Tag: Gulf War Illness

Potential mechanisms in chemical intolerance and related conditions

Abstract:

The symptom of chemical intolerance may occur in isolation, but often occurs in conjunction with other chronic symptoms such as pain, fatigue, memory disturbances, etc. This frequent clustering of symptoms in individuals has led to the definition of several chronic multisymptom syndromes, such as multiple chemical sensitivity, fibromyalgia, chronic fatigue syndrome, and Gulf War illnesses. The aggregate research into these syndromes has suggested some unifying mechanisms that contribute to symptomatology. Multiple lines of evidence suggest that there is aberrant function of numerous efferent neural pathways, such as the autonomic nervous system and hypothalamic-pituitary axes, in subsets of individuals with these conditions.

There is perhaps the greatest evidence for abnormal sensory processing in these syndromes, with a low “unpleasantness threshold” for multiple types of sensory stimuli. Psychological and behavioral factors are known to play a significant role in initiating or perpetuating symptoms in some persons with these illnesses. In the field of pain research, the interrelationship between physiologic and psychologic factors in symptom expression has been well studied. Using both established and novel methodologies, studies have suggested that psychologic factors such as hypervigilance and expectancy are playing a relatively minor role in most individuals with fibromyalgia and that clear evidence exists of physiologic amplification of sensory stimuli.

These studies need to be extended to more sensory tasks and to larger numbers of subjects with related conditions. It is of note, though, that existing data on this spectrum of illnesses would suggest that there may be greater psychologic contributions to symptomatology if an illness is defined in part by behavior (e.g., avoidance of chemical exposures) rather than on the basis of symptoms alone.

 

Source: Clauw DJ. Potential mechanisms in chemical intolerance and related conditions.  Ann N Y Acad Sci. 2001 Mar;933:235-53. http://www.ncbi.nlm.nih.gov/pubmed/12000024

 

Cytokines and chronic fatigue syndrome

Abstract:

Chronic fatigue syndrome (CFS) patients show evidence of immune activation, as demonstrated by increased numbers of activated T lymphocytes, including cytotoxic T cells, as well as elevated levels of circulating cytokines. Nevertheless, immune cell function of CFS patients is poor, with low natural killer cell cytotoxicity (NKCC), poor lymphocyte response to mitogens in culture, and frequent immunoglobulin deficiencies, most often IgG1 and IgG3.

Immune dysfunction in CFS, with predominance of so-called T-helper type 2 and proinflammatory cytokines, can be episodic and associated with either cause or effect of the physiological and psychological function derangement and/or activation of latent viruses or other pathogens. The interplay of these factors can account for the perpetuation of disease with remission/exacerbation cycles. A T-helper type 2 predominance has been seen among Gulf War syndrome patients and this feature may also be present in other related disorders, such as multiple chemical sensitivity. Therapeutic intervention aimed at induction of a more favorable cytokine expression pattern and immune status appears promising.

 

Source: Patarca R. Cytokines and chronic fatigue syndrome.  Ann N Y Acad Sci. 2001 Mar;933:185-200. http://www.ncbi.nlm.nih.gov/pubmed/12000020

 

Neurobehavioral deficits associated with chronic fatigue syndrome in veterans with Gulf War unexplained illnesses

Abstract:

Gulf War unexplained illnesses (GWUI) are a heterogeneous collection of symptoms of unknown origin known to be more common among veterans of the Gulf War than among nonveterans. In the present study we focused on one of these unexplained illnesses.

We tested the hypothesis that in a sample of Persian Gulf War veterans chronic fatigue syndrome (CFS) was associated with cognitive deficits on computerized cognitive testing after controlling for the effects of premorbid cognitive differences. We obtained Armed Forces Qualification Test (AFQT) data acquired around the date of induction into the military on 94 veterans of the Gulf War, 32 with CFS and 62 healthy controls. Controls performed better than participants diagnosed with CFS on the AFQT. Cognitive deficits were associated with CFS on 3 of 8 variables after the effect of premorbid AFQT scores was removed with ANCOVA.

 

Source: Binder LM, Storzbach D, Campbell KA, Rohlman DS, Anger WK; Members of the Portland Environmental Hazards Research Center. Neurobehavioral deficits associated with chronic fatigue syndrome in veterans with Gulf War unexplained illnesses. J Int Neuropsychol Soc. 2001 Nov;7(7):835-9. http://www.ncbi.nlm.nih.gov/pubmed/11771626

 

Symptom factor analysis, clinical findings, and functional status in a population-based case control study of Gulf War unexplained illness

Abstract:

Few epidemiological studies have been conducted that have incorporated clinical evaluations of Gulf War veterans with unexplained health symptoms and healthy controls. We conducted a mail survey of 2022 Gulf War veterans residing in the northwest United States and clinical examinations on a subset of 443 responders who seemed to have unexplained health symptoms or were healthy. Few clinical differences were found between cases and controls.

