CHAPTER 4-2: EVALUATION OF THE PATIENT WITH OCCUPATIONAL CHEMICAL EXPOSURE

INTRODUCTION

This chapter highlights common toxicologic problems in the workplace. Occupationally related disease is encountered commonly in the outpatient setting. Estimates of the proportion of occupationally related medical problems in primary care practices range up to 15–20%, although this includes many patients with musculoskeletal complaints. However, approximately 5% of all symptomatic poison control center consultations are occupational in nature, suggesting a large number of work-related chemical exposures do occur.

1. General considerations

   1. Occupational illness is rarely pathognomonic. The connection between illness and workplace factors is typically obscure unless a specific effort is made to link exposure to disease.

      1. Massive or catastrophic events leading to the acute onset of symptoms, such as release of an irritant gas, are relatively uncommon but easily recognized.

      2. For most workplace exposures, symptom onset is more often insidious, following a subacute or chronic pattern, as in heavy metal (e.g., lead) poisoning.

      3. Long latency, often years between exposure and disease, makes linking cause and effect even more difficult—for example, in chronic lung disease or occupationally related cancer.

   2. Occupational evaluation frequently includes legal and administrative components.

      1. Occupational illness, even if suspected but not established, may be a reportable illness in certain states (eg, in California through its Doctor's First Report system).

      2. Establishing quantifiable documentation of adverse effects at the time of exposure may be critical to future attribution of impairment (eg, spirometric evaluation soon after an irritant inhalant exposure).

      3. Although workers' compensation is in theory a straightforward "no-fault" insurance system, in practice it often is arcane and adversarial. It is important to remember that the person being treated is the patient, not the employer or a referring attorney.

2. Components of the occupational exposure history

   1. Job and job process

      1. Ask specifics about the job. Do not rely on descriptions limited to a general occupation or trade, such as "machinist," "painter," "electronics worker," or "farmer."

      2. Describe the industrial process and equipment used on the job. If power equipment is used, ascertain how it is powered to assess carbon monoxide exposure risk.

      3. Determine whether the work process uses a closed system (eg, a sealed reaction vat) or an open system. Ascertain what other processes or workstations are nearby. Work under a laboratory hood may be an effectively "closed" system, but not if the window is raised too far or if the airflow is not appropriately calibrated.

      4. Find out who does maintenance and how often it is done.

   2. Level of exposure

      1. Ask whether dust, fumes, or mist can be seen in the air at the work site (even an outdoor work environment). If so, question whether coworkers or nearby objects can be seen clearly (very high levels actually obscure sight). A history of dust-laden sputum or nasal discharge at the end of the work shift is also a marker of heavy exposure.

      2. Ask whether work surfaces are dusty or damp and whether the paint at the work site is peeling or discolored (eg, from a corrosive atmosphere).

      3. Determine whether strong smells or ...