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At least 19 recordsLinked to original sources
PubMed1996

What can research contribute to regulatory decisions about the health risks of multiple chemical sensitivity?

Multiple Chemical Sensitivity (MCS), which may not be caused by chemicals at all, is a serious medical problem of unknown origin and uncertain etiology that raises many fundamental science and policy questions. Regulators, for example, are confronted with a dilemma: what, if anything, should be done to protect people from the scientifically uncertain health risks of exposures to extremely low levels of environmental chemicals. Regulatory agencies, such as the Environmental Protection Agency, do not have the luxury of waiting until conclusive scientific evidence is available before making a decision; however, our present lack of scientific understanding about MCS is so acute that it is not possible to ascertain whether the cause of MCS-related symptoms is chemical, biological, physical, psychosocial, or some combination thereof. Nevertheless, many MCS sufferers and advocates for the chemically induced hypothesis are clamoring for regulatory action to reduce putative health risks from very-low-level exposures to chemicals in the environment. Unless steps are taken to improve the quantity and quality of the existing scientific data base, we cannot, with any acceptable degree of certainty, evaluate the extent to which regulatory decisions about MCS are either protective of public health or cost-effective. This article examines how research can strengthen the scientific basis for risk-related decisions about MCS, and proposes a framework for establishing research directions and priorities. It is argued that high-priority research on MCS is distinguishable by four attributes: (1) results are valuable for risk-related decisions; (2) findings significantly advance scientific knowledge and understanding; and the hypothesis being tested is both (3) biologically plausible and (4) readily testable.

Decision Making↗
PubMed1997

Laboratory testing of the patient with multiple chemical sensitivity.

Multiple diagnostic laboratory tests are frequently used in the clinical evaluation of persons with multiple chemical sensitivity without a clear a priori hypothesis. In addition, many of these tests are performed despite a lack of understanding of the test technical performance characteristics or the clinical significance (test sensitivity and specificity). The result is a plethora of laboratory data that have little clinical relevance and that can be both misleading and misused.

Clinical Laboratory Techniques↗
PubMed1996

Medical management of the multiple chemical sensitivity patient.

Multiple chemical sensitivity (MCS) is a complex, chronic disorder characterized by multisystemic symptoms occurring in response to a wide variety of chemical odors or low-level exposures. The etiology is unknown but likely multifactorial. Patient evaluation includes a comprehensive history with a review of past medical records and a physical examination with specific attention to the affected organ systems. Laboratory evaluation is dependent on past testing and patient symptoms. It should be individualized and, although standard baseline tests are helpful, exhaustive testing is not. The evaluation is primarily designed to exclude diseases requiring specific medical therapy. Treatment approaches vary considerably depending on the treating physician and patient responsiveness; many have been adapted from those used for similar chronic illness of unknown etiology. Therapies utilized in MCS patients include supportive care, behavioral techniques, including desensitization, psychotherapy, chemical avoidance, and clinical ecology regimens such as provocation-neutralization protocols. The advantages and disadvantages of these approaches are discussed and the use of clinical ecology regimens is discouraged. A multidisciplinary approach similar to those used in chronic pain patients may be beneficial. Regardless of the treatment chosen, the goal should be to decrease patient disability.

Behavior Therapy↗
PubMed1997

Provocative challenges in patients with multiple chemical sensitivity.

Whether multiple chemical sensitivity (MCS) is an organic disease initiated by environmental exposure or a psychologic disorder is a subject of controversy. The identification of pathophysiologic or psychophysiologic mechanisms occurring in patients with MCS after provocative challenges should be illuminating. Fifteen patients with MCS were challenged with their trigger substances and observed clinically. Prechallenge and postchallenge pulmonary function tests and PCO2, PO2, and oxygen saturation were measured. All of the patients whose symptoms were reproduced by the challenge (11 of 15) showed clinical evidence of acute hyperventilation with a rapid fall in PCO2 and no change or a rise in oxygen saturation. The symptoms and signs were consistent with an anxiety reaction with hyperventilation. Pulmonary function was unchanged; and recovery was rapid, aided in two cases by rebreathing into a paper bag. The most logical conclusion is that in these patients the MCS disorder is a manifestation of an anxiety syndrome triggered by their perception of an environmental insult, with at least some of their symptoms induced by hyperventilation.

Adult↗
PubMed1995

[Multiple chemical sensitivity syndrome].

The multiple chemical sensitivity syndrome (MCS) is a novel constellation of symptoms in environmental medicine that has been extensively described and commented on in the USA. The main features of this syndrome are: multiple symptoms in different organ systems triggered by a variety of chemical substances, with relapses and exacerbations under certain precipitating circumstances at very low levels which do not cause any reactions in the population at large. There are no lab markers or specific investigative findings. This paper describes the historical development of the term MCS, its diagnostic criteria and pathophysiological aspects using 10 patient histories from our hospital.

Adult↗
PubMed1996

Neurobehavioral performance in multiple chemical sensitivities.

Individuals with Multiple Chemical Sensitivities (MCS) frequently report difficulties in attention/concentration, memory and accuracy and speed of problem solving. We evaluated neurobehavioral functioning in 35 chemically exposed patients referred to our Occupational and Environmental Neurology Clinic. Of these 35 patients, 17 presented with symptoms of MCS and 16 patients reported no symptoms of MCS. In addition, we used a group of 126 healthy controls for comparison. The performance of the MCS group was not significantly different from that of the control group on tests of verbal learning and memory, executive functioning, and psychomotor functioning. The MCS group performed below the control group on a test of visual learning and memory, but this performance was similar to the group with chemical exposure and no MCS. Therefore, performance on objective neurobehavioral tests did not confirm the most frequently reported subjective complaints of patients with MCS. These results suggests that patients with symptoms of MCS do not have compromised central nervous system functioning.

Adult↗
PubMed1996

Multiple chemical sensitivity multiorgan dysesthesia, multiple symptom complex, and multiple confusion: problems in diagnosing the patient presenting with unexplained multisystemic symptoms.

Patients are presenting in increasing numbers with multiorgan symptoms allegedly resulting from exposure to environmental chemicals. Among the symptoms expressed by patients with alleged multiple chemical sensitivities (MCS) are profound fatigue, mental confusion, myalgia, depression, anxiety, dizziness, headache, insomnia, loss of appetite, and numbness of the extremities, all in the absence of objective physical signs. Diagnostic criteria to assess the effects of environmental agents on organ systems are sorely needed because patients with MCS often have no tissue pathology or physiological abnormalities, but often do have diagnosable psychiatric illnesses. In treating patients with MCS, the physician should first perform a complete history and physical examination, including a comprehensive evaluation of chemical exposure. If the findings strongly suggest the presence of disease related to particular organ systems, further diagnostic evaluation should be undertaken. If abnormal findings are absent, psychiatric advice may be useful. The physician should keep an open mind about MCS but must also remember that a cause-effect relationship between exposure to multiple chemicals and symptoms has not been established.

Air Pollutants↗
PubMed1996

Multiple chemical sensitivities syndrome: a review.

Multiple chemical sensitivities (MCS) syndrome is a controversial diagnosis that has arisen in the latter half of the 20th century. Clinical ecologists strongly believe that multiple common environmental chemicals assault the immune system in certain individuals, producing multisystem disease. Mainstream medicine, however, largely believes that the symptoms of MCS syndrome can be attributed to a conditioned response to the environment and psychiatric disease. This review examines the controversy surrounding MCS syndrome in regard to the etiology, diagnosis, and management.

Environmental Exposure↗
PubMed1996

Potential animal model of multiple chemical sensitivity with cholinergic supersensitivity.

Multiple Chemical Sensitivity (MCS) is a clinical phenomenon in which individuals, after acute or intermittent exposure to one or more chemicals, commonly organophosphate pesticides (OPs), become overly sensitive to a wide variety of chemically-unrelated compounds, which can include ethanol, caffeine and other psychotropic drugs. The Flinders Sensitive Line (FSL) rats were selectively bred to be more sensitive to the OP diisopropylfluorophosphate (DFP) compared to their control counterparts, the Flinders Resistant Line (FRL) rats. The present paper will summarize evidence which indicates that the FSL rats exhibit certain similarities to individuals with MCS. In addition to their greater sensitivity to DFP, the FSL rats are more sensitive to nicotine and the muscarinic agonists arecoline and oxotremorine, suggesting that the number of cholinergic receptors may be increased, a conclusion now supported by biochemical evidence. The FSL rats have also been found to exhibit enhanced responses to a variety of other drugs, including the serotonin agonists m-chlorophenylpiperazine and 8-OH-DPAT, the dopamine antagonist raclopride, the benzodiazepine diazepam, and ethanol. MCS patients report enhanced responses to many of these drugs, indicating some parallels between FSL rats and MCS patients. The FSL rats also exhibit reduced activity and appetite and increased REM sleep relative to their FRL controls. Because these behavioral features and the enhanced cholinergic responses are also observed in human depressives, the FSL rats have been proposed as a genetic animal model of depression. It has also been reported that MCS patients have a greater incidence of depression, both before and after onset of their chemical sensitivities, so cholinergic supersensitivity may be a state predisposing individuals to depressive disorders and/or MCS. Further exploration of the commonalities and differences between MCS patients, human depressives, and FSL rats will help to elucidate the mechanisms underlying MCS and could lead to diagnostic approaches and treatments beneficial to MCS patients.