The most frequent unexplained symptoms were cognitive/psychological, but significant overlap existed with musculoskeletal and fatigue symptoms. Over half of the veterans with unexplained musculoskeletal pain met the criteria for fibromyalgia, and a significant portion of the veterans with unexplained fatigue met the criteria for chronic fatigue syndrome. Similarities were found in the clinical interpretation of unexplained illness in this population and statistical factor analysis performed by this study group and others.

 

Source: Bourdette DN, McCauley LA, Barkhuizen A, Johnston W, Wynn M, Joos SK, Storzbach D, Shuell T, Sticker D. Symptom factor analysis, clinical findings, and functional status in a population-based case control study of Gulf War unexplained illness. J Occup Environ Med. 2001 Dec;43(12):1026-40. http://www.ncbi.nlm.nih.gov/pubmed/11765674

 

Chemical sensitivity and chronic fatigue in Gulf War veterans: a brief report

Abstract:

The foci of this brief report are to (1) describe the prevalence of chemical sensitivity (CS) and chronic fatigue (CF) symptomatology and of presumptive multiple CS and CF syndrome diagnoses, and (2) explore the potential overlap between one purported case definition (i.e., chronic multi-symptom illness) and these unexplained symptom syndromes in a well-characterized group of Gulf War veterans. The number of subjects with CS and CF symptomatology and presumptive multiple CS and CF syndrome diagnoses was higher in the Gulf War-deployed group compared with a group deployed to Germany during the Gulf War. However, the percent differences were not significant when comparing the presumptive diagnoses of multiple CS and CF syndrome. The characteristic differences between the groups and the overlap with chronic multi-symptom illness are also discussed.

 

Source: Proctor SP, Heaton KJ, White RF, Wolfe J. Chemical sensitivity and chronic fatigue in Gulf War veterans: a brief report. J Occup Environ Med. 2001 Mar;43(3):259-64. http://www.ncbi.nlm.nih.gov/pubmed/11285874

 

Multiple chemical sensitivity and chronic fatigue syndrome in British Gulf War veterans

Abstract:

The objective of this study was to measure the prevalence of multiple chemical sensitivity (MCS) and chronic fatigue syndrome (CFS) in British Gulf War veterans and to investigate their association with reported exposures and psychologic morbidity. In 1997–1998, the authors undertook a cross-sectional survey of three cohorts of British military personnel comprising Gulf veterans (n = 3,531), those who had served in Bosnia (n = 2,050), and those serving during the Gulf War but not deployed there (Era cohort, n = 2,614). MCS and CFS were defined according to operational criteria.

The prevalence of MCS in the Gulf, Bosnia, and Era cohorts was 1.3%, 0.3%, and 0.2%, respectively. For CFS, the prevalence was 2.1% (Gulf cohort), 0.7% (Bosnia cohort), and 1.8% (Era cohort). In Gulf veterans, MCS was strongly associated with exposure to pesticides (adjusted odds ratio = 12.3, 95% confidence interval: 5.1, 30.0). Both syndromes were associated with high levels of psychologic morbidity.

These findings suggest that CFS and MCS account for some of the medically unexplained illnesses reported by veterans after deployment to the Gulf. MCS was particularly associated with Gulf deployment and self-reported exposure to pesticides, findings that merit further exploration given the controversial status of this diagnosis and the potential for recall bias in a questionnaire survey.

 

Source: Reid S, Hotopf M, Hull L, Ismail K, Unwin C, Wessely S. Multiple chemical sensitivity and chronic fatigue syndrome in British Gulf War veterans. Am J Epidemiol. 2001 Mar 15;153(6):604-9. http://aje.oxfordjournals.org/content/153/6/604.long (Full article)

 

Toxicant-induced loss of tolerance

Abstract:

Drug addiction and multiple chemical intolerance (abdiction) appear to be polar opposites–the former characterized by craving and dependency, the latter by aversion. However, when the two are viewed in juxtaposition similarities emerge, revealing a common underlying dynamic, one which appears to be a new paradigm of disease. TILT, or toxicant-induced loss of tolerance, bridges the gap between addiction and abduction and has the potential to explain a variety of illnesses, including certain cases of asthma, migraine headaches and depression, as well as chronic fatigue syndrome, fibromyalgia and “Gulf War syndrome”.

This paper argues that both addiction and chemical intolerance involve a fundamental breakdown in innate tolerance, resulting in an amplification of various biological effects, particularly withdrawal symptoms. While addicts seek further exposures so as to avoid unpleasant withdrawal symptoms, chemically intolerant individuals shun their problem exposures, but for the same reason–to avoid unpleasant withdrawal symptoms.

These observations raise critical questions: do addictive drugs and environmental pollutants initiate an identical disease process? Once this process begins, can both addictants and pollutants trigger symptoms and cravings? TILT opens a new window between the fields of addiction and environmental medicine, one that has the potential to transform neighboring realms of medicine, psychology, psychiatry and toxicology.

