Pulmonary fibrosis means scarring of the lung. Many diseases can cause pulmonary fibrosis including infections, radiation therapy, certain medications, certain job occupations, and some diseases such as rheumatoid arthritis, scleroderma, mixed connective tissue disease, and systemic lupus erythematosus. The most common cause of pulmonary fibrosis is idiopathic pulmonary fibrosis (pulmonary fibrosis of unknown cause).
Patients with pulmonary fibrosis develop a scarring process in the lungs. Once scarring sets in, medications can do very little for the disease. The most common symptoms of pulmonary fibrosis are shortness of breath, particularly with activities, and cough. The fibrosis is usually first suspected by your physician when he or she hears "crackles" when listening to your lungs (sounds which are similar Velcro being torn apart) or when he or she sees scarring on a chest x-ray.
To confirm of a diagnosis of pulmonary fibrosis, a high resolution chest CT scan is often performed as it can sometimes determine the cause of the fibrosis and it can also lead the lung specialist to the best part of the lung for biopsy. Blood tests may be done to help the physician check for autoimmune diseases such as rheumatoid arthritis. The next step is frequently a bronchoscopy with bronchoalveolar lavage and transbronchial biopsy. Bronchoalveolar lavage is a technique where the lung is rinsed out and the rinsings are analyzed in the laboratory for the type of inflammation present, evidence of cancer cells, and evidence of certain infections. A transbronchial biopsy is performed through the bronchoscope and yields small, pinhead-sized pieces of lung, which can be looked at under the microscope to determine the cause of fibrosis. All in all, high resolution CAT scan and bronchoscopy will yield a firm diagnosis in less than half of the cases. If the diagnosis remains uncertain, then surgical lung biopsy is often performed. This is done by being admitted to the hospital, taken to the operating room, being put under general anesthesia, and having an incision made by a surgeon in the chest to remove thumbnail-sized pieces of lung for microscopic analysis.
To determine the stage of the pulmonary fibrosis, pulmonary function studies, and sometimes pulmonary exercise tests are performed to determine how severely the fibrosis is affecting your lung function. Pulmonary function studies are frequently performed periodically to determine whether the lungs are responding to treatment. These tests will usually consist of spirometry (to measure lung flow rates), lung volumes, diffusing capacity (to measure how well oxygen and other gases get from the air you breath into your bloodstream), and a 6 minute walk test (to measure your oxygen level when exercising and to measure your exercise endurance).
The treatment of pulmonary fibrosis varies depending on the cause of pulmonary fibrosis. In the past, the main approach in the medical treatment of pulmonary fibrosis was to stop inflammation in hopes of stopping future scarring. In some forms of pulmonary fibrosis, stopping inflammation does prevent fibrosis but in other forms, the fibrosis develops without inflammation and anti-inflammatory drugs have little effect. For idiopathic pulmonary fibrosis, we often start with prednisone (an oral corticosteroid medication) plus sometimes either azathioprine or cyclophosphamide. These medications are usually given a trial of three to six months and if there is no benefit, then they are discontinued. For more information on these medications, please refer to the Web file on oral corticosteroids, azathioprine, and cyclophosphamide. For the most common form of pulmonary fibrosis (usual interstitial pneumonitis), these drugs work at best in only about 8% of patients.
Interferon gamma-1b has been used in the past to treat idiopathic pulmonary fibrosis but was shown in a recent study (March, 2007) to not be effective.
N-acetylcysteine (NAC) is an anti-oxidant that has been shown to improve patients with idiopathic pulmonary fibrosis when combined with prednisone and azathioprine. It is not clear whether it also has any benefit by itself or when combined with other drugs such as gamma interferon. It is inexpensive and causes few side effects. It is purchased over the counter at nutrition and health food stores and is taken as a 600 mg capsule three times a day.
Pirfenidone is an experimental medication that is currently being evaluated for use in idiopathic pulmonary fibrosis. It is only available by enrollment in a clinical trial that we are participating in; more information about it can be found at:
http://home.columbus.rr.com/allen/CAPACITY.htm
Esophageal reflux has been associated with worsening of pulmonary fibrosis in some studies. It is not clear whether the esophageal reflux is caused by the worsened fibrosis or whether it causes the worsened fibrosis. Nevertheless, we generally recommend treatment of reflux with medicines called proton pump inhibitors if there is any sign of acid reflux (such as heartburn).
As the scarring advances, the lung's ability to transport oxygen from the air we breathe into the blood stream becomes diminished and supplemental oxygen is often necessary. Initially, this usually means oxygen to use with exercise but can advance to the point that oxygen is required at rest as well.
If the pulmonary fibrosis continues to advance despite medical therapy, lung transplantation is often considered. Persons who are candidates for lung transplant from pulmonary fibrosis are generally those who are under the age of 65 and who have developed the need for supplemental oxygen.
Certain types of pulmonary fibrosis advance more slowly than others. For example, pulmonary fibrosis associated with scleroderma tends to have a more benign course and responds better to therapy; it can often be put into remission permanently. Certain types of idiopathic pulmonary fibrosis have a more favorable prognosis, also. There are several types of idiopathic pulmonary fibrosis, which we define by the microscopic appearance of the lung after lung biopsy. Desquamative interstitial pneumonitis has the most favorable prognosis and is almost always caused by tobacco smoke. Smoking cessation and corticosteroids generally result in complete or partial resolution. Respiratory bronchiolitis interstitial lung disease has the next most favorable outcome and is also caused by tobacco smoke. It also is generally treated with smoking cessation with or without corticosteroids. Nonspecific interstitial pