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PubMedDate not supplied

Nasal function in self-reported chemically intolerant individuals.

Nasal function has not yet been investigated under controlled exposures in individuals with self-reported Multiple Chemical Sensitivity (sMCS). Therefore, anterior rhinomanometry and acoustic rhinometry were applied in 12 individuals with sMCS, and 12 age-matched controls. The sMCS individuals and controls were selected on the basis of a standardized questionnaire. Controlled 4-hr exposures to ethylbenzene and 2-butanone were performed during 4 sessions. Exposures were close to the current German threshold limit values, and they approximated odor thresholds. Subjects with sMCS had a significant decrease in the flow value in anterior rhinomanometry, independent of substance and doses, compared with controls. This result suggests somatic reactions to the exposure. The result must be confirmed in additional studies, and pathophysiological examinations must be performed. For these investigations, anterior rhinomanometry was usable, but acoustic rhinometry can be recommended only after sufficient standardization has occurred. Furthermore, biochemical parameters of nasal mucosa must be considered.

Administration, Intranasal↗
PubMedDate not supplied

Neuropsychology and psychology of MCS.

Neurological symptoms are frequently reported by patients with multiple chemical sensitivities (MCS). Methods to compare the psychiatric, personality, and neuropsychological function of patients with MCS, chronic fatigue syndrome (CFS), and normal controls are described. Increased rates of Axis I psychiatric diagnoses are observed in the literature for MCS and CFS subjects relative to controls. Findings on the MMPI-2 and the Toronto Alexithymia Scale reveal profiles consistent with the tendency to report somatic rather than emotional symptoms in response to stress. However, many of the reported somatic symptoms also coincide with those found in neurologic disorders. The overall neuropsychological profile for MCS subjects does not reflect cognitive impairment. Relative to normal controls, the only difference in neuropsychological performance observed is reduced recognition of nontarget designs on a visual memory task. More fruitful areas for future psychological research will include measurement of the interaction between behavioral response styles and attentional processes in cognition, as well as observations under controlled challenge conditions.

Central Nervous System↗
PubMed2005

[Chronic fatigue syndrome and multiple chemical hypersensitivity after insecticide exposure].

BACKGROUND AND OBJECTIVE: Chronic Fatigue Syndrome (CFS) and Multiple Chemical Sensitivity (MCS) are well-defined illnesses that may appear after some toxic exposures. PATIENTS AND METHOD: We report a consecutive series of 26 patients who developed CFS after exposure to insecticide products. It was associated with MCS in a third of cases. RESULTS: Toxic exposure was of labour origin after returning to usual work place after a process of fumigation. In 42% of cases there was no fulfilment of fumigation safety rules. The majority of patients were mean-aged women who developed an acute upper airway inflammatory syndrome, without muscarinic or nicotinic manifestations, followed by digestive syndrome, neurocognitive, fibromyalgic and chronic fatigue manifestations. The course of disease was shorter than 1 year in 5 cases (19%), longer than 1 year in 15(58%), and disabling in 6 cases (23%). CONCLUSIONS: Due to the possible prevention of this toxic exposure, it is very important to carefully follow measures of environment isolation and ventilation after insecticide use in order to avoid the development of these diseases.

Adolescent↗
PubMed2003

Are syndromes in environmental medicine variants of somatoform disorders?

To date, relatively little is known about the etiology, pathophysiology, diagnosis, therapy, prevention and prognosis of environment-related syndromes like multiple chemical sensitivity (MCS), idiopathic environmental intolerance (IEI), sick building syndrome (SBS), chronic fatigue syndrome (CFS), candida syndrome (CS) and burnout syndrome (BS). Part of the reason is that these syndromes have not been clearly defined and classified in scientific categories distinct from each other, and that they show clinical similarities to classified somatoform disorders. Furthermore, there are at least three possible explanations for the existence of these syndromes: (1) The syndromes may result from the interaction of environmental factors, individual susceptibility and psychological factors (i.e., how they are perceived and seen by the patient); (2) they may reflect socially and culturally accepted methods of expressing distress; and/or (3) they may be iatrogenic. Despite all the uncertainties in evaluation of environmental syndromes, physicians have the duty to take the affected person's problems seriously. A comprehensive systematic classification which better accounts for these complex clinical manifestations is long overdue. Until these syndromes are well defined, the terms used for them should definitely not be applied to connote a specific disease process.

