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Q. What is an interstitial lung disease?
An interstitial lung disease (ILD) is a type of lung disease that results from an increase in the walls of the tiny airspaces in the lung. There are many types of interstitial lung diseases and they can be divided into known and unknown (idiopathic) categories. Some medical conditions known to cause ILD include environmental or occupational exposures including asbestos or other particulates, inflammatory conditions such as sarcoidosis, and autoimmune or rheumatologic conditions such as rheumatoid arthritis or lupus. There are more than 200 related diseases of the lung known as interstitial lung diseases (ILD), which are also referred to as diffuse parenchymal lung diseases or DPLD. Because these diseases affect the interstitium — the walls of the air sacs of the lung — ILDs are classified as a group. However, ILDs may also affect other parts of the lungs. Many ILDs have similar characteristics to IPF and most result in lung fibrosis.
If there is a clear association with another illness or the lung scarring (fibrosis) is the result of a side effect from a medication or an exposure to an agent known to cause PF, then the cause of the disease is no longer considered idiopathic. PF clearly associated with another disease, such as scleroderma or rheumatoid arthritis, would be referred to as pulmonary fibrosis secondary to scleroderma or secondary to rheumatoid arthritis.
Any ILD that is not associated with any of the known causes is referred to as an idiopathic interstitial pneumonia (IIP). The word pneumonia is used to describe inflammation and not an infection such as bacterial pneumonia. IIP is further broken down into a number of pathological subtypes. These subtypes include usual interstitial pneumonia (UIP), non-specific interstitial pneumonia (NSIP), desquamative interstitial pneumonia (DIP), respiratory bronchiolitis-associated interstitial lung disease (RB-ILD), acute interstitial pneumonia (AIP), cryptogenic organizing pneumonia (COP), and lymphocytic interstitial pneumonia (LIP). IPF is a subtype of IIP, the pathological pattern seen in IPF is UIP.
It is important to determine the underlying cause of the interstitial lung disease when possible because it may have any important impact on prognosis and treatment.
Q. How common is pulmonary fibrosis?
There are many kinds of pulmonary fibrosis. The incidence and prevalence of the individual types of pulmonary fibrosis is largely based on etiology. Idiopathic pulmonary fibrosis affects over 200,000 people in the US and many more worldwide. The incidence of pulmonary fibrosis in the US is been reported to be between 11 and 20 per 100,000 among men, and between 7 and 13 per 100,000 among women.
Incidence and Prevalence of Idiopathic Pulmonary Fibrosis.Ganesh Raghu, Derek Weycker, John Edelsberg, Williamson Z. Bradford, and Gerry Oster. Am J Respir Crit Care Med Vol 174. pp 810–816, 2006.
Q. Why does IPF occur?
Idiopathic pulmonary fibrosis has no known cause. There are many theories as to why patients develop pulmonary fibrosis and still more as to why some patients have a more rapid decline in lung function than others. Gastro-esophageal reflux disease (GERD), viral infections, genetic susceptibilities, and oxidant lung injury are some of the proposed initiators and/or exacerbators.
Further Reading
Determinants of initiation and progression of idiopathic pulmonary fibrosis. Kottmann RM, Hogan CM, Phipps RP, Sime PJ. Respirology. 2009 Sep;14(7):917-33. doi: 10.1111/j.1440-1843.2009.01624.x. Review.PMID:19740254
Q. What is the difference between pulmonary fibrosis and chronic obstructive lung disease (COPD)/emphysema?
COPD/Emphysema is chronic lung disease that in the United States is most often associated with tobacco smoke. COPD/Emphysema can coexist with pulmonary fibrosis, as smoking is also a risk factor for developing pulmonary fibrosis. In contrast to pulmonary fibrosis, COPD/emphysema results in the loss of lung tissue which results in a decrease in lung surface area and therefore impairs gas exchange in the lung. COPD/Emphysema also results in easily collapsible lung tissue and airways thereby resulting in chronic airflow "obstruction."
Q. How does oxygen therapy impact progression of the disease?
Supplemental oxygen may eventually be necessary if oxygen saturation levels decreased below 88%. This may first occur during periods of exertion. It is therefore important to test whether oxygen levels decrease while walking or exercising. Patients who have exertional or resting oxygen desaturations often feel less short of breath if they wear supplemental oxygen and can therefore significantly improve quality of life. It is not clear whether the use of supplemental oxygen has any impact on disease progression.
Q. What about air travel or travel to locations with elevated altitude?
Airplanes rely on pressurized cabins to maintain passengers comfort during flight. The cabins are typically pressurized to about 8000 feet. This means that during the flight passengers are essentially at an altitude of 8000 feet. Because the pressure at this altitude is less than at sea level, it is more difficult to maintain oxygen saturations. Even if you do not require supplemental oxygen at sea level, you may require supplemental oxygen at altitude. If you have lung disease, it is important to discuss with your doctor whether you may need oxygen during a flight or when visiting a location with an elevated altitude.
Q. What are the implications, so far, of gastro-esophageal reflux disease (GERD) in pulmonary fibrosis?
GERD has been implicated as a potential initiator of exacerbator of pulmonary fibrosis. Clinical trials are being conducted to determine the impact of GERD on IPF. Current recommendations include the treatment of GERD in all patients who have pulmonary fibrosis and GERD.
Q. How is sleep apnea connected to pulmonary fibrosis?
We now recognize that sleep apnea is very prevalent in patients with pulmonary fibrosis. It is recommended that patients with pulmonary fibrosis be screened for sleep disorders and be treated as applicable.
Q. What is the PFF Care Center Network?
The Pulmonary Fibrosis Foundation (PFF) is a national organization dedicated to the care of patients with all forms of pulmonary fibrosis. The PFF is focused on improving access to expert pulmonary fibrosis care including improving diagnosis and management of patients with pulmonary fibrosis. They are also dedicated to expanding pulmonary fibrosis research to develop new treatments.
Q. What exactly is a PFF Patient Care Center and how will UR Medicine be unique in their implementation and patient support?
The University of Rochester was inducted into the PFF Care Center Network in November 2015. The PFF-CCN is a network of 40 academic institutions across the US designated as sites of excellence for the care of patients with pulmonary fibrosis. The UR PFF-CCN is a comprehensive center dedicated to the care of patients with all forms of ILD and pulmonary fibrosis. The center will provide world class expertise in the diagnosis and management of ILD/PF. Patients at the center will have direct access to anti-fibrotic medications through the UR’s specialty pharmacy and will have a dedicated pharmacist following their treatment(s). Patients will have access to clinical trials and numerous opportunities to participate in a variety of other clinical research projects. Any patient being evaluated at the UR PFF-CCN will be encouraged to participate in this national patient registry that has been developed as an observational study intended to improve our understanding of the natural progression of IPF and other forms of pulmonary fibrosis. They will have access to the local PF support group, pulmonary rehabilitation facilities and be invited to attend local educational opportunities sponsored by the center. The center will also serve the entire upstate New York community by offering consultation services at patient’s or other care givers requests.