlying mechanism remains obscure. This review highlights the possible neuroimmune factors influencing toluene sensitivity and neurotoxicity in a mouse model.

Reproductive toxicology and teratology of abused toluene

Toluene is an organic solvent that is widely used by industry and is ubiquitous in our environment. As a result, exposure to solvents like toluene in work-related settings (i.e., relatively constant, low-level exposures) or through inhalant abuse (i.e., relatively intermittent, high-level exposures) is increasing for many women of reproductive age. Evidence suggests that the risk for pregnancy problems, as well as developmental delays and neurobehavioral difficulties, is higher for the children of women who have been exposed to high concentrations of organic solvents during pregnancy than for those who have not. These risks appear to be higher in cases of abuse exposure to solvents such as toluene, particularly in comparison to the risk for teratogenic outcomes with occupational solvent exposure. Despite this, the reproductive toxicology and teratology following abuse of toluene and other inhalants remains under-investigated. This brief review describes the current state of our understanding of the reproductive and teratogenic risk of gestational toluene abuse. The data to date suggest that the high levels of toluene exposure typical with inhalant abuse are more detrimental to fetal development than typical occupational exposure, and preclinical paradigms can be beneficial for investigating the processes and risks of prenatal solvent exposure. While substantial research has been done on the reproductive effects of occupational exposures to organic solvents, more research is needed on the outcomes and mechanisms of exposures typical of inhalant abuse.

A survey of inhalant use disorders among delinquent youth: prevalence, clinical features, and latent structure of DSM-IV diagnostic criteria

BACKGROUND

Inhalant use is among the most pernicious and poorly understood forms of adolescent substance use. Many youth in the juvenile justice system have used inhalants, but little is known about inhalant use disorders (IUDs) in antisocial youth populations. The purpose of this study was to examine the prevalence, clinical features, and latent structure of DSM-IV IUDs in a state population of antisocial youth.

METHODS

Cross-sectional survey conducted in 2003. Of 740 youth residing in Missouri State Division of Youth Services' (MDYS) residential treatment facilities at the time the study was conducted, 723 (97.7%) completed interviews. Eighty-seven percent were male, with a mean age of 15.5 (SD = 1.2). Nearly 4 in 10 youth (38.5%; n = 279) reported lifetime inhalant use. Youth ranged from very mildly to severely antisocial.

RESULTS

Of 279 inhalant users, 52 (18.6%) met DSM-IV inhalant abuse criteria and 79 (28.3%) met inhalant dependence criteria. Five of 10 IUD criteria were met by > 10% of the total sample. Latent class analyses demonstrated a substantial concordance between DSM-IV-defined IUDs and an empirically-derived classification based on responses to DSM-IV IUD diagnostic criteria.

CONCLUSION

IUDs and constituent criteria were prevalent among youth in the juvenile justice system. Two groups of problem inhalant users were identified, symptomatic users-DSM-IV inhalant abuse and highly symptomatic users-DSM-IV inhalant dependence, which differed primarily in severity of inhalant-related problems. Inhalant screening, prevention and treatment efforts in juvenile justice settings are rarely delivered, but critically needed.

