Bioterrorism. Implications for the occupational and environmental health nurse

1. Bioterrorism is the intentional release of a biological agent--bacterial, viral, or genetically altered--to instill fear or create chaos, massive casualities, illness, and death in humans, animals, or plants. 2. The threat of bioterrorism is real. Although every community is vulnerable, terrorists seek densely populated, highly visible targets. 3. Occupational and environmental health nurses must to be able to recognize and report signs and symptoms of an early bioweapons outbreak in their workplaces and communities. Only thorough preparedness and planning will result in effective mitigation and treatment. 4. The Bioterrorism Readiness Plan (at http://www.apic.org and http://www.CDC.gov/ncidod/hip) is a template for health care professionals to help plan a realistic response to bioterrorism. It serves as a tool for successful collaboration and communication among all disciplines and public health agencies for the best possible outcomes.

Hepatic ultrasonic changes in workers exposed to perchloroethylene

OBJECTIVE

To determine if subclinical hepatotoxicity is associated with exposure to perchloroethylene at concentrations commonly experienced in the workplace, and whether surveillance with serum hepatic transaminase activity underestimates such effects.

METHODS

Hepatic parenchymal echogenicity on ultrasonography and serum hepatic transaminase activity were compared in 29 community based dry cleaning operators exposed to perchloroethylene, and a control group of 29 non-exposed laundry workers. Perchloroethylene exposure was assessed by work history and air monitoring.

RESULTS

Mean hepatic transaminase activities were minimally increased in dry cleaners compared with laundry workers. Increased alanine aminotransferase activities, between 1.0 and 1.5 times the normal limits, were found in five of 27 (19%) dry cleaners compared with one of 26 (4%) laundry workers. In contrast, diffuse parenchymal changes in echogenicity, as determined by hepatic ultrasonography, were increased nearly twofold in dry cleaners, occurring in 18 of 27 (67%) dry cleaners compared with 10 of 26 (39%) laundry workers (P < 0.05), and were most strongly associated with increased perchloroethylene exposure in older dry to dry or wet transfer operations (odds ratio 4.2, 95% confidence interval 1.1-15.3). Mean eight hour time weighted average perchloroethylene exposure for dry cleaners was 16 ppm, which is less than the permissible exposure limit of 100 ppm in the United States.

CONCLUSIONS

It was concluded that mild to moderate hepatic parenchymal changes occur more frequently in workers exposed to perchloroethylene than in populations not exposed to chemical solvents, and that these effects are underestimated by serum hepatic transaminase activity.

Workers' compensation for nonmalignant asbestos-related lung disease

Workers' compensation claims filed for occupational illness are generally more complicated to resolve than are injury claims, and they may therefore face higher likelihood of rejection. This study analyzed outcomes and predictive factors for claims filed from one clinic in Washington State between 1982 and 1986 by 157 male patients for nonmalignant asbestos-related lung disease. Among 50 federal Longshore claims, 46 (92%) were unresolved or could not be located by claims administrators. In contrast, 118 (89%) of State Fund claims had been resolved, with 48% accepted without consistent relationship to disease severity. Claims filed under both jurisdictions showed a twofold greater risk of rejection by the State Fund (relative risk, RR = 2.0; 95% confidence interval, 95% CI = 1.3-3.2). State Fund claims filed for nonwhite patients were rejected more often than those of white patients, although the association was explained at least partially by jurisdictional overlap (adjusted RR = 1.5; 95% CI = 1.05-2.1). This study indicates a need to scrutinize the handling of occupational disease claims by the federal Longshore system and to consider the adverse influences of jurisdictional conflicts and possible race-associated factors on compensation of occupational illness.

