Case

A 66-year-old retired male presents with dyspnea on exertion. He first noticed the shortness of breath several months ago but was not concerned because it seemed so minor; he attributed it to aging. During the past few months, however, the dyspnea on exertion has gradually worsened.The patient has no other symptoms of respiratory or cardiac disease. His medical history is unremarkable except for

• An old back injury (compression fracture of L4) sustained while working as an electrician at a local shipbuilding facility and
• A 25 pack-year history of smoking, though the patient quit smoking 5 years ago.

On physical examination, the patient is in no apparent distress. Auscultation reveals bibasilar end-inspiratory rales. There are no signs of cyanosis, no clubbing of the fingers, and no peripheral edema. Heart sounds are normal, as are the results of the rest of the physical examination.

Questions

1. What further workup is required for this patient?

2. The exposure history indicates a 15-year history of exposure to asbestos at the shipyard, beginning 35 years ago and ending 20 years ago. The patient does not know the exposure levels but notes that he used a respirator during the last 5 years at the shipyard. In addition, when he was 21 years old, he swept floors at a vermiculite handling facility for a summer. He notes that the vermiculite plant was extremely dusty, but he was told it was just "nuisance dust."

   Are the patient's symptoms likely to be related to asbestos exposure? Why or why not?

3. On a conventional chest radiograph, the radiologist (a certified "B Reader") finds small, irregular opacities in both lung bases consistent with early-stage asbestosis. The pulmonary function tests reveal a mostly restrictive pattern of deficits, with decreased carbon monoxide diffusing capacity (DLco). You refer the patient to a pulmonologist. The pulmonologist diagnoses asbestosis on the basis of the patient's exposure history, latency of symptoms (occurring 45 years after first exposure), chest radiograph findings, and pulmonary function results.

   How will you manage the patient's condition?

4. Is the patient at risk for other asbestos-associated diseases? Why or why not?
5. Are the patient's family members at risk for asbestos-associated disease as a result of their association with the patient and his work with asbestos?

6. The patient has been married for 46 years and has four children. He notes that his wife laundered all his clothes from work, including his clothes from the summer job at the vermiculite plant and those from his job at the shipbuilding facility. His children had only incidental exposure from hugging him after work. The patient's wife, a two-pack-a-day smoker, has recently lost weight and developed sharp pains in her lower chest.

   Could the wife's recent weight loss and chest pain be related to her husband's occupational exposure to asbestos? What work-up would you suggest for the patient's wife?

7. The patient asks if his children are at risk of asbestos-associated disease. How do you answer?

Initial Check Answers

1. The exertional dyspnea and bibasilar end-inspiratory rales are suggestive of some type of interstitial pneumonitis. Because of the patient's history of work at a shipbuilding facility, a detailed exposure history is warranted. You should ask the patient about

   • Possible exposures (especially to asbestos) at the shipbuilding facility.
   • Other jobs at which the patient may have been exposed directly or indirectly to asbestos.
   • The source, intensity, frequency, and duration of any exposures.
   • The time elapsed since first exposure.
   • Any workplace dust measurements or cumulative fiber exposure.
   • Use of personal protective equipment.
   • Other sources of exposure, including paraoccupational exposures to or from members of the patient's household.
   • Sources of environmental exposure, such as a residence near exposed asbestos-bearing rock or hobbies or recreational activities that involve materials contaminated with asbestos (e.g., home repairs or auto maintenance).

   In addition to taking a detailed exposure history, it is prudent to order a chest radiograph and pulmonary function tests.

   The information for this answer comes from the "How Should Patients Exposed to Asbestos Be Evaluated?" section.

2. Yes, the patient's condition is likely to be related to asbestos exposure. Diagnoses to consider include

   • Asbestosis,
   • Idiopathic pulmonary fibrosis,
   • Other pneumoconiosis,
   • Hypersensitivity pneumonitis, and
   • Sarcoidosis and other interstitial pulmonary diseases.

   Several aspects of the patient's case point to asbestosis as a likely diagnosis.

   • History of exposure to asbestos in the shipbuilding facility and Libby vermiculite handling plant.
   • Onset of symptoms many years after the exposures (consistent with a long latency period).
   • Insidious onset of dyspnea on exertion.
   • Bibasilar end-inspiratory rales.

   The results of the chest radiograph (which should be read by a certified "B Reader") and pulmonary function tests will help with the differential diagnosis.