Alterations in rat fetal morphology following abuse patterns of toluene exposure

Toluene is a commonly abused organic solvent. Inhalant abusers are increasingly women in their prime childbearing years. Children born to mothers who abused solvents during pregnancy may exhibit characteristics of a "fetal solvent syndrome" which may include dysmorphic features. This study examined the teratological effects of an abuse pattern of binge toluene exposure during gestation on skeletal and soft tissue abnormalities, body weight, and body size in fetal rats. Pregnant Sprague-Dawley rats were exposed for 30 min, twice daily, from gestational day (GD) 8 through GD20 to either air (0 ppm), 8000 ppm, 12,000 ppm, or 16,000 ppm toluene. Two-thirds of each litter was prepared for skeletal examination using Alizarin Red S staining while the remaining third of each litter was fixed in Bouin's solution for Wilson's soft tissue evaluation. Exposure to toluene at all levels significantly reduced growth, including decreases in placental weight, fetal weight, and crown-rump length. In addition, numerous gross morphological anomalies were observed such as short or missing digits and missing limbs. Skeletal examination revealed that ossification of the extremities was significantly reduced as a result of toluene exposure at all levels. Specific skeletal defects included misshapen scapula, missing and supernumerary vertebrae and ribs, and fused digits. Soft tissue anomalies were also observed at all toluene levels and there was a dose-dependent increase in the number of anomalies which included cryptorchidism, displaced abdominal organs, gastromegaly, distended/hypoplastic bladder, and delayed cardiac development, among others. These results indicate that animals exposed prenatally to levels and patterns of toluene typical of inhalant abuse are at increased risk for skeletal and soft tissue abnormalities.

Inhalant abuse among adolescents: neurobiological considerations

Experimentation with volatile substances (inhalants) is common during early adolescence, yet limited work has been conducted examining the neurobiological impact of regular binge use during this key stage of development. Human studies consistently demonstrate that chronic use is associated with significant toxic effects, including neurological and neuropsychological impairment, as well as diffuse and subtle changes in white matter. However, most preclinical research has tended to focus on acute exposure, with limited work examining the neuropharmacological or toxicological mechanisms underpinning these changes or their potential reversibility with abstinence. Nevertheless, there is growing evidence that commonly abused inhalants share common cellular mechanisms, and have similar actions to other drugs of abuse. Indeed, the majority of acute behavioural effects appear to be underpinned by changes in receptor and/or ion channel activity (for example, GABA(A), glycine and 5HT(3) receptor activation, NMDA receptor inhibition), although nonspecific interactions can also arise at high concentrations. Recent studies examining the effects of toluene exposure during the early postnatal period are suggestive of long-term alterations in the function of NMDA and GABA(A) receptors, although limited work has been conducted investigating exposure during adolescence. Given the critical role of neurotransmitter systems in cognitive, emotional and brain development, future studies will need to take account of the substantial neuromaturational changes that are known to occur in the brain during childhood and adolescence, and to specifically investigate the neuropharmacological and toxicological profile of inhalant exposure during this period of development.

Inhalant use among incarcerated adolescents in the United States: prevalence, characteristics, and correlates of use

OBJECTIVE

To characterize patterns and correlates of inhalant use among incarcerated youth.

METHOD

Residents (N=723) of 27 Missouri Division of Youth Services facilities completed interviews assessing substance use, psychiatric symptoms, antisocial traits, trauma, suicidality, and criminality.

RESULTS

Participants averaged 15.5 (S.D.=1.2) years of age, were ethnically diverse, and predominantly male. More than one-third (36.9%) reported lifetime inhalant use; 47.9% of users had tried four or more inhalant products. Comparatively high rates of use were observed for Hispanic and small town/rural youth. Commonly abused agents included gasoline (22%), permanent markers (15%), computer "air duster," (15%) and spray paint (12%). Inhalant users evidenced significantly higher levels of criminal behavior, antisocial attitudes, current psychiatric symptoms, earlier onset of offending and substance use, and more extensive histories of head injury, kidney disease, hormonal problems, mental illness, suicidality, trauma, and substance-related problems than nonusers. In multiple logistic regression models, race/ethnicity, geographic area of residence, fearlessness, suicidality, and polydrug use distinguished inhalant users and nonusers. Measures of cognitive impairment, impulsivity, fearlessness, blame externalization, polydrug use, and substance-related problems were positively associated with lifetime frequency of inhalant use.

CONCLUSIONS

Inhalant use was widespread in this sample and associated with serious physical and mental health impairments.