Environment↗
PubMed2003

Idiopathic environmental intolerance: Part 1: A causation analysis applying Bradford Hill's criteria to the toxicogenic theory.

Idiopathic environmental intolerance (IEI) is a descriptor for a phenomenon that has many names including environmental illness, multiple chemical sensitivity and chemical intolerance. Toxicogenic and psychogenic theories have been proposed to explain IEI. This paper presents a causality analysis of the toxicogenic theory using Bradford Hill's nine criteria (strength, consistency, specificity, temporality, biological gradient, biological plausibility, coherence, experimental intervention and analogy) and an additional criteria (reversibility) and reviews critically the scientific literature on the topic. The results of this analysis indicate that the toxicogenic theory fails all of these criteria. There is no convincing evidence to support the fundamental postulate that IEI has a toxic aetiology; the hypothesised biological processes and mechanisms are implausible.

Animals↗
PubMed1999

Psychosocial factors in the occurrence of environmental intolerances.

The phenomenon referred to as environmental illness, especially multiple chemical sensitivity, is an extremely controversial and puzzling issue. Despite the seeming gestalt of the disease there is no objective measure for diagnosis and pathophysiology. Psychological and psychosocial factors have a significant role in the presentation and prospects of the disease. Medical neglect of the suffering of the patients as well as iatrogenic attribution towards a chemical intoxication might both increase the risk of chronification and social isolation of patients up to a point of no return. Several observations and results from studies with environmental patients and in related fields are presented and discussed with the aim to encourage continuous research and a critical approach towards a phenomenon where the political necessity to decide is more advanced than the ability to understand.

Diagnosis, Differential↗
PubMedDate not supplied

Comorbid illness in women with chronic fatigue syndrome: a test of the single syndrome hypothesis.

OBJECTIVE: Evidence of comorbidity among unexplained illness syndromes raises the possibility that all are variants of a single functional disorder, leading some to suggest that separate case definitions for chronic fatigue syndrome (CFS), fibromyalgia (FM), and multiple chemical sensitivity (MCS) may be unnecessary. Our objective was to determine whether discrete diagnostic labels provide useful information about physical functioning, symptom severity, and risk of psychiatric illness. METHODS: The sample consisted of 163 consecutive female referrals with CFS enrolled at a tertiary clinic. Each participant was retrospectively assigned to one of four groups: CFS only, CFS/FM, CFS/MCS, and CFS/FM/MCS. At enrollment, participants gave their history, underwent a physical examination and a standardized psychiatric interview (Diagnostic Interview Schedule), and answered self-report questionnaires. RESULTS: Additional unexplained syndromes were prevalent: 37% met criteria for FM, and 33% met criteria for MCS. With the exception of FM-related pain and disability, there were few differences between the CFS only and CFS with comorbid illness groups. Patients with additional illness were more likely to have major depression and a higher risk of psychiatric morbidity compared with patients in the CFS only group (p <.01). Rates of lifetime depression increased from 27.4% in the CFS only group to 52.3% in the CFS/FM group, 45.2% in the CFS/MCS group, and 69.2% in the CFS/FM/MCS group. CONCLUSIONS: The prevalence of comorbid illness in the present CFS sample and the failure to find widespread differences in symptom severity can be seen as support for the single syndrome hypothesis. On the other hand, the existence of discrete syndromes could not be ruled out because of reliable differences between CFS and CFS/FM. Increasing comorbidity was associated with a corresponding increase in risk of major depression.

