Purpose

Most environmental and occupational diseases either manifest as common medical problems or have nonspecific symptoms. Unfortunately, hazardous exposures rarely enter into the clinician's differential diagnosis. As a result, clinicians may miss the opportunity to make correct diagnoses that might influence the course of disease. A correct diagnosis may help stop exposure and might prevent disease in others by avoiding exposure [Gehle et al. 2011; Goldman and Peters 1981].

What can a clinician do to improve recognition of disease related to current or past exposures?

• First, one must be suspicious and think about the possibility of environmental and occupational factors of disease.
• Next, one needs to incorporate an exposure history questionnaire into clinical practice.

This course illustrates the principles and practices involved in the development of a differential diagnosis that includes possible hazardous exposure related etiologies.

Benefits

Taking an exposure history may enable physicians to

• Make more accurate diagnoses,
• Influence the course of disease by stopping current exposure,
• Prevent disease in others by avoiding future exposure, and
• Prompt workplace evaluations and the protection of workers.

Goals

The goals of taking an exposure history are

• Identifying the hazard,
• Avoiding or stopping the exposure,
• Preventing disease,
• Identifying and treating disease early, and
• Arresting or reversing the progression of the patient's illness.

Exposure Factors and Etiology

The preceding case study describes a patient with angina. He has new, nonspecific symptoms of headache and nausea.

Suppose this patient lived near a hazardous waste site.

• Would your differential diagnosis change?
• If the patient refinished furniture as a hobby, would you consider this important?
• Is there a connection between his headaches and cardiac symptoms?
• How would you investigate the possible correlation?
• Could he be exposed to chemicals in his workplace?

Each of these factors could play a role in the etiology of this patient's illness; each exposure could cause disease.

Three Scenarios

The patient described in the case study - a 52-year-old male with angina - is portrayed in three scenarios throughout this document. An exposure history provides clues that prompt the clinician to investigate the possibility of toxic exposure.

• Scenario 1: This patient is an accountant who has had the same job and the same residence for many years.
• Scenario 2: This patient owns a commercial cleaning service and uses cleaning products at various industrial and commercial sites.
• Scenario 3: This patient is a retired advertising copywriter who lives in the vicinity of an abandoned industrial complex.

In each scenario, the clinician's pursuance of the exposure history led to discovery of toxic exposure in each of the three cases.

In each case, the diagnosis and treatment might have been inappropriate without an exposure history.

Etiology Denotes Environmental and Occupational Diseases

Most environmental and occupational diseases either manifest as common medical problems (e.g., rashes, asthma, angina, spontaneous abortion) or have nonspecific symptoms (e.g., headache, difficulty concentrating, behavioral problems, myalgias, difficulty conceiving) [Amdur MO 1991; Marshall et al. 2002; Wigle D 2000].

Establishing the etiology can distinguish a disorder as an environmental illness.

Unless an exposure history is pursued by the clinician, the etiologic diagnosis might be missed, treatment may be inappropriate, and exposure can continue.

Progress Check