Maternal and fetal blood and organ toluene levels in rats following acute and repeated binge inhalation exposure

Inhalation of organic solvents is a persistent form of drug abuse with particular concern being the abuse of inhalants by women of child-bearing age. While studies have begun assessing postnatal outcomes of offspring exposed prenatally to inhalants, relatively little is known about the distribution of toluene in blood and body tissues of pregnant, inhalant-abusing women, or in the fetuses. The present study assessed the tissue toluene levels attained following brief toluene exposures using a pre-clinical rat model of maternal inhalant abuse. Timed-pregnant Sprague-Dawley rats were exposed to toluene at 8000 or 12,000 parts per million (ppm) for 15, 30 or 45 min/exposure. Exposures occurred twice each day from gestational day 8 (GD8) through GD20. Immediately following the second exposure on GD8, GD14 and GD20 blood was taken from the saphenous vein of the dams. Following saphenous vein blood collection on GD20, dams were sacrificed and trunk blood was collected along with maternal tissue specimens from cerebellum, heart, lung, kidney and liver. The placenta, amniotic fluid and fetal brain were also collected. Results demonstrated that maternal saphenous blood toluene levels increased as the inhaled concentration of toluene and duration of exposure increased. The maternal cerebellum, heart, kidney and liver appeared to be saturated after 30 min on GD20 such that toluene levels in those organs were equivalent across all ambient concentrations of inhaled toluene. Toluene levels also increased in fetal brain as the inhaled concentration of toluene increased and in placenta and amniotic fluid as the duration of exposure increased. Toluene levels in all tissues at GD20, except maternal lung and amniotic fluid, were higher than in maternal saphenous blood suggesting that toluene concentrated in those organs. Measurement of toluene levels in blood and other tissues following repeated toluene exposure demonstrated that toluene readily reaches a variety of potential sites of action throughout the maternal-placental-fetal unit.

Gestational toluene exposure effects on spontaneous and amphetamine-induced locomotor behavior in rats

Gestational Toluene Exposure Effects on Spontaneous and Amphetamine-Induced Locomotor Behavior in Rats. Bowen, S.E., Mohammadi, M.H., Batis, J.C., and Hannigan, J.H. Neurotoxicology and Teratology, XX, 2006. The abuse of volatile organic solvents (inhalants) continues to be a major health concern throughout the world. Toluene, which is found in many products such as glues and household cleaners, is among the most commonly abused organic solvents. The neurobehavioral teratogenic sequelae of solvent abuse (i.e., repeated, brief inhalation exposures to very high concentrations of solvents) have not been examined thoroughly. In a preclinical model of inhalant abuse, timed-pregnant Sprague-Dawley rats were exposed to 0, 8000, or 12,000 parts per million (ppm) for 15 min twice daily from gestation day 8 (GD8) through GD20. In the first experiment, separate groups of offspring were observed individually in an open-field on postnatal day 22 (PN22), PN42 or PN63. In the second experiment, other offspring given identical prenatal toluene exposures were observed in an "open-field" following an acute i.p. injection of amphetamine (0, 0.56, 1.78 mg/kg) on PN28. Automated measurements of distance traveled and ambulatory time were recorded. Prenatal toluene exposure resulted in small alterations in spontaneous activity compared to non-exposed rats. Prenatal exposure to 12,000 ppm toluene resulted in significant hyposensitivity to the locomotor stimulatory effects of the amphetamine challenge in male but not female rats on PN28. The results demonstrate that prenatal exposure to abuse patterns of high concentrations of toluene through inhalation can alter spontaneous and amphetamine-induced locomotor behavior in rats. The expression of these effects also appears to depend upon the postnatal age of testing. These results imply that abuse of organic solvents during pregnancy in humans may also produce long-lasting effects on biobehavioral development.