Adult↗
PubMed2005

Hypothalamo-pituitary-adrenal gland axis in mice inhaling toluene prior to low-level long-term exposure to formaldehyde.

We studied the change in the hypothalamo-pituitary-adrenal gland (HPA) axis upon adding prior toluene inhalation to our previous formaldehyde inhalation experiments to determine whether short term exposure to relatively high levels of toluene triggers multiple chemical sensitivity (MCS). Data come from immunocytochemical, morphometrical and RT-PCR measurements. Four groups of adult female mice were exposed to differing concentrations (0, 80, 400, and 2,000 ppb) of formaldehyde for 16 hr/day, 5 days/week for twelve weeks, after the mice were exposed intranasally to 500 ppm toluene per mouse for 6 hr/day, for 3 days. We found that the number of corticotropin releasing hormone (CRH)-immunoreactive (ir) neurons was up-regulated according to the amount of formaldehyde as well as inhalation of formaldehyde alone in our previous experiment. The proportion of adrenocorticotropin hormone (ACTH)-ir cells increased according to the formaldehyde concentration, though there was no significant difference between the 400 and 2,000 groups. The number of ACTH-ir cells was higher in the 400 group than in the other groups (0, 80, and 2,000). Expression of ACTH-mRNA was also up-regulated according to the quantity of formaldehyde. The sinusoid in the anterior pituitary showed more dilatation in the 400 and 2,000 groups than in the control group, especially in the 2,000 group. We propose that exposure to toluene prior to inhalation of formaldehyde has no effect on the HPA axis and as a trigger of MCS, although greater sinusoid dilatation was found in the anterior pituitary gland at higher concentrations of formaldehyde.

Administration, Inhalation↗
PubMed2001

Exposure to repeated low-level formaldehyde in rats increases basal corticosterone levels and enhances the corticosterone response to subsequent formaldehyde.

Low-level exposure to volatile organic compounds may produce symptoms in humans reporting multiple chemical sensitivity (MCS) through altered hypothalamic-pituitary-adrenal (HPA) axis functioning. We determined whether repeated formaldehyde (Form) exposure would alter corticosterone (CORT) levels in a rat model of MCS. Male Sprague-Dawley rats were given acute chamber exposures to Air or Form (0.7 or 2.4 ppm), and trunk blood was collected 20 or 60 min later. All groups showed increased CORT levels above naïve basal levels at 20 min and a return to baseline by 60 min, with no differences between treatment groups. The second experiment examined the effect of repeated Form exposure (1 h/day x 5 days/week x 2 or 4 weeks) on basal CORT levels and after a final challenge. Basal CORT was increased above naïve values after 2 week exposure to Air or 0.7 ppm Form. By 4 week, CORT levels in the Air group returned to naïve values, but remained elevated in the 0.7 ppm Form group. There were no differences in basal CORT levels among either 2.4 ppm exposed groups. After a final Air or Form challenge, the 2 and 4 week Air and 0.7 ppm Form groups had elevated CORT levels similar to their acute response, while the 2 and 4 week 2.4 ppm Form groups had elevated CORT levels compared to their acute response, indicating enhanced reactivity of the HPA axis to subsequent Form. These findings suggest that altered HPA axis functioning occurs after repeated low-level Form exposure, and may have implications for mechanisms mediating MCS in humans.

Animals↗
PubMedDate not supplied

EEG sensitization during chemical exposure in women with and without chemical sensitivity of unknown etiology.