Multiple chemical sensitivity syndrome: a clinical perspective. I. Case definition, theories of pathogenesis, and research needs

Multiple chemical sensitivity syndrome (MCS) does not appear to fit established principles of toxicology. Yet social, political, and economic forces are demanding that MCS be defined medically, even though to date scientific studies have not identified pathogenic mechanisms for the condition or any objective diagnostic criteria. Consequently, a working definition of MCS can rely only on an individual's subjective symptoms of distress and attribution to environmental exposures rather than currently measurable objective evidence of disease. Nevertheless, patients labeled with MCS are clearly distressed and many are functionally disabled. In this review, four theories of causation are explored: (1) MCS is a purely biologic/physical or psychophysiologic reaction to low-level chemical exposures. (2) MCS symptoms may be elicited by low-level environmental chemical exposures, but the sensitivity is initiated by psychologic stress. (3) MCS is a misdiagnosis and chemical exposure is not the cause. The symptoms may be due to misdiagnosed physical or psychologic illness. (4) MCS is an illness belief system manifest by culturally shaped illness behavior. Areas for further research regarding the etiologies of MCS are suggested. Recognizing that the cause of the syndrome may be multifactorial, strategies are proposed for clinical evaluation and management in Part II of this manuscript using a biopsychosocial model of illness.

Multiple chemical sensitivity syndrome: a clinical perspective. II. Evaluation, diagnostic testing, treatment, and social considerations

Multiple chemical sensitivity syndrome (MCS) does not appear to fit established principles of toxicology. Social, political, and economic forces are demanding that MCS be defined medically, even though scientific studies have failed as yet to identify pathogenic mechanisms for the condition or any objective diagnostic criteria. Consequently, a working definition of MCS can only rely on a person's subjective symptoms of distress and attribution to environmental exposures rather than currently measurable objective evidence of disease. Nevertheless, patients labeled with MCS are clearly distressed and many are functionally disabled. Without reconciling the different theories of etiology of MCS discussed in Part I of this report, and recognizing that the cause of the syndrome may be multifactorial, strategies are proposed for clinical evaluation and management of patients with MCS using a biopsychosocial model of illness. The social implications of this illness are also discussed.

Solvents and color discrimination ability. Nonreplication of previous findings

Previous research has shown exposure-related increases in the prevalence of acquired color vision deficits among printers. We administered the Lanthony D-15 desaturated test of color vision to 82 print shop workers. Two tests of cognitive function, Trails A and B and the Symbol Digit Modalities Test, were also administered. Personal air sampling indicated that current exposure to organic solvents was highest among printers and lowest among bindery workers. In contrast to previous studies, the age-adjusted quantitative Lanthony D-15 desaturated test error scores did not differ significantly between exposure groups, and the proportion of subjects with > or = 1 error was greater in the lower-exposure, rather than higher-exposure, groups (P = .03). Of note, the proportion of subjects with > or = 2 errors did not differ significantly between groups (P = .24). Cognitive tests showed no significant association with exposure. These results are discussed in the context of methodological issues related to lighting sources, reliability of test results, and establishment of criteria for identifying deficits.

Immunologic, psychological, and neuropsychological factors in multiple chemical sensitivity. A controlled study

OBJECTIVE

To examine the role of immunologic, psychological, and neuropsychological factors in multiple chemical sensitivity.

DESIGN

Case-control comparison.

SETTING

Community allergy practice (cases), university-based clinics for musculoskeletal injuries (controls).

PARTICIPANTS

Forty-one patients with chemical sensitivity and 34 control patients with chronic musculoskeletal injuries.

MAIN OUTCOME MEASURES

Immunologic measures included autoantibody titers, lymphocyte surface markers, and interleukin-1 generation by monocytes. Psychological evaluation included standardized measures of anxiety, depression, and somatization.

RESULTS

Immunologic testing did not differentiate patients with chemical sensitivity from controls. The only difference noted (lower interleukin-1 generation among cases) appeared attributable to laboratory methods. Patients with chemical sensitivity reported greater prevalence of current anxiety or depressive disorder (44% versus 15%, P = 0.006). This difference, however, did not appear to precede the onset of chemical sensitivity, and 25% of chemically sensitive patients showed no significant current psychological disturbance. Cases reported significantly more "medically unexplained" physical symptoms before and after the onset of chemical sensitivity. When considering only symptoms that preceded chemical sensitivity, 25% of cases (and no controls) satisfied criteria for somatization disorder. Neuropsychological testing revealed no significant case-control differences.