Animals↗
PubMed1997

Cognitive and psychomotor performance tests and experiment design in multiple chemical sensitivity.

People suffering from multiple chemical sensitivity (MCS) complain of a variety of symptoms that could impair cognitive and psychomotor function either directly or indirectly. This paper discusses the use of cognitive and psychomotor performance tests together with some experiment designs that could be considered for use to assess fitness of MCS sufferers for work or the efficacy of diagnostic, preventative, or therapeutic measures. The tests could also contribute to the body of objective information on MCS and help sway the opinion of those who are dubious of its authenticity. The credentials of cognitive and psychomotor performance tests are derived from their successful use in studying the effects of drugs, and the types of tests are illustrated by describing those used by the United Kingdom Defence Evaluation and Research Agency Chemical and Biological Defence Human Studies Group, which has been involved in the assessment of drugs and chemicals on work performance for many years. The tests include mathematical, verbal and spatial processing, tracking, reaction time, attention and vigilance, and memory tests. The discussion of experiment designs includes both repeated measures and parallel groups designs together with their advantages and disadvantages and some suggested modifications to accommodate the particular problems posed by MCS.

Cognition↗
PubMed1996

Neural sensitization and physiological markers in multiple chemical sensitivity.

This paper summarizes the key features of the olfactory-limbic, neural sensitization model for multiple chemical sensitivity (MCS) and presents relevant data on chemically intolerant human subjects from laboratory studies using quantitative electroencephalography, polysomnography, neuropsychological tests, cardiovascular measurements, and blood markers. MCS is a poorly understood chronic, polysymptomatic condition in which some prior controlled research studies have failed to find evidence to differentiate active from placebo tests. Closer examination of past MCS research, however, reveals that studies have failed to incorporate the design and methodological approaches necessary to test for nonimmunological sensitization. Time-dependent sensitization (TDS) is a well-documented phenomenon in the pharmacology literature involving the progressive increase in a given response by the passage of time between the initial and subsequent exposures to a substance or a stressor. As in MCS, multiple, chemically unrelated agents can trigger TDS. Females time-sensitize more readily than do males. Pharmacological and nonpharmacological (stress) stimuli can cross-sensitize. Dopaminergic pathways in the brain and the hypothalamic-pituitary-adrenal axis are likely involved in TDS. Data on the symptomatology of MCS point to central nervous system involvement, including limbic regions that receive input from both olfactory (odor) and trigeminal (irritant) pathways. Limbic and mesolimbic brain regions are among the most sensitizable to repeated, intermittent environmental stimuli. Sensitizable individuals can show no difference or lesser responses to a test substance on initial exposure, but later exhibit much greater increases in responsivity on the next exposure after a period of days. For future research, it is essential to distinguish chemical intolerance symptoms such as derealization, sudden mood changes, musculoskeletal pain, menstrual dysfunction, and uncontrollable sleepiness from chemical phobia and avoidance behaviors. This model permits hypothesis-driven research on MCS and has major implications for interpretation of apparently positive and negative tests for "true" as opposed to "perceived" sensitivity to low levels of environmental chemicals.

Humans↗
PubMedDate not supplied

Biological interventions in the treatment of patients with multiple chemical sensitivities.

The syndrome of multiple chemical sensitivities has many manifestations and undoubtedly many causes. Treatment must be individualized based on a thorough psychosocial and biological diagnostic evaluation. Careful listening, as is usually the case, not only results in a more complete history but also serves a critical therapeutic purpose in cementing a trusting, working partnership. Family dynamics, and larger social concerns, such as litigation, may figure importantly as obstacles to rehabilitation if they are ignored in treatment planning. In chronically disabled patients, the importance of psychosocial interventions is even greater but should not eclipse attention to relevant medical interventions. The most basic physiologic manipulation involves a program of environmental avoidance. Such a program should be applied with caution since it is not without risks of inadvertent exacerbation of medical and psychologic disabilities. Therefore, from a medical perspective, interventions should focus on improving chemical tolerance by the appropriate application of first aid, chronohygiene, nutrition, psychophysiology, and correction of microbiological disruptions. Thorough investigation for intercurrent disease and its appropriate management is paramount. Attempts to treat the entire problem by isolating attention to one area or based on a single theory are likely to fail.

