Professor of Pulmonary Medicine
Division of Pulmonary and Critical Care Medicine
Medical University of South Carolina
Charleston, South Carolina

Question: I am a PCP with a 72 y/o patient. The pulmonologist made a diagnosis of IPF based on radiologic findings. She stressed the extensive honeycombing of the lungs. What is honeycombing and what is the underlying physiology?

Answer: This is the million dollar question to the pathogenesis of Idiopathic Pulmonary Fibrosis (IPF). Briefly, honeycombing is a word applied to the appearance on the computed tomography (CT) scan that applies to the development of adjacent cystic airspace enlargement, usually in a subpleural location. As pulmonary specialists and radiologists, we use many words that do not have formal definitions and "honeycombing" is one of these words. In brief, it looks like a "honeycomb."

Question: I never know when to order an antinuclear antibody (ANA) or rheumatoid factor (RF) test on my interstitial lung disease (ILD) patients or what to do with a positive test. Please help!

Answer: Many pulmonary physicians choose to screen for occult connective tissue disease (CTD) with a variety of laboratory tests. The practice has evolved from the knowledge that 10% to 25% of ILD patients will eventually be diagnosed with a CTD; however, the frequency with which ILD is the only manifestation of a CTD remains unknown. Usually a CTD will evolve in the first 2 years following ILD presentation in these patients.

Question: My doctor tells me that my construction job has contributed to my pulmonary fibrosis. Is this true? Should I change jobs?

Answer: First of all, this is a complicated question that depends on many aspects of the job and what kind of "pulmonary fibrosis" is present. The best way to answer the question is to explore some of the occupational interstitial lung diseases. For starters, we know that some kinds of dust can cause pulmonary fibrosis.

One common cause is asbestos, which is being systematically removed from many old buildings. An exposure to asbestos sufficient to cause pulmonary fibrosis comes with daily exposure for many years to a significant dust burden. This can be seen in automobile brake workers, plumbers, and demolition experts who do not wear masks. The lung disease is called "asbestosis." If an x-ray shows calcium deposits along the pleura (the outside lining of the lung), asbestosis is suspected.

Another mineral that can cause lung disease is silica, which is different from silicone. Silica is a hard rock that is the principal component of sand and quartz. Therefore, quarry workers, sandblasters, and others with exposure to rock dust have a risk for this disease. The disease "silicosis" is characterized by small nodules that are most common in the upper parts of the lung.

Other minerals can also cause lung disease. Found in hardened metals, cobalt causes giant cell interstitial pneumonitis, a disease with a characteristic biopsy. Coal causes coal worker's pneumoconiosis, a disease that is much more symptomatic when mixed with silicosis.

Last, it has been noted that idiopathic pulmonary fibrosis (IPF) is seen more commonly in some occupations that have contact with dust. Whether there is some particular component of dust that scars the lungs, or whether IPF is the result of a more generalized response to a dusty environment remains unknown. Unfortunately, there is no information on whether removal from a dusty environment is beneficial to an established IPF patient. The general recommendation of working in a clean air environment makes some common sense, but has never been subjected to study.

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