Past and current exposures are recorded on Part 1 of an Exposure History Form, which is designed for easy completion by the patient and a quick scan for pertinent details by the clinician.

The questions investigate

• changes in routines and work site characteristics
• details about known toxicant exposure
• known exposure to metals, dust, fibers, fumes, chemicals, physical agents, and biologic hazards
• other persons affected
• protective equipment use
• temporal patterns and activities

If the patient answers yes to one or more questions on Part 1, the clinician must follow up by asking the patient progressively more detailed questions about the possible exposure. Special attention should be directed to the route, dose, duration, and frequency of any identified exposure.

Scenario 1

• 52-year-old male accountant with angina
• chief complaints: headache and nausea

The chart of the patient described in Scenario 1 of the case study reveals that he has worked as an accountant in the same office for the past 12 years. On Part 1 of the completed Exposure History Form, he indicates that no other workers are experiencing similar or unusual symptoms, and he denies recent changes in his job routine.

The patient answered yes to these three questions: “Are family members experiencing the same or unusual symptoms?” “Do your symptoms get either worse or better at work?” and “Do your symptoms get either worse or better on weekends?” His explanations of these answers reveal a possible temporal relationship between his symptoms and his home.

The clue and the clinician/patient dialogue follow.

Clinician: I see that you noted that your wife is having headaches.

Patient: Yes; frequently. In the last three or four weeks she has had more than usual. She usually has one every month or so; this past month she had three.

Clinician: You also stated that your headaches are worse on weekends.

Patient: Yes, they seem to be. If I wake up on a Saturday or Sunday with a headache, it usually gets worse as the day progresses. In fact, that's usually when I feel nauseated too.

Clinician: Do your symptoms seem to be aggravated by certain activities around the home? A hobby or task?

Patient: No, I usually wake up with the headache. I don't think there's a connection with anything I do.

Clinician: Do your symptoms change at all at work?

Patient: Now that you mention it, if I wake up with a headache, by the time I get to work—it takes about 25 minutes—the headache is usually gone.

Clinician: Your angina attack occurred on a Sunday morning. Describe your weekend leading up to the attack.

Patient: It was a fairly quiet weekend. We had dinner at home Friday evening and just relaxed. On Saturday I spent the day packing old books and storing them in the attic and chopping and stacking firewood. I took one nitroglycerin tablet before doing the heavy work, at about 2:00 PM. Saturday night we had friends over for dinner. We had a fire in the fireplace and visited until about 11:00 PM. I had one glass of wine with dinner. I was beginning to feel a little stiff and sore from the work I did that afternoon. Sunday morning I woke up with a headache again. A few minutes after awakening, while I was still in bed, I had the attack. It was mild, not the crushing pain I've had in the past. I had the headache all day.

The preceding dialogue reveals that the patient's symptoms may be associated with the home environment, and his cardiac symptoms, headache, and nausea may be related.

His symptoms seem to be exacerbated at home and lessen at work. Further questioning is needed to pursue this lead.

Clinician: What does your wife do for a living?

Patient: She's an attorney.

Clinician: Do either of you have a hobby?

Patient: My hobby is photography. My wife is an avid gardener.

Clinician: Do you have your own darkroom?

Patient: No, I occasionally use a friend's darkroom, but for the past year I've had my film and prints processed commercially.

Clinician: Does your wife use any pesticides or chemicals in the garden?

Patient: No, she does strictly organic gardening and uses only natural means of pest control.

Clinician: Do you work on your car?

Patient: No.

Clinician: Have you gotten any new furniture or remodeled your home in the past few years?

Patient: No.

Clinician: What is your source of heating and cooking in the home?

Patient: We have a natural gas, forced-air heating system. We cook with gas and use the fireplace a lot in winter.

Clinician: How long have you lived in this home and how old is your furnace?

Patient: We've lived there for 23 years. The furnace was replaced about 12 years ago.

Clinician: I see that you recently insulated your home. What exactly did you do?

Patient: Yes. Last month I added extra insulation to the attic, insulated the crawl space, replaced all the windows with double-paned windows, and weatherized all doorways.

Clinician: Have you noticed that the headaches coincide with days you have used the fireplace?

Patient: There could be a connection. I definitely use the fireplace more on weekends. This past Saturday I had a fire blazing all day.

A temporal relationship between the headaches and being in the home has been revealed. Some sources of toxicants have been eliminated (formaldehyde and other volatile organic chemicals from new furniture and rugs and toxic chemicals used in hobbies or gardening).

There may be a correlation between symptoms and use of the fireplace. The fireplace could increase negative pressure in the house, causing back drafting of furnace gases. The furnace is old; it may be malfunctioning or producing excessive carbon monoxide. The patient's symptoms, including his angina attack, would be consistent with carbon monoxide poisoning.

Although the patient's symptoms could be associated with his preexisting disease, evidence is strong enough at this point to investigate the possibility of environmental exposure.

It would be appropriate to contact the local gas company to request that it check the furnace and stove for malfunctions and leaks. The fireplace should be checked for proper drafting and for deposits of creosote in the chimney.

A carboxyhemoglobin (COHb) level on the patient may confirm carbon monoxide poisoning. The patient should be advised to ventilate the house until the furnace is checked or to stay out of the house until the gas company deems it safe.