This study tested the sensitization model proposed by Bell et al. [Bell I.R., Miller C.S. and Schwartz G.E. An olfactory-limbic model of multiple chemical sensitivity syndrome: possible relationship to kindling and affective spectrum disorders. Biol. Psychiatry 1992: 32: 218-242] to study chemical sensitivity. The sensitization model indicates that a pharmacological stimulus or a traumatic event which elicits a strong response can sensitize limbic and/or mesolimbic pathways; and subsequent less intense trauma or stimuli, in the same or different modality, can elicit an amplified response. Three groups of subjects were tested: (1) women who reported chemical sensitivity and no sexual abuse (chemically sensitive, CS); (2) sexually abused (SA) women without chemical sensitivity; and (3) healthy women without chemical sensitivity or sexual abuse history (normal, N). All subjects were exposed to odorant and nonodorous control stimuli once a week for 3 weeks. Electroencephalographic activity was recorded while subjects sniffed the odorant and control stimuli. Results of the study revealed that both the CS and the SA group showed electroencephalogram (EEG) alpha sensitization across experimental sessions, while the N group showed little change over time. Additionally, EEG findings revealed that the CS group generated significantly greater alpha activity than the other two groups. Finally, while the groups were different on measures of psychological distress, these differences did not diminish the EEG findings. In summary, these findings suggest that intermittent exposure to chemicals elicits sensitization in CS and SA women without chemical sensitivity, supporting our expectations that chemical sensitivity is, in part, a manifestation of time-dependent sensitization (TDS). Additionally, these EEG findings indicate that CS women are unlike SA and healthy women in the amount of EEG alpha activity they generate. Finally, these findings indicate that psychological factors as assessed in this study do not explain electrophysiological differences between chemically and non-chemically-sensitive women.

Drug Hypersensitivity↗
PubMed1998

Illness from low levels of environmental chemicals: relevance to chronic fatigue syndrome and fibromyalgia.

This article summarizes (1) epidemiologic and clinical data on the symptoms of maladies in association with low-level chemicals in the environment, i.e., environmental chemical intolerance (CI), as it may relate to chronic fatigue syndrome (CFS) and fibromyalgia; and (2) the olfactory-limbic neural sensitization model for CI, a neurobehavioral synthesis of basic and clinical research. Severe CI is a characteristic of 20-47% of individuals with apparent CFS and/or fibromyalgia, all patients with multiple chemical sensitivity (MCS), and approximately 4-6% of the general population. In the general population, 15-30% report at least minor problems with CI. The levels of chemicals reported to trigger CI would normally be considered nontoxic or subtoxic. However, host factors--e.g., individual differences in susceptibility to neurohormonal sensitization (amplification) of endogenous responses--may contribute to generating a disabling intensity to the resultant multisystem dysfunctions in CI. One site for this amplification may be the limbic system of the brain, which receives input from the olfactory pathways and sends efferents to the hypothalamus and the mesolimbic dopaminergic [reward] pathway. Chemical, biologic, and psychological stimuli can initiate and elicit sensitization. In turn, subsequent activation of the sensitized limbic and mesolimbic pathways can then facilitate dysregulation of behavioral, autonomic, endocrine, and immune system functions. Research to date has demonstrated the initiation of neurobehavioral sensitization by volatile organic compounds and pesticides in animals, as well as sensitizability of cardiovascular parameters, beta-endorphin levels, resting EEG alpha-wave activity, and divided-attention task performance in persons with CI. The ability of multiple types of widely divergent stimuli to initiate and elicit sensitization offers a new perspective on the search for mechanisms of illness in CFS and fibromyalgia with CI.

Controlled Clinical Trials as Topic↗
PubMed1991

Approaches for assessing health risks from complex mixtures in indoor air: a panel overview.