   The information for this answer comes from the "How Should Patients Exposed to Asbestos Be Evaluated?" section.

3. To manage this patient's condition, you will

   • Advise the patient to avoid any further exposure to asbestos, tobacco smoke, and other respiratory irritants as practical;
   • Provide pneumococcal and annual influenza vaccines;
   • Advise the patient to contact you at any sign of chest infection;
   • Aggressively treat any chest infections that develop in the patient;
   • Advise the patient to contact you at any sign of other health changes, particularly changes that might be early signs of a malignancy (e.g., hoarseness, change in cough, coughing up blood, sores in the mouth, blood in stool);
   • Arrange for colon cancer screening in accordance with current guidelines;
   • Schedule regular follow-up visits to monitor progression of the asbestosis and possible development of other asbestos-associated diseases;
   • Document any impairments related to work-related asbestos exposure; and
   • Notify the patient that he has an occupational disease and arrange for appropriate follow-up. Refer the patient to an occupational specialist who can explain all the treatment, legal (such as workman compensation) and employment ramifications of a work-related pulmonary disease.

   The information for this answer comes from the "How Should Patients Exposed to Asbestos Be Treated and Managed?" section.

4. Yes, the patient is at risk of other asbestos-associated diseases. The patient's past exposures to asbestos were significant enough to have led to the development of asbestosis. These exposures can also lead to the development of other asbestos-associated diseases such as asbestos-related pleural abnormalities, lung carcinoma, and pleural or peritoneal mesothelioma. Additionally, the patient was previously a smoker and the effects of smoking and asbestos exposure are synergistic with respect to lung cancer (i.e., patients with a history of both smoking and asbestos exposure face a risk greater than what would be expected if the individual effects of each of these two risk factors were simply summed).

   The information for this answer comes from the "What Other Health Conditions Are Associated with Asbestos?" section.

5. Possibly. While taking the patient's exposure history, it is important to ask about possible paraoccupational as well as environmental exposures to members of the patient's household. These can include inhalation of asbestos fibers from

   • The worker's skin, hair, and clothing (depending on PPE and post work showering was not used),
   • Air and dust from nearby vermiculite- or asbestos-handling facilities, and
   • Air and dust from nearby mining operations or other blasting/disruption of asbestos-bearing rock.
   • Outdoor recreation in areas of exposed asbestos-bearing rock.

   You should also ask about other possible exposure sources such as

   • Materials used for hobbies and recreation.
   • Outdoor activities that could involve exposure to asbestos-bearing rock, particularly if the patient lives near a geologic source.
   • Vermiculite attic insulation contaminated with asbestos.

   All of these types of exposures could place family members and other household contacts at risk of asbestos-associated disease.

   The information for this answer comes from section the "Who Is At Risk of Exposure to Asbestos?" section.

6. Yes, the wife's symptoms could be related to her husband's occupational exposures to asbestos. Given that she laundered her husband's work clothes when he had two jobs involving asbestos, she could have received significant paraoccupational exposures to asbestos. To determine whether these exposures led to an asbestos-associated disease, you recommend that the patient's wife:

   • Come in for an office visit,
   • Have a chest radiograph, and
   • Undergo pulmonary function tests.

   The wife's chest radiograph shows a pleural thickening associated with a slight pleural effusion on the lower right lung field. You refer the wife to a pulmonologist, who orders a computed tomography (CT) scan and performs a pleural biopsy. The pulmonologist diagnoses pleural mesothelioma, refers her to a cancer center, and provides the family with a referral for psychosocial support.

   The information for this answer comes from section the "How Should Patients Exposed to Asbestos Be Evaluated?" section.

7. You explain that the risk of asbestos-associated diseases is generally related to dose (duration multiplied by the level of exposure, or cumulative exposure) such that the most heavily exposed individuals are most likely to become diseased. The children received paraoccupational exposure to asbestos from dust and residue carried home on their father's skin and clothing, so their risk of asbestos-associated disease is less than his occupational risk but more than the background risk of the general population. You note that asbestos-associated disease, particularly mesothelioma, can occur with paraoccupational exposure and that there is an extremely low risk of contracting mesothelioma from the background exposures to asbestos experienced by the general population.

   The information for this answer comes from the "What Respiratory Conditions Are Associated with Asbestos?" section.