Sandra K. McDonald Colorado State University Multiple Chemical Sensitivity An increased sensitivity to chemicals in the environment attributed to prior chemical exposure Multiple Chemical Senstivity
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Sandra K. McDonald Colorado State University Multiple Chemical Sensitivity An increased sensitivity to chemicals in the environment attributed to prior chemical exposure Multiple Chemical Senstivity Other names: Environmental illness (EI) Ecological illness Total allergy syndrome The 20th century disease (Hileman, 1991) Idiopathic environmental intolerances (IPCS, 1996) Multiple Chemical Sensitivity Term most commonly applied to a condition that challenges patients, health-care providers & health & environmental agencies alike Multiple Chemical Sensitivity In broad terms it means an unusually severe sensitivity or allergy-like reaction to many different kinds of pollutants including : Solvents VOC's (Volatile Organic Compounds) Perfumes fuels Smoke "chemicals" in general MCS – Do We Understand? The idiopathic or "not understood" nature of MCS means that doctors & others are often highly skeptical about the reality of – and nature of - the MCS condition Many features of MCS and it’s effects and the way it’s effects are described by the sufferer seem altogether unrealistic, impossible or implausible to a conventional & scientifically trained consultant or General Practitioner MCS First Report Theron Randolph, 1952 Physician trained in allergy & immunology Reported a number of patients reacted adversely to chemicals in their environment MCS First Report Linked the adverse effects of this "petrochemical problem" to contact with chemicals found in commonly encountered substances i.e., cosmetics, auto fuels, exhaust fumes & food additives MCS First Report Observed that many patients reacted to many industrial solvents found in small amounts in manufactured products such as construction materials, newspaper & other ink-related products, furniture & carpet American Academy of Environmental Medicine Randolph, 1965, founded Society for Human Ecology In response to this lack of acceptance within his specialty 1985, name changed to the American Academy of Environmental Medicine Environmental physicians MCS Definitions Cullen’s (1987) definitions is widely used – four elements: syndrome is acquired after a documentable environmental exposure that may have caused objective evidence of health effects; 2. symptoms are referable to multiple organ systems and vary predictably in response to environmental stimuli; 3. symptoms occur in relation to measurable levels of chemicals, but the levels are below those known to harm health; and 4. no objective evidence of organ damage can be found. 1. MCS Definitions Cullen’s definition has the practical advantage of describing a syndrome without specifying individual symptoms or mechanisms of disease Multiple Chemical Sensitivity Wide variety of symptoms have been reported (Terr, 1986; Lax & Henneberger, 1995) Symptoms of MCS Extreme fatigue Headache Gastrointestinal problems Muscle & joint pain Depression Memory & concentration difficulties Anxiety Upper airway irritation Multiple Chemical Sensitivity Patients have associated their symptoms with many substances (Ziem, 1992; Lax & Henneberger, 1995) Exposures linked to MCS Carpet & upholstery materials Construction materials Deodorizers Disinfectants Fabrics Newspapers Paint Perfumed ‘personal’ products Pesticides Petroleum products Plastics Wood preservatives Multiple Chemical Sensitivity Persons reported as suffering from MCS present with outcomes that range from minor discomfort to severe disability Americans with Disability Act In 1991, multiple chemical sensitivity was defined as a disability under the act Resulted in the demand for accommodation at work, at school and in housing for those with a diagnosis of MCS In some states, MCS is recognized under workers' compensation laws as a disability resulting in free health care for persons with symptoms related to the phenomenon, as well as payment for lost wages Because a major treatment recommendation is avoidance of chemical exposure, the worker may never return to active employment OSHA’s View on MCS www.osha.gov/SLTC/multiplechemicalsensitivities/index. html MCS is a highly controversial issue In theory, MCS is an adverse physical reaction to low levels of many common chemicals Chemical sensitivity is generally accepted as a reaction to chemicals but debate continues as to whether MCS is classifiable as an illness Proposed Mechanisms Theories of the etiology of MCS can be grouped into four broad categories: Physical Stress Misdiagnosis Illness belief Sparks 1994 Physical Three basic physical mechanisms have been proposed to explain MCS: Allergy Direct toxic effects Neurobiologic sensitization Simon 1993 Allergy Chemical ecology movement believes chemical exposure causes the development of allergy to low levels of many chemicals, not just the initiating one Supporters point to a spectrum of immune system tests that have been found to be abnormal in patients with MCS Multiple Chemical Sensitivity Patients react to extremely tiny amounts of chemicals Only mechanism which is now known to cause reaction to tiny amounts is antibody formation (i.e., allergy) Some MCS patients react to chemicals which do not induce formation of antibodies Multiple Chemical Sensitivity True allergies - where the underlying mechanisms of the problem are relatively well understood widely accepted MCS , is generally regarded as "idiopathic" - meaning that it has no known mechanism of causation & it's processes are not fully understood The problem here is made more difficult still, due to the variable nature of Multiple Chemical Sensitivity from one patient to the next & this often makes treatment with conventional medicine & practices ineffective or inappropriate; for most sufferers with Multiple Chemical Sensitivity, the avoidance of pollutants/toxicants is the key. True Allergy An acquired reaction caused by an immune system response to one SPECIFIC excitant that has already been encountered at least once before Miniscule Dose of a Toxicant Sensitization is a true allergic reaction to