The last decade of solvent research in animal models of abuse: mechanistic and behavioral studies

The abuse of volatile organic solvents (inhalants) leads to diverse sequelae at levels ranging from the cell to the whole organism. This paper reviews findings from the last 10 years of animal models investigating the behavioral and mechanistic effects of solvent abuse. In research with animal models of inhalant abuse, NMDA, GABA(A), glycine, nicotine, and 5HT(3) receptors appear to be important targets of action for several abused solvents with emerging evidence suggesting that other receptor subtypes and nerve membrane ion channels may be involved as well. The behavioral effects vary in magnitude and duration among the solvents investigated. The behavioral effects of acute and chronic inhalant abuse include motor impairment, alterations in spontaneous motor activity, anticonvulsant effects, anxiolytic effects, sensory effects, and effects on learning, memory and operant behavior (e.g., response rates and discriminative stimulus effects). In addition, repeated exposure to these solvents may produce tolerance, dependence and/or sensitization to these effects.

Developmental toxicity of prenatal exposure to toluene

Organic solvents have become ubiquitous in our environment and are essential for industry. Many women of reproductive age are increasingly exposed to solvents such as toluene in occupational settings (ie, long-term, low-concentration exposures) or through inhalant abuse (eg, episodic, binge exposures to high concentrations). The risk for teratogenic outcome is much less with low to moderate occupational solvent exposure compared with the greater potential for adverse pregnancy outcomes, developmental delays, and neurobehavioral problems in children born to women exposed to high concentrations of abused organic solvents such as toluene, 1,1,1-trichloroethane, xylenes, and nitrous oxide. Yet the teratogenic effects of abuse patterns of exposure to toluene and other inhalants remain understudied. We briefly review how animal models can aid substantially in clarifying the developmental risk of exposure to solvents for adverse biobehavioral outcomes following abuse patterns of use and in the absence of associated health problems and co-drug abuse (eg, alcohol). Our studies also begin to establish the importance of dose (concentration) and critical perinatal periods of exposure to specific outcomes. The present results with our clinically relevant animal model of repeated, brief, high-concentration binge prenatal toluene exposure demonstrate the dose-dependent effect of toluene on prenatal development, early postnatal maturation, spontaneous exploration, and amphetamine-induced locomotor activity. The results imply that abuse patterns of toluene exposure may be more deleterious than typical occupational exposure on fetal development and suggest that animal models are effective in studying the mechanisms and risk factors of organic solvent teratogenicity.

Anesthetic management of the illicit-substance-using patient

PURPOSE OF REVIEW

During the last few years, drug abuse has risen to the point that almost 20 million Americans are current abusers of illicit substances. These patients present to us as anesthesiologists in a variety of circumstances: in obstetrics for labor and emergencies, in trauma for emergency surgeries or life-saving (resuscitative) situations and in everyday elective surgeries. Therefore it is important for anesthesiologists to know about the most common illicit drugs being used, to know their side effects and clinical presentation if abused or intoxicated, and to know what anesthetic options would be beneficial or detrimental.

RECENT FINDINGS

In this article we will review some of the most commonly used illicit drugs, their effects on the organ systems and some tips to take into consideration when providing anesthesia for these patients. We will discuss marijuana, cocaine, opioids, hallucinogens, solvents and the newer so-called rave or club drugs. Newer treatment options for opioid detoxification will also be discussed.

SUMMARY

Illicit substance abuse is a major health concern in the United States. Drug use, either acute or chronic, has potentially grave consequences which include changes affecting the pulmonary, cardiovascular, nervous, renal and hepatic systems. Anesthesiologists come into contact with these patients in emergency and everyday situations. Due to the diverse clinical presentations that may arise from single substance or polysubstance abuse, anesthetic management should be tailored to each individual and universal precautions should always be followed when providing care.

