Introduction

Environmental and occupational factors contribute to more than 25% of all global disease [Smith et al. 1999; WHO 2007], and toxic agents ranked fifth in underlying causes of U.S. deaths in 2000 [Mokdad et al. 2004].

Many people with illness caused or exacerbated by exposure to hazardous substances obtain their medical care from clinicians who are not specialists in environmental or occupational medicine.

Consideration of environmental and occupational exposures rarely enters into the clinician's history taking or diagnosis [Marshall et al. 2002]. Environmental medicine education is largely omitted in the continuum of U.S. medical education, leaving future physicians and current practitioners without expertise in environmental medicine to provide or facilitate environmental preventive or curative patient care [Gehle et al. 2011].

What Happens in the Clinical Setting

A chart review of 2,922 histories taken by 137 third-year medical students showed that smoking status was documented in 91%, occupation in 70%, and specific occupational exposures in 8.4% of the total number of cases. Patients less than 40 years of age and women were significantly less likely than older patients or men to have their occupation and industry noted [Marshall et al. 2002; McCurdy et al. 1998].

Findings from another study showed that work-related issues might not be adequately addressed or documented in the provider's clinical notes and that opportunities for preventive care relating to work-related injuries and illnesses may not be realized in the primary care setting [Thompson et al. 2000].

A recent report about U.S. medical schools disclosed that graduating students received inadequate instruction in environmental health [AAMC 2010].

A recent national online survey of American Congress of Obstetricians and Gynecologists (ACOG) fellows showed that among 2,514 survey responses, 50% reported that they rarely take an environmental health history; less than 20% reported routinely asking about environmental exposures commonly found in pregnant women in the United States; and only 1 in 15 reported any training on the topic [Stotland et al. 2014].

Practicing primary care physicians report the need for environmental medicine education to better recognize, diagnose, and treat patients in their clinical practice with environmental related illness [Gehle et al. 2011].

What Clinicians Need to Do

The single most important aspect of the approach to patients with potential occupational or environmental disease is to have a high index of suspicion and to follow through on that suspicion [Frank AL 2000]. Although many clinicians recognize the importance of taking a work and exposure history to evaluate certain problems, most have had little training or practice in doing so [Becker 1982; Frank AL 2000; Gehle et al. 2011; Kilpatrick et al. 2002; Merritt 1999; Pope AM and Rall DP 1995; Stotland et al. 2014].

There are numerous resources available to practitioners who may want to spend the time and effort needed to better understand environmental and occupational issues.

Extensive knowledge of toxicology is not needed to diagnose environmental and occupational disease. The criteria employed are the same as those used for diagnosing other medical problems:

• History, including onset and temporal pattern of symptoms, noting palliative and provocative factors;
• Physical examination; and
• Laboratory results.

If necessary, consultation with other health professionals such as industrial hygienists or occupational health nurses may facilitate the gathering of useful information concerning exposures. See the "What Are Additional Environmental Health Resources" section for additional information.

Industrial hygienists, who are often employed by state health departments or industry, are a source of information to the clinician investigating a possible toxic exposure. Industrial hygiene is the discipline devoted to the recognition, evaluation, and control of workplace-related factors or stresses that may cause illness, impaired health or well-being, or significant discomfort and inefficiency among workers or community members. They can be helpful in assessing whether a significant exposure has occurred.

Occupational health nurses, who often work at patients' work sites, also have expertise and experience that may be valuable to the clinician.

Medical specialists, such as board certified clinicians specializing in occupational and environmental medicine or medical toxicology can assist the primary health care provider in the evaluation and management of patients exposed or potentially exposed to hazardous substances.

For more information on clinical consultation resources, please see the section "What Are Additional Environmental Health Resources?"

In addition to current exposures, the clinician must consider the long-term or latent effects of past exposures to agents such as asbestos, radiation, and chemical carcinogens.

Taking an exposure history creates the opportunity to counsel patients in appropriate preventive behaviors to mitigate or limit their exposure risk.

Exposure History Form

The exposure history form (see Appendix I) can be completed by the clinician, other office staff, or by the patient. This information will help guide the clinician through various aspects of the process. This form elicits many important points of an exposure history, including job descriptions and categories associated with hazardous substances, or physical and biologic agents. In addition, it may suggest temporal and activity patterns related to environmental and occupational disease.

The form explores past and current exposures and comes in several formats including an editable electronic version (see Appendix I for more information on available formats).

Process Takes Just a Few Minutes

Taking an exposure history requires only a few minutes and can be

• Abbreviated,
• Expanded, or
• Focused according to the patient's signs and symptoms.

The exposure history form is designed for quick scanning of important details. Its contents can be added to the electronic health record as baseline information that may aid in the investigation of current or future problems.

An exposure history should be taken on every patient. It is of particular importance if the patient's illness occurs at an atypical age or is unresponsive to treatment.

Use Sound Judgment

The diagnosis of environmental and occupational disease cannot always be made with certainty. Sound clinical judgment must be used and common etiologies should be considered. The multi-factorial nature of many conditions, particularly chronic diseases, should not be overlooked.

The clinician must also keep in mind that many organ systems are affected by toxic exposures (Table 2). Exposure and effects can be acute or chronic. The latency period from exposure to disease manifestation can vary, ranging from immediate to delayed (hours or days) or prolonged (decades).

Conclusion

With practice using the exposure history form and utilizing appropriate clinical resources when necessary, the primary care clinician can play an important role in the detection, treatment, and prevention of diseases that may result from toxic exposures.

Progress Check