 

Source: Miller CS. Toxicant-induced loss of tolerance. Addiction. 2001 Jan;96(1):115-37. http://www.ncbi.nlm.nih.gov/pubmed/11177524

 

Stressors, personality traits, and coping of Gulf War veterans with chronic fatigue

Abstract:

OBJECTIVES: preliminary surveys of Persian Gulf veterans revealed a significant prevalence of self-reported symptoms consistent with chronic fatigue syndrome (CFS). The purpose of this study was to compare self-reported life stressors, combat, and chemical exposures, personality and coping between Gulf War veterans with CFS and healthy veterans.

METHODS: following a complete physical, psychiatric, and neuropsychological evaluation, 45 healthy veterans, 35 veterans with CFS and co-morbid psychiatric disorder, and 23 veterans with CFS and no co-morbid psychiatric disorder completed questionnaires assessing war and non-war-related life stressors, self-reports of environmental exposure (e.g. oil well fires, pesticides), personality, and coping.

RESULTS: measures of personality, self-reported combat and chemical exposures, and negative coping strategies significantly differentiated healthy veterans from those with CFS.

CONCLUSION: a biopsychosocial model of veterans’ illness was supported by the fact that personality, negative coping strategies, life stress after the war, and environmental exposures during the war were significant predictors of veterans’ current physical function.

 

Source: Fiedler N, Lange G, Tiersky L, DeLuca J, Policastro T, Kelly-McNeil K, McWilliams R, Korn L, Natelson B. Stressors, personality traits, and coping of Gulf War veterans with chronic fatigue. J Psychosom Res. 2000 Jun;48(6):525-35. http://www.ncbi.nlm.nih.gov/pubmed/11033371

 

Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome

Abstract:

Fibromyalgia and widespread pain were common in Gulf War veterans with unexplained illness referred to a rheumatology clinic. Increased tenderness was demonstrated in the postmenstrual phase of the cycle compared with the intermenstrual phase in normally cycling women but not in users of oral contraceptives. Patients with fibromyalgia had high levels of symptoms that have been used to define silicone implant-associated syndrome. Tender points were found to be a common transient finding associated with acute infectious mononucleosis, but fibromyalgia was an unusual long-term outcome. The common association of fibromyalgia with other rheumatic and systemic illnesses was further explored. A preliminary study revealed a possible linkage of fibromyalgia to the HLA region. Patients with fibromyalgia were found to have an impaired ability to activate the hypothalamic pituitary portion of the hypothalamic pituitary adrenal axis as well as the sympathoadrenal system, leading to reduced corticotropin and epinephrine response to hypoglycemia. Much interest has been expressed in the literature on the possible role of autonomic dysfunction in the development or exacerbation of fatigue and other symptoms in chronic fatigue syndrome. Mycoplasma genus and mycoplasma fermentans were detected by polymerase chain reaction in patients with chronic fatigue syndrome. It was reported that myofascial temporomandibular disorder does not run in families. No major therapeutic trials in fibromyalgia, chronic fatigue syndrome, or myofascial pain syndrome were reported over the past year. The effectiveness of cognitive behavioral therapy and behavior therapy for chronic pain in adults was emphasized. A favorable outcome of fibromyalgia and chronic fatigue syndrome in children and adolescents was reported.

 

Source: Buskila D. Fibromyalgia, chronic fatigue syndrome, and myofascial pain syndrome. Curr Opin Rheumatol. 2000 Mar;12(2):113-23. http://www.ncbi.nlm.nih.gov/pubmed/10751014

 

Neurally mediated hypotension in fatigued Gulf War veterans: a preliminary report

Abstract:

BACKGROUND: Many patients with chronic fatigue syndrome (CFS) have neurally mediated hypotension when subjected to head-up tilt, suggesting autonomic nervous system dysfunction. Some Gulf War veterans have symptoms similar to CFS. Whether they also tend to have neurally mediated hypotension is unknown.

METHODS: We performed 3-stage tilt-table testing on 14 Gulf War veterans with chronic fatigue, 13 unfatigued control Gulf War veterans, and 14 unfatigued control subjects who did not serve in the Gulf War. Isoproterenol was used in stages 2 and 3 of the tilt protocol.

RESULTS: More fatigued Gulf War veterans than unfatigued control subjects had hypotensive responses to tilt (P < 0.036). A positive response to the drug-free stage 1 of the tilt was observed in 4 of 14 fatigued Gulf War veterans versus 1 of 27 unfatigued control subjects (P < 0.012). Heart rate and heart rate variation during stage 1 was significantly greater in the fatigued group (P < 0.05).

CONCLUSION: We conclude that more fatigued Gulf War veterans have neurally mediated hypotension than unfatigued control subjects, similar to observations in CFS. Autonomic nervous system dysfunction may be present in some fatigued Gulf War veterans.

 

Source: Davis SD, Kator SF, Wonnett JA, Pappas BL, Sall JL. Neurally mediated hypotension in fatigued Gulf War veterans: a preliminary report. Am J Med Sci. 2000 Feb;319(2):89-95. http://www.ncbi.nlm.nih.gov/pubmed/10698092