Abuse pattern of gestational toluene exposure and early postnatal development in rats

Inhalant abuse in the United States trails only alcohol, marijuana and nicotine abuse. Toluene, found in glues and cleaners, is among the most commonly abused inhalants. While teratogenicity due to occupational exposure to organic solvents (i.e., relatively long-term exposure to lower concentrations) has been studied, the teratogenic potential of organic solvent abuse (i.e., brief inhalation exposures to very high concentrations) has not been thoroughly examined. In a preclinical model of abuse patterns of fetal solvent exposure, timed-pregnant rats were exposed to 8000 parts per million (ppm) or 12,000 ppm of toluene, or to air (0 ppm), for 15 min twice daily from gestation day 8 (GD8) through GD20. After parturition, pups were tested from postnatal day 4 (PN4) to PN21 in a developmental test battery including measures of growth (i.e., body weight), maturational milestones (i.e., pinnae unfolding, incisor eruption and eye opening) and biobehavioral development (e.g., negative geotaxis, surface righting and grip strength). Pups exposed in utero to 12,000 ppm toluene weighed significantly less than the control pups at all ages before PN16. There were significant toluene-induced increases in an index of poor perinatal outcome (i.e., a combination of malformations, "runting" and neonatal death) and deficits in negative geotaxis. There were no significant delays in reaching maturational milestones. The results demonstrate that brief, repeated, prenatal exposure to high concentrations of toluene can cause growth restriction, malformation and impairments of biobehavioral development in rats. A comparison of the present outcomes to previous studies of occupational exposure patterns suggests that for a given daily "dose" of toluene, a binge pattern of exposure may pose a greater risk for fetal development. Since the pattern of exposure in this experiment models binge exposure in human solvent abuse, the results imply that abuse of inhaled organic solvents, such as toluene, can cause similar teratogenic outcomes in humans.

Anesthetic implications of drug abuse in pregnancy

Substance abuse has crossed social, economic, and geographic borders and--throughout the world--remains one of the major problems facing society today. The prevalence of substance abuse in young adults (including women) has increased markedly over the past 20 years. Nearly 90% of drug-abusing women are of childbearing age. Consequently, it is not unusual to encounter pregnant women who abuse illicit drugs, as numerous case reports of drug abuse in pregnancy confirm. The diverse clinical manifestations of drug abuse combined with physiologic changes of pregnancy, and pathophysiology of coexisting pregnancy-related disease may lead to life-threatening complications and significantly impact the practice of obstetrical anesthesia. Regardless of the drug(s) ingested and clinical manifestations, it is always difficult to predict the exact anesthetic implications in chemically dependent patients.

Labor analgesia for the drug abusing parturient: is there cause for concern?

Drug abuse has crossed geographic, economic and social borders, and it remains one of the major problems facing our society today. The prevalence of recreational drug abuse among young adults (including women) has increased markedly over the past two decades. Nearly 90% of drug abusing women are of childbearing age. Consequently, it is not surprising to find pregnant women with a history of drug addiction. Obstetricians and obstetric anesthesiologists become involved in the care of drug abusing patients either in emergency situations, such as placental abruption, uterine rupture or fetal distress, or in more controlled situations, such as request for labor analgesia. The diverse clinical manifestations of maternal substance abuse may result in life-threatening complications and significantly impact the peripartum care of these patients.

TARGET AUDIENCE

Obstetricians & Gynecologists, Family Physicians.

LEARNING OBJECTIVES

After completion of this article, the reader will be able to list the most commonly abused substances during pregnancy, to describe the various effects of particular substances on pregnancy including the mechanism of desired effect for various substances, and to outline the obstetric anesthesia recommendations for the various substances abused during pregnancy.

Inhaled drugs of abuse enhance serotonin-3 receptor function

Despite the prevalence of their use, little is currently known of the molecular mechanisms of action of inhaled drugs of abuse. Recent studies have shown effects on NMDA, GABA(A) and glycine receptors in vitro, suggesting that inhalants may exert at least some of their pharmacological effects on ligand-gated ion channels. Enhancement of serotonin-3 receptor function has been shown to play a role in the reinforcing properties of drugs of abuse. We tested the hypothesis that the commonly abused inhaled agents 1,1,1-trichloroethane, trichloroethylene, and toluene enhance serotonin-3 receptor function. All three inhalants significantly and reversibly potentiated, in a dose-dependent manner, serotonin-activated currents mediated by mouse serotonin-3A receptors expressed in Xenopus oocytes. Our findings add the serotonin-3 receptor to the growing list of molecular targets commonly affected by both inhalants and classic CNS depressants such as ethanol and the volatile anesthetics.