one chemical or irritant and is caused by involvement within the body of mast cells and IgE antibodies Once sensitized to a particular irritant, a subsequent exposure to even a tiny amount of the same irritant even parts per million – ppm – or parts per billion – ppb can cause an extreme allergic reaction one ppm = 0.0001 % Toxicological Effects Others propose a toxicological effect of low- dose exposure -- poisoning Objective evidence for such an effect is lacking Patients with MCS experience symptoms at levels of chemical exposure far lower than those considered toxic Multiple Chemical Sensitivity Miller et al. (1997) Theory of "toxicant-induced loss of tolerance" (TILT) Acute or chronic chemical exposures might cause certain susceptible persons to lose their tolerance for previously tolerated chemicals, drugs & foods Subsequently, even minute quantities of these & other substances may trigger symptoms Neurobiological Sensitization Affected persons develop increasing neurologic sensitivity to the adverse effects of chemicals Animal models for such neurologic changes include limbic kindling and time-dependent neurologic sensitization These events have been documented only with pharmacologic doses and only in animals, not in humans and not at the low doses purported to cause MCS Sensitivity This sensitivity, in the case of MCS, to unrelated toxicants does, however, have several unproven, but seemingly sound theories to explain it including: Enzyme depletion Conditioning Immune system disorders Enzyme Depletion Enzymes are also used to detoxify a wide range of synthetic chemicals If the enzymes are depleted or damaged by health problems, then they are unable to metabolize these toxicants efficiently, so leading to the problems associated with MCS Many types of enzyme deficiency can be inherited Some (fairly tentative) evidence to suppose that MCS may affect other members of the same family Conditioning Two unrelated events occur at the same time and one event becomes associated with the other When the first event is later repeated, the second event also manifests itself for the sufferer For example, if on a particular day the patient is already feeling slightly unwell and if, coincidentally, the patient is exposed to (say) paint fumes, then the paint fumes may genuinely make the patient feel unwell and possibly nauseous A subsequent exposure to the same paint fumes - or a similarly strong solvent odor - may produce a strong feeling of nausea for the patient, who, moments before, felt perfectly well Immune System Damage Some researchers are of the opinion that MCS is due to immune system damage or malfunction, which could give rise to a sensitivity to all sorts of triggers rather than a specific reaction to one toxicant Another important and debilitating feature of MCS - and which tends to complicate MCS diagnosis & treatment still further - is it's ability to apparently augment the effects of other problems experienced by the patient problems such as common allergies, asthma, depression, food intolerances etc, & these problems of augmentation are reported by about half of all MCS sufferers Sensitively Scepticism Main aspect of MCS sensitivity that is NOT fully understood is that the MSC sufferer reacts similarly and in an allergic fashion to a whole range of completely unrelated toxicants "chemicals“ Solvents Perfumes VOCs Odors etc. MCS Triggers Can change over time A person who was not reactive to a particular substance may or may not react when exposed to the same substance at a later time Vary between people Not all people react to all triggers MCS Epidemiology Most patients (85 -90 %) complaining of MCS syndrome are women Most present between the ages of 30 and 50 years The question of whether MCS is becoming more or less common is unanswered As is the question of whether it is preventable Avoidance of “Triggers” Patients often significantly alter their behavior in an attempt to avoid presumed precipitants of symptoms 97 % of the patients had stopped activities outside the home 91 % had limited their travel 89 % had limited their contact with friends 77 % had left a job Lax 1995 Avoidance of “Triggers” Many changed home routines: 97 % had stopped using cleaning compounds 69 % removed home furnishings 63 % limited their contact with family members In their personal care: 94 % stopped using fragrances 91 % changed their diet 86 % changed the type of clothing they wore Lax 1995 MCS Debate Validity of MCS as a distinct disease entity What role, if any, the biochemical mechanisms of specific chemicals have in the onset of this condition Multiple Chemical Sensitivity No diagnostic criteria for it No set of signs and symptoms which are always found in persons who believe they are chemically sensitive No objective blood or other laboratory test for MCS Who gets MCS? 5% of U.S. population has severe MCS Greatly reduced quality of life 15-30% have less severe problems Women four times as likely to be affected as men Average age of onset is during 40’s Coping with MCS No cure at present Treatment – avoid exposure Isolation General lack of acknowledgment of MCS within medical community MCS & Society Multiple chemical sensitivity is not simply a medical concern of diagnosis and treatment, but it is becoming a major social and economic issue with a strong activist agenda Chemical Sensitivity: The Truth About Environmental Illness (Barrett and Gots 1998) MCS & Society Advocates of multiple chemical sensitivity have successfully sought sympathy and support by attacking the chemical industry and others as the source of their plight Numerous activist organizations publish newsletters and maintain Web sites that identify physicians and lawyers who support the chemical causality of their illnesses A newsletter reports legislative, public policy and court decisions that support multiple chemical sensitivity as a legitimate disease or disability -- Our toxic times. Chemical Injury Information Network, White Sulphur Springs, Montana Debated Topics Whether MCS is a distinct disease entity Its etiology (or etiologies) Its pathophysiology How to define the condition How it should be treated How it should be approached in legal & legislative arenas Questions?