Critical to a more definitive human health assessment of the potential health risks from exposure to complex mixtures in indoor air is the need for a more definitive clinical measure and etiology of the health effects of complex mixtures. This panel overview highlights six of the eight presentations of the conference panel discussion and features a number of the major topical areas of indoor air concern. W. G. Meggs assessed clinical research priorities with primary focus on the role of volatile organic chemicals in human health, recognizing the areas where definitive data are lacking. By recognizing many types of chemical sensitivity, it may be possible to design studies that can illuminate the mechanisms by which chemical exposure may cause disease. The critically important topic of multiple chemical sensitivity was discussed by N. A. Ashford, who identified four high risk groups and defined the demographics of these groups. P. A. Schulte addressed the issue of biological markers of susceptibility with specific considerations of both methodological and societal aspects that may be operative in the ability to detect innate or inborne differences between individuals and populations. Three case studies were reviewed. H. Anderson discussed the past and present priorities from a public health perspective, focusing on those issues dealing with exposures to environmental tobacco smoke and formaldehyde off-gassing from materials used in mobile home construction. J. J. Osborne described several case studies involving wood smoke exposure to children, with emphasis on the significantly greater occurrence of chronic respiratory symptoms and acute chest illness for children from homes heated with woodburning stoves.(ABSTRACT TRUNCATED AT 250 WORDS)

Air Pollution, Indoor↗
PubMed1996

Psychiatric aspects of air pollution.

Psychological and toxic effects of air pollution can lead to psychiatric symptoms, including anxiety and changes in mood, cognition, and behavior. Increased levels of some air pollutants are accompanied by an increase in psychiatric admissions and emergency calls and, in some studies, by changes in behavior and a reduction in psychological well-being. Numerous toxic pollutants interfere with the development and adult functioning of the nervous system. Manifestations are often insidious or delayed, but they can provide a more sensitive indicator of toxic effects than cancer rates or mortality data. Other medical effects of air pollution, such as asthma, can indirectly affect psychological health. The sick building syndrome and multiple chemical sensitivity are conditions with toxicologic and psychiatric aspects. Psychosocial stress can cause symptoms similar to those of organic mental disorders. Reactions to stress depend on cultural, individual, and situational variables. We must understand these factors to be able to alleviate and prevent the consequences of environmental trauma. Expanded research is recommended in three main areas: (1) how people perceive and cope with environmental health risks, (2) the effects of air pollution on behavior and neuropsychological functioning, and (3) neurotoxicologic evaluation of air pollutants with both behavioral and in vitro studies.

Adaptation, Psychological↗
PubMed1999

Organic solvents and time-dependent sensitization.

The nervous system is main target of the toxic action of most of organic solvents. There is little doubt that occupational solvent exposure may result in persisting neurobehavioural disturbances--the organic solvent syndrome. Recently, the solvents are quoted among possible causes of the abnormal condition referred to as multiple chemical sensitivity (MCS), and which is characterized by a psychosomatic over-reactivity to a variety of chemicals present in food or ambient air. According to some authors, MCS is a manifestation of the time-dependent sensitization (TDS), a phenomenon of progressive increase in responsiveness to chemical agents following acute or intermittent exposure, and related to some functional aberrations within limbic structures. TDS is commonly induced by psychostimulant drugs. The purpose of the present paper was to show, based on the literature data, that under circumstances of acute and repeated exposure, some solvents (mainly toluene) exert effect on behaviour and on the functional state of some neurotransmitter systems similar to that exerted by drugs known to induce TDS. Of special importance is the fact that in case of solvents the behavioural and biochemical changes suggestive of sensitization appear after exposure at levels close to those admissible in the occupational exposure, and that the concentration-effect relationship is nonlinear (an inverted U curve). To date, however, only a few of the existing data may be regarded as a direct evidence of the solvent-induced TDS. It is mainly due to the fact that the experimental protocol of a TDS study does not match the experimental routine of neurotoxicity assessment. Some data suggest that some solvents are possibly unable to induce TDS. The necessity to assess the commonly used solvents for their ability to induce TDS has been emphasized.

Animals↗
PubMed1993

Neurogenic inflammation and sensitivity to environmental chemicals.