Inhalant abuse in the pediatric population: a persistent challenge

Inhalants remain one of the most commonly abused substances by adolescents in the United States today. Recent epidemiologic studies have demonstrated a decrease in the prevalence of inhalant abuse, but overall rates remain high. Inhalants have the potential to result in serious organ system dysfunction or even sudden death. This article reviews the most recent epidemiologic data on inhalant abuse, summarizes the types of substances used and their mechanism of actions, and discusses clinical toxicity and medical management.

Developmental toxicity: web resources for evaluating risk in humans

This review presents a brief overview of Internet resources that provides information on developmental toxicity. The advantages and limitations of these resources for evaluating human risk and where each one is useful for informing various stages of the risk assessment process (i.e. hazard characterization, dose-response assessment, exposure assessment and risk characterization) are reviewed. How these Internet resources can be utilized to obtain information on and evaluate the developmental risk associated with exposures during pregnancy will be illustrated using toluene. Translating information derived from laboratory and human population studies into clinical management prescriptions for individual patients is difficult. With the increasing availability of Internet resources that provide information relevant for developmental risk assessments, health care professionals will be better equipped to make more accurate estimations of potential risk for their patients.

Developmental neurotoxicity: do similar phenotypes indicate a common mode of action? A comparison of fetal alcohol syndrome, toluene embryopathy and maternal phenylketonuria

Developmental neurotoxicity can be ascribed to in utero exposure to exogenous substances or to exposure of the fetus to endogenous compounds that accumulate because of genetic mutations. One of the best recognized human neuroteratogens is ethanol. The Fetal Alcohol Syndrome (FAS) is characterized by growth deficiency, particular facial features, and central nervous system (CNS) dysfunctions (mental retardation, microencephaly and brain malformations). Abuse of toluene by pregnant women can lead to an embryopathy (fetal solvent syndrome, (FSS)) whose characteristics are similar to FAS. Phenylketonuria (PKU) is a genetic defect in phenylalanine (Phe) metabolism. Offspring of phenylketonuric mothers not under strict dietary control are born with maternal PKU (mPKU), a syndrome with similar characteristics as FAS and FSS. While ethanol has been shown to cause neuronal death, no such evidence is available for toluene or Phe and/or its metabolites. On the other hand, alterations in astrocyte proliferation and maturation have been found, mostly in in vitro studies, which may represent a potential common mode of action for at least some of the CNS effects found in FAS, mPKU, and FSS. Further in vivo and in vitro studies should validate this hypothesis and elucidate possible molecular targets.

Changes in markers of oxidative stress and membrane properties in synaptosomes from rats exposed prenatally to toluene

The present study was undertaken in order to investigate if toluene induced oxidative stress in brains from rats exposed prenatally to 1800 ppm toluene 6 hr/day at days 7-20 during the pregnancy. 35-42 days after birth the rats were killed and synaptosomal fractions were prepared for the experiments. Synaptosomes from rats exposed prenatally to toluene exhibited an increased level of oxidative stress when incubated with toluene in vitro compared to synaptosomes from unexposed offspring. Also the cell membrane was affected, as the calcium leakage was more increased from exposed synaptosomes than from unexposed. The membrane fluidity increased significantly when synaptosomes were incubated with toluene for 10 min. in vitro but the change in fluidity was identical in both groups of offspring. The results indicate that prenatal exposure to toluene induces long-lasting changes in oxidative status and membrane function.

Solvent abuse in pregnancy: a perinatal perspective

OBJECTIVE

To review the scope and sequelae of solvent abuse in women presenting to a Manitoba teaching hospital.

METHODS

Fifty-six patient charts with a diagnosis of solvent abuse in pregnancy were identified through computer search in the medical records of Winnipeg Health Sciences Centre, General Hospital. These charts were reviewed and data obtained from birthing records and associated pediatric charts.