CONCLUSIONS

Immunologic testing failed to confirm findings from earlier uncontrolled studies, militating against proposed immunologic mechanisms. The decreased memory and concentration frequently described in multiple chemical sensitivity were not confirmed by brief neuropsychological testing. Psychological symptoms, although not necessarily etiologic, are a central component of chemical sensitivity.

Neuropsychological performance and solvent exposure among car body repair shop workers

A cross sectional study to evaluate symptom reporting and neuropsychological test performance among a cohort of car body repair workers (n = 124) was performed using a computer-administered test system. Subjects with high and medium current exposures to solvent and paint (n = 39 and 32), and low exposure subjects who formerly painted (n = 29) reported significantly more acute and chronic neurological symptoms than did low exposure subjects with no history of painting (n = 24). Subjects with higher current exposure performed significantly less well on selected tests of visual perception and memory, but there were no significant exposure related differences in mood state, motor speed, or visuomotor performance. The exposure related effects were most noticeable among subjects 35 years or older. The findings are consistent with age interactive central neurotoxic effects of current exposure to solvents or of cumulative past exposure, although the study is unable to distinguish between these possibilities. The computer administered test system was effective in this field based investigation involving multiple, geographically dispersed worksites.

The 10-year experience of an academically affiliated occupational and environmental medicine clinic

Occupational and environmental diseases are underrecognized. Among the barriers to the successful diagnosis, treatment, and prevention of these conditions are inadequate consultative and information resources. We describe the 10-year clinical and training experiences of an academically affiliated referral center that has as its primary goal the identification of work-related and other environmental diseases. The University of Washington Occupational and Environmental Medicine Program has evaluated 6,048 patients in its diagnostic and screening clinics. Among the 2,841 seen in the diagnostic clinics, 1,553 (55%) had a work-related condition. The most prevalent diagnoses included asbestos-related lung disease (n = 603), toxic encephalopathy (n = 160), asthma (n = 119), other specific respiratory conditions (n = 197), carpal tunnel syndrome (n = 86), and dermatitis (n = 82). The clinics serve as a training site for fellows in the specialty training program, primary care internal medicine residents, residents from other medical specialties, and students in industrial hygiene, toxicology, and occupational health nursing. The program serves two additional important functions: providing consultative services to community physicians and training specialists and other physicians in this underserved area of medicine.

The contributions to solvent uptake by skin and inhalation exposure

Solvent exposures were assessed among 97 auto body repair workers in order to determine whether skin contact represented a significant route of exposure. Each subject's cumulative skin exposure was ranked categorically based on simple observation: 49 none, 33 incidental or low, and 15 moderate or high. The median time-weighted average air exposure to solvents was 8.4% of the American Conference of Governmental Industrial Hygienists (ACGIH) combined solvent threshold limit value (TLV) with a range of 0-62% TLV, including toluene (median 4 ppm) and xylenes (median 0.9 ppm). Urine methyl hippuric acids (MHAs, metabolites of xylenes) were low compared to the ACGIH biological exposure index (BEI) with a median of 2% and a range of 0-12% BEI but were strongly correlated with both the level of airborne xylenes and skin exposure when considered simultaneously by using analysis of covariance (R = 0.91, p less than 0.0001). MHA excretion attributable to skin exposure for 15 min or more generally was comparable to or greater than that from associated air exposure over the full work shift. This study had limited ability to assess quantitatively the contributions of toluene exposures, but there was evidence that skin exposures also contributed significantly to toluene absorption. Air sampling will substantially underestimate a worker's total solvent dose in the setting of moderate or high skin exposure. Simple observation was effective in identifying workers in this sample who appeared to have sufficient skin exposure to produce a measurable increase in solvent uptake.