Neurogenic inflammation as a pathway distinct from antigen-driven, immune-mediated inflammation may play a pivotal role in understanding a broad class of environmental health problems resulting from chemical exposures. Recent progress in understanding the mediators, triggers, and regulation of neurogenic inflammation is reviewed. Evidence for and speculations about a role for neurogenic inflammation in established disorders such as asthma, rhinitis, contact dermatitis, migraine headache, and rheumatoid arthritis are presented. The sick building syndrome and multiple chemical sensitivity syndrome have been defined as clinical entities in which exposure to chemical inhalants gives rise to disease. Current data on the existence of chemical irritant receptors in the airway and skin are discussed; neurogenic inflammation arising from stimulation of chemical irritant receptors is a possible model to explain many of the aspects of chemical sensitivities.

Air Pollutants↗
PubMed2003

Chronic diffuse musculoskeletal pain, fibromyalgia and co-morbid unexplained clinical conditions.

This chapter reviews our current knowledge on the presence of overlapping syndromes in one form of chronic diffuse pain, fibromyalgia. Patients with fibromyalgia often present with signs and symptoms of other unexplained clinical conditions, including chronic fatigue syndrome, irritable bowel syndrome, temporomandibular disorders, and multiple chemical sensitivities. The high prevalence, impact on function and opportunities for treatment underscore the need for clinicians and researchers to screen routinely for co-morbid unexplained clinical conditions among persons with fibromyalgia. We, therefore, describe a simple approach to screening for such conditions in accordance with published criteria. Interventions should directly address both fibromyalgia symptoms and co-morbid unexplained clinical conditions, as well as the multiple factors that propagate pain, fatigue and limitations in function.

Chronic Disease↗
PubMed1999

Psychiatric diagnoses in Gulf War veterans with fatiguing illness.

The purpose of this study was to determine whether Gulf War Illness (GWI) can be explained by the presence of psychiatric disorders as assessed by DSM-III-R. To reduce the heterogeneity amongst Persian Gulf War veterans with GWI (PGV-F), only those were studied who presented with severe fatigue as a major complaint and also fulfilled clinical case definitions for Chronic Fatigue Syndrome, Idiopathic Chronic Fatigue, and/or Multiple Chemical Sensitivity. A total of 95 Registry PGVs were examined; 53 presented with GWI and 42 did not report any post-war health problems (PGV-H). All subjects were assessed for the presence of DSM-III-R Axis I psychiatric disorders. Compared to PGV-Hs, 49% of PGV-Fs had similar post-war psychiatric profiles: either no, or only one, psychiatric disorder was diagnosed. Psychiatric profiles of the remaining 51% of PGV-Fs were significantly different from PGV-Hs in that most of these veterans suffered from multiple post-war psychiatric diagnoses. The presence of psychiatric disorders as assessed by DSM-III-R criteria cannot explain symptoms of Gulf War Illness among all Persian Gulf veterans with severe fatiguing illness.

Adult↗
PubMed2004

Subjective health complaints, sensitization, and sustained cognitive activation (stress).

INTRODUCTION: This review argues that "subjective health complaints" is a better and neutral term for "unexplained medical symptoms." The most common complaints are musculoskeletal pain, gastrointestinal complaints and "pseudoneurology" (tiredness, sleep problems, fatigue, and mood changes). These complaints are common in the general population, but for some these complaints reach a level that requires care and assistance. THEORETICAL ASSUMPTIONS: We suggest that these complaints are based on sensations from what in most people are normal physiological processes. In some individuals these sensations become intolerable. In some cases it may signal somatic disease, in most cases not. Cases without somatic disease, or with minimal somatic findings, occur under diagnoses like burnout, epidemic fatigue, multiple chemical sensitivity, chronic musculoskeletal pain, chronic low back pain, chronic fatigue syndrome, and fibromyalgia. These complaints are particularly common in individuals with low coping and high levels of helplessness and hopelessness. CONCLUSION: The psychobiological mechanisms for this is suggested to be sensitization in neural loops maintained by sustained attention and arousal.

Cognition↗