COHb levels are important in diagnosis of carbon monoxide exposure. In nonsmoking patients, a COHb level greater than 5% confirms exposure. (Tomaszewski 1999) A COHb level performed on this patient is 6%, which is high for a nonsmoker. The gas company discovers a cracked heating element in the 12-year-old furnace, which resulted in the circulation of carbon monoxide throughout the house. The use of the fireplace most likely increased the back drafting of fumes. The furnace is replaced, the exposure ceases, and the patient's symptoms abate. He experiences no further cardiac symptoms.

The exposure history form may also alert the clinician to past exposures.

Most often, neither the job title nor the patient's initial description of job duties reveal clues of exposure. It is usually helpful to have a patient describe a routine work day, as well as unusual or overtime tasks. Patients tend to use jargon when describing their jobs. It is the clinician's challenge to persistently question the patient to elucidate possible exposures; it is not necessary to have foreknowledge of a particular trade. Start with general questions and work toward the more specific.

Part 1 of the form reveals another clue—this patient was exposed to asbestos about 30 years ago. The questioning that the clinician conducts, despite having neither knowledge of the patient's trade nor understanding of the jargon, follows.

Clinician: You state here that you were exposed to asbestos, fiberglass, and welding fumes way back in 1976.

Patient: Yes, during my days as a shipwright.

Clinician: Did you actually handle the asbestos?

Patient: No, the pipe laggers were the tradesmen that handled the asbestos.

Oh, you might be setting a bracket or plate next to a pipe and accidentally hit the pipe and dislodge some asbestos, but otherwise, shipwrights didn't handle it. You only had asbestos where there were steam lines from the boiler carrying high-pressure steam to other units like a winch or an auxiliary motor.

Clinician: What does a shipwright do? What was a routine day for you?

Patient: There was no routine day. The shipwrights were the cream of the journeymen crop; we did everything from outfitting, to establishing the cribbing on the launching gang, to shoring. I worked on the outfitting docks.

We did ship reconversion. I did a lot of work on the forepeak and hawse pipes when I wasn't working below deck.

Clinician: What exactly were your tasks below deck?

Patient: Most transporters were converted to passenger ships after the war; there was a lot of shifting of equipment and pipes. Basically, the ships were gutted. They would be completely revamped. The shipwrights would do all the woodworking, finish work, plates, and so on. Then, when everything was in place, it would be insulated, and the pipes would be lagged.

Clinician: So you worked throughout the ship? And when you finished your tasks, the laggers would come in?

Patient: No, no. There might be 10 different tradesmen working in an afterpeak at one time. You'd be working next to welders, flangers, pipe fitters, riveters, laggers; you name it. These conversions were done round-the-clock, seven days a week; it could take a year and a half to complete a conversion. All the tasks were being done simultaneously.

Clinician: How long would the lagging take?

Patient: The lagging could take six to 10 months, sometimes longer. They were constantly cutting these sections of asbestos to fit the pipes. Then they would attach the sections with a paste and wrap it with asbestos wrapping.

Clinician: Could you see the asbestos in the air?

Patient: Oh yes. Sometimes it was so thick you couldn't see five feet in front of you. It was white and hung in the welding fumes like smog.

Clinician: Did you use any protective equipment? Masks? Respirators?

Patient: No. Nobody ever said it was dangerous. We were bothered more by the fiberglass and welding fumes than anything. We thought fiberglass was more dangerous because it was itchy and caused a rash. The air was blue from the welding fumes; if you worked in that for a year, you knew it was affecting you. It inspired me to go back to school and get my accounting degree. But we were blue-collar workers; we were more concerned with welders' flash, a boom breaking, or someone getting crushed between plates than we were with asbestos.

Clinician: You worked as a shipwright for six years?

Patient: Yes, about that. Five of those years as an outfitter on conversions.

The dialogue in which the clinician engaged the patient neither determines whether the patient's asbestos exposure was significant, nor does it confirm that he suffered adverse effects from the exposure. It is merely a starting point for investigation.

The questioning establishes that approximately 30 years ago this patient received a possibly severe exposure to asbestos fibers for a duration of five or six years. Because quantitative data on this patient's exposure are impossible to obtain, a qualitative description (“Sometimes it was so thick you couldn't see five feet in front of you”) can facilitate assessment of the exposure when consulting with an occupational medical specialist.

In this scenario, the disclosure should prompt the clinician to monitor the patient closely for early detection of treatable health effects from asbestos exposure. A chest radiograph would be advised and pulmonary function tests should be considered. Vaccination for influenza may be warranted, depending on the results of the chest radiograph. Consulting an occupational medical specialist could help determine the best way to evaluate and treat this patient.

In this scenario, the clinician successfully diagnosed an illness due to an environmental toxic exposure (carbon monoxide) and noted a significant past exposure (asbestos) that needs follow-up.

Had the clinician failed to pursue an exposure history, the patient's current illness might have been misdiagnosed, treatment might have been inappropriate, or measures might not have been implemented to prevent further carbon monoxide exposure, leading to a risk of continued progression of the angina as well as the possibility of harmful health effects for patients and other residents of the household for carbon monoxide poisoning.

Progress Check