RESULTS

Renal tubular acidosis was diagnosed in three patients (5.3%). Two patients (3.6%) had adverse neurological sequelae. One patient was diagnosed with brain damage, including expressive aphasia. Twelve patients (21.4%) delivered preterm infants. Nine infants (16.1%) had major anomalies. Seven infants (12.5%) had fetal alcohol syndrome (FAS)-like facial features. Six neonates (10.7%) had hearing loss.

CONCLUSION

Substance abuse in pregnancy is associated with severe maternal and neonatal sequelae. Physicians must be aware of this increasing problem in the obstetrical population and assistance should be offered to each woman, ideally before a woman becomes pregnant, but at least at the first contact a pregnant woman makes with the health care community.

Petrol sniffing in a pregnant Aboriginal population: a review of maternal and neonatal outcomes

The study's aim was to determine if petrol sniffing during pregnancy is associated with adverse maternal and neonatal outcomes at the Alice Springs Hospital. The study design was a retrospective case note review. The subjects were Aboriginal women who delivered at the Alice Springs Hospital between July 1991 and September 1999 where petrol sniffing was identified on the discharge coding; 14 women with 21 pregnancies were identified. One hundred and eleven nulliparous Aboriginal women who delivered at hospital between July 1998 and June 1999, with singleton gestation in cephalic presentation, were identified from the birth register and used as the control group. We found that women identified as petrol sniffers during pregnancy presented later for antenatal care, had fewer antenatal visits, lower booking haemoglobin and weighed less at booking when compared with non-petrol-sniffing women. Women who sniffed petrol during pregnancy were more likely to have one or more sexually transmitted diseases identified during the pregnancy; to use other substances during pregnancy; to be colonised with group B Streptococcus; to have meconium stained liquor prior to delivery; and to have a still-birth. Infants born to petrol-sniffing mothers were more likely to have birthweight less than 2,500 g; to have Apgar scores of less than 7 at 5 minutes; to require admission to the neonatal unit; and to be placed in foster care or for adoption. We concluded that the pregnancy complicated by petrol sniffing should be recognised as one at increased risk of adverse outcome, necessitating increased antenatal surveillance. However, as with other substances abused, it is extremely difficult to determine the role played by the substance per se, and that of the lifestyle associated with the abuse behaviour.

Review of the epidemiological evidence relating toluene to reproductive outcomes

This review examines the epidemiological evidence for adverse reproductive outcomes from those occupational studies that present toluene-specific findings. Clinical investigations of the reproductive effects of toluene abuse are also examined. Six occupational studies reported associations between toluene and spontaneous abortion, two between toluene and congenital malformation, and three between toluene and reduced fertility. The spontaneous abortion studies provided the most suggestive evidence for an association with toluene. However, the potential for bias in some of these studies, the relatively homogeneous nature of the populations examined (e.g., four of the six studies evaluated similar groups of Finnish workers), and the multiple chemicals to which most workers were simultaneously exposed suggest cautious interpretation of these findings. Also, spontaneous abortion has generally not been observed as a major problem among highly exposed women who abuse toluene during pregnancy. The results of the occupational studies should be considered "hypothesis generating". Truly prospective studies with individually monitored data on toluene exposure and early fetal loss are needed to more definitively investigate this issue.

Inhalant abuse by adolescents

The deliberate misuse of volatile substances poses a poorly recognized risk for considerable morbidity and mortality in adolescent populations worldwide. The abuse of inhalants continues to be a significant problem among our country's youth. While many household and industrial chemicals can be inhaled, glues, paints, and aerosol propellants are among the most commonly abused. Adolescents are often unaware of the health threats posed by inhalation of solvents. Inhalation can result in serious organ system dysfunction or even sudden death. This review discusses the prevalence of inhalant abuse in the United States, summarizes the various types of substances used, highlights the major physiologic effects of inhalants, and briefly discusses associated risk behaviors, prevention and medical management.