Drug Tolerance↗
PubMed1996

[Multiple chemical sensitivity (MCS)--the so-called chemical multiple hypersensitivity].

Multiple chemical sensitivity syndrome (MCS) is believed to be a multiple organ disease caused by low-level exposure to chemical substances. It is characterized by central-nervous, gastrointestinal and irritative mucocutaneous symptoms. This phenomenon is not recognized in traditional medicine, opponents of the theory of a separate disease attributing all symptoms to psychopathological processes. Since this phenomenon is becoming increasingly prevalent in Western countries, appropriate strategies for its study need to be developed.

Diagnosis, Differential↗
PubMed1997

Human drug discrimination and multiple chemical sensitivity: caffeine exposure as an experimental model.

Multiple chemical sensitivity is a controversial diagnosis. Rigorous, controlled, laboratory-based research can reduce this controversy and lead to potential clinical confirmatory tests. The literature on human caffeine discrimination provides a rigorous methodology that can address reports that patients who suffer multiple chemical sensitivity (MCS) are sensitive to usually well-tolerated chemical doses; the studies require patients to discriminate caffeine from placebo under double-blind conditions. Several issues relevant to the conduct of caffeine discrimination studies using MCS patients as subjects are addressed; these issues include study design, determination of safe and tolerable training doses, and discrimination training. Such research will benefit patients and clinicians dealing with a diagnosis of MCS.

Caffeine↗
PubMed1997

Systematic considerations in the area of multiple chemical sensitivity.

Many workers who speculate about multiple chemical sensitivity (MCS) have devised a large number of hypothetical constructs designed to explain the phenomena. Too often these are not logically connected to the larger body of scientific thought but instead appeal to ideas not documented in accessible literature and often appearing metaphysical in nature.

Environmental Health↗
PubMed1995

Multiple chemical sensitivities--public policy.

The phenomenon of multiple chemical sensitivities is a peculiar manifestation of our technophobic and chemophobic society. It has been rejected as an established organic disease by the American Academy of Allergy and Immunology, the American Medical Association, the California Medical Association, the American College of Physicians, and the International Society of Regulatory Toxicology and Pharmacology. It may be the only ailment in existence in which the patient defines both the cause and the manifestations of his own condition. Despite this, it has achieved credibility in workmen's compensation claims, tort liability, and regulatory actions, all of which are briefly reviewed.

Humans↗
PubMed1996

Intranasal chemoreception in patients with multiple chemical sensitivities: a double-blind investigation.

Multiple chemical sensitivities (MCS) has become an increasingly frequent diagnosis assigned to patients with symptoms associated with exposures to environmental chemicals. Since the characteristic symptoms of MCS are triggered by very low concentrations of chemicals, in the range of olfactory thresholds, it is widely believed that the intranasal chemoreceptive senses are involved in the pathophysiology of MCS. Thus, the present study addressed both the olfactory and trigeminal systems: using a double-blind approach we investigated whether MCS patients show differences in responses after exposure to either room air or low concentrations of a widely used chemical agent (2-propanol). A total of 23 patients participated in the experiments (mean age 47 years; 13 female, 10 male). MCS was diagnosed according to Cullen's criteria Performance of the nasal chemical senses was established by means of chemosensory event-related potentials (CSERP) and subjective measures of olfactory function (odor discrimination, phenylethyl alcohol odor thresholds). CSERP were recorded in response to olfactory (H2S), and trigeminal (CO2) stimuli. The study provided three major results: (1) Approximately 20% of patients diagnosed with MCS presented symptoms regardless of the type of challenge, suggesting the susceptibility of MCS patients to unspecific experimental manipulations. (2) Changes in CSERP latencies indicated a change in the processing of both olfactory and trigeminal stimuli. (3) While odor threshold remained unchanged, the patients' ability to discriminate odors decreased after exposure to room air. In contrast, this decrease was less pronounced after exposure to 2-prop. Summarily, MCS patients respond to challenge with 2-prop with changes of chemosensory perception which might increase their susceptibility to environmentally volatile chemicals. Changes in the pattern of event-related potentials are interpreted as the possible change of the orientation of cortical generators, i.e., neuronal populations that were involved in the processing of chemosensory information. However, investigations in healthy controls are needed in order to draw further conclusions.

1-Propanol↗