Selected topics related to occupational exposures.

The auditory and nonauditory effects of noise can be quite profound, affecting approximately 15 to 20 million Americans. As with most occupational toxins, recognition and careful assessment of noise exposure are the foundation on which preventive measures and treatment are based. Dosimeters can measure noise exposure over specific time periods. Pure tone air conduction audiometric monitoring should be performed on an annual basis in workers at risk for significant noise exposure. Occupational infectious disease involves far more than hepatitis and tuberculosis. Periodic fever, dermatologic manifestations and other symptoms peculiar to a specific disease may be important clues to an occupationally related exposure. Whereas strict attention to hand washing and isolation are cornerstones of prevention, use of protective gear is mandated in certain situations. Zoonotic disease, agriculture exposure, water transmission, and biologic contaminants in buildings can be important but subtle exposures sources. Recognition of these infections often depends on the alertness of the primary care giver.

Selected topics related to occupational exposures. Part III. Occupational dermatology

Occupational skin disorders are very common and are a surprisingly frequent cause of lost work time. Failure to suspect an occupational cause can lead to repeated treatment failure and needlessly prolong patient misery and frustration. Primary care providers play a key role in recognizing possible occupational causes and arranging appropriate education, preventive measures, and treatment. Occupational skin conditions often occur in nonindustrial settings in workers such as hairdressers, health care personnel, and food handlers. Irritant contact dermatitis is by far the most prevalent occupational skin condition and is emphasized in this article. Allergic contact dermatitis, infections, skin cancers, and acneform eruptions may also have significant occupational associations. We will present criteria that suggest on occupational exposure, list common offending agents, and review the clinical presentations and relevant pathophysiology. We provide guidance on a directed history and physical examination and suggest when diagnostic testing is most likely to have value. Finally we outline preventive measures such as contact avoidance, barrier creams, and protective gloves and address therapy and indications for referral.

Selected topics related to occupational exposures. Part IV. Occupational liver disease

Occupational and environmental substances associated with liver injury include industrial chemicals, drugs, certain bacterial and viral infections, and other physical agents. Hepatotoxic chemical agents can be classified as direct hepatotoxins, indirect hepatotoxins, or agents that cause liver injury as a result of host idiosyncrasy. More than 100 industrial chemicals have been shown to be acutely hepatotoxic. Occupations with hepatotoxin exposures are numerous and include farm workers, chemists, dry cleaners, electroplaters, garage workers, health care workers, nurses, painters, printers, rayon makers, and others. Clinical presentation of occupational liver disease may be acute/subacute or chronic but is often insidious. Some hepatotoxins are capable of causing malignancy. The key to diagnosis of occupational liver disease is exposure history. The occupational and environmental history should include a brief description of the patient's current and recent jobs to the extent necessary to assess their potential for workplace hepatotoxic exposures. Confounders such as obesity, alcohol, and viral hepatitis are common, and a careful history and examination are essential. A variety of tests are used to evaluate liver disease and may include serum markers, tests of synthetic liver function, clearance tests, and anatomic tests. A key responsibility of the primary care provider is to prevent further liver injury from preventable occupational exposures; not only the patient but also coworkers may be at risk. Efforts should be made to ensure that patients with potential hepatotoxic exposures are working or living in safe conditions. Collaboration with an occupational specialist may be especially useful in this regard.

Selected topics related to occupational exposures. Part V. Occupational cardiovascular disease

Cardiovascular disease is common in the United States. Several occupational exposures, such as carbon disulfide and organic nitrates, are believed to cause occupational cardiovascular disease. In addition some other agents, such as lead and cadmium, may indirectly cause cardiovascular disease through their effects on blood pressure. For other agents (ie, carbon monoxide, solvents, and chlorofluorocarbons), acute exposure and high levels may cause cardiovascular disease but may not cause cardiovascular disease through long-term or low levels. A primary care physician who has a patient with a new or unstable cardiovascular disease should obtain an occupational history to assess whether occupational exposures may be playing a role. An occupational history may indicate potential cardiovascular risks. Such risks can include exposure to certain chemicals and metals, physical factors, exertion, or psychological stress. The primary care physician should be able to assess the situation and advise the patient, as well as the employer, about restrictions or accommodations that may need to be made.

Ambient noise levels in mobile audiometric testing facilities: compliance with industry standards.

Excessive ambient noise levels in audiometric test booths may elevate and therefore invalidate hearing thresholds of employees included in a hearing conservation program. This study was conducted to determine if a sample of mobile test vans and trailers operating in the Midwest met the 1983 Occupational Safety and Health Administration (OSHA) maximum permissible ambient noise levels (MPANLs), the MPANLs in the American National Standards Institute (ANSI) S3.1-1991, and the suggested National Hearing Conservation Association (NHCA) values. Ambient noise levels were measured in 13 audiometric test booths contained in 12 different industrial mobile test vans and trailers operating in the Midwest. Results indicated that all 13 (100%) of the industrial mobile test vans and trailers evaluated complied with 1983 OSHA permissible levels and the NHCA 1996 recommended levels. With regard to the 1991 ANSI MPANLs, 5 (38%) of the 13 booths were in compliance at all frequencies. Those that failed did so at 125, 250, and 500 Hz. It appears that the NHCA levels need to be used for all hearing conservation programs with respect to compliance for noise levels in mobile audiometric test booths.

Relative ear protector performance in high vs low sound levels.

The attenuation of one specific ear protector was determined for a group of five normal hearing subjects and a group of five hearing impaired subjects. The hearing impaired group yielded significantly less attentuation than the normal hearing group. Since the measuring sound intensity level was high for the hearing impaired listeners and low for the normal listeners, it appears that a threshold procedure using normal subjects, as presented in the American standard (ANSI S3.19-1974), may overestimate the actual attenuation of ear protectors in most noisy environments.