Test your medicine knowledge with the MKSAP challenge, in partnership with the American College of Physicians.
A 45-year-old man is evaluated for a 6-month history of increasing daily cough, sputum production, and dyspnea on exertion. He has been employed as a coal miner for 10 years. He has never smoked and does not have a history of diabetes mellitus, hypertension, or hyperlipidemia. His family history is negative for cardiopulmonary disease.
On physical examination, vital signs are normal. Pulmonary examination reveals mildly decreased breath sounds bilaterally with no wheezes, crackles, or rhonchi. Cardiac examination is normal.
A chest radiograph is normal.
Which of the following is the most appropriate next step in management?
A: Annual chest radiography
B: High-resolution CT of the chest
C: PET chest imaging
D: Pulmonary function studies
MKSAP Answer and Critique
The correct answer is D: Pulmonary function studies.
The most appropriate diagnostic test to perform next is pulmonary function testing, specifically with measurement of spirometry, lung volumes, and DLCO. Exposure to coal dust in occupational settings may lead to a spectrum of clinical conditions ranging from asymptomatic deposition of coal particles without an inflammatory response (anthracosis) to complicated pulmonary disease with massive pulmonary fibrosis caused by the activation of inflammatory mediators in response to inhaled coal dust. Impairment of lung function in individuals exposed to coal dust is also significantly accelerated in smokers. Autopsy studies have shown that the extent of emphysema was significantly greater in ever-smokers who were miners in comparison with the never-smoker, non-miner population. In addition, the extent of emphysema was sixfold greater in those who were never-smoker miners compared with never-smoker non-miners. Documentation of declines in FEV1 in coal miners provides strong evidence for the development of obstructive lung disease in workers exposed to significant coal dust. As a result, symptomatic patients should undergo pulmonary function testing to identify obstructive physiology, whether or not they have a smoking history. This allows for earlier interventions such as bronchodilator therapy, avoidance of further exposure, and the opportunity for continued monitoring.
In asymptomatic patients with a history of coal exposure in whom baseline radiographs have been obtained, radiographic studies should be repeated every 5 years to monitor for progressive lung disease. These studies should be performed more frequently in patients who develop symptoms. However, initiating routine surveillance alone in this symptomatic patient without further evaluation would not be appropriate.
Although coal miners are at increased risk for interstitial lung diseases, this patient presents with bronchitic symptoms and a normal chest radiograph. Before pursuing CT imaging, pulmonary function testing should be performed to differentiate between obstructive and restrictive physiology.
The role of PET scanning for the diagnosis and surveillance of lung disease associated with coal exposure has not been established. Because of its high sensitivity for detection of inflammation, its use in assessing malignancy in coal-exposed patients is limited owing to high false-positive rates.
- Studies have shown that workers exposed to significant coal dust have a high risk for the development of obstructive lung disease.
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