Trial of a negative ion generator device in remediating problems related to indoor air quality

It has been suggested that supplementation of indoor air with negative ions can improve air quality. This study examined the effects of a "negative ion-generator" device on air contaminants and symptom reporting in two office buildings. Separate sets of functional and nonfunctional negative ion generators were monitored using a double blind, crossover design involving two 5-week exposure periods. There were no detectable direct or residual effects of negative ion generator use on air ion levels, airborn particulates, carbon dioxide levels, or symptom reporting. Symptom reporting declined at both sites initially and appeared to be consistent with placebo effect. Job dissatisfaction was an apparent contributor to symptom reporting, with a magnitude comparable to presumed effects of air quality. Further testing of such devices is needed before they should be considered for office air quality problems.

Chronic neuropsychological sequelae of occupational exposure to organophosphate insecticides

The early (immediate and delayed) neurotoxic effects of acute organophosphate intoxication are well documented in the scientific literature; lack of recognition and inappropriate treatment of occupational poisonings continue. Less well understood is the potential development of chronic neuropsychological sequelae from exposures to insecticides. We undertook two cohort studies to assess chronic neuropsychologic effects of insecticide poisoning. Based, in part, on our clinical evaluation of several patients, these studies included: 1) a retrospective cohort study assessing function at least 1 year following moderate to severe poisonings among farm workers; and 2) a prospective cohort study assessing neuropsychological function before and after a season of organophosphate exposures among pesticide applicators. A typical case description, the study design, methodologic problems, and preliminary findings of these ongoing studies are presented.

Firefighting acutely increases airway responsiveness

The acute effects of the products of combustion and pyrolysis on airway responsiveness among firefighters are poorly documented. To study this relationship, spirometry and methacholine challenge testing (MCT) were performed on 18 active Seattle firefighters before and 5 to 24 h after firefighting. Body plethysmography was used to measure changes in specific airway conductance (SGaw), and results of MCT were analyzed using PD35-SGaw, the cumulative dose causing a 35% decrease in SGaw. Subjects who did not react by the end of the protocol were assigned a value of 640 inhalational units, the largest cumulative dose. Fire exposure was defined as the total time (hours) spent without a self-contained breathing apparatus at the firesite and was categorized as mild (less than 1 h, n = 7), moderate (1 to 2 h, n = 5), or severe (greater than 2 h, n = 6). Mean age of the 18 firefighters was 36.7 +/- 6.7 yr (range, 25 to 51), with a mean of 9.1 +/- 7.9 active years in the trade (range, zero to 22). None was known to be asthmatic. After firefighting, FEV1 % predicted (%pred) and FEF25-75 %pred significantly decreased by means of 3.4 +/- 1.1% and 5.6 +/- 2.6%, respectively. The mean decline in PD35-SGaw after firefighting was 184.5 +/- 53.2 units (p = 0.003). This observed decline in PD35-SGaw could not be explained by decrements in prechallenge SGaw, FEV1, or FVC.(ABSTRACT TRUNCATED AT 250 WORDS)

Occupational medicine: carpal tunnel syndrome-a cumulative trauma disorder

The Scientific Board of the California Medical Association presents the following inventory of items of progress in occupational medicine. Each item, in the judgment of a panel of knowledgeable physicians, has recently become reasonably firmly established, both as to scientific fact and important clinical significance. The items are presented in simple epitome, and an authoritative reference, both to the item itself and to the subject as a whole, is generally given for those who may be unfamiliar with a particular item. The purpose is to assist busy practitioners, students, research workers, or scholars to stay abreast of these items of progress in occupational medicine that have recently achieved a substantial degree of authoritative acceptance, whether in their own field of special interest or another.The items of progress listed below were selected by the Advisory Panel to the Section on Occupational Medicine of the California Medical Association and the summaries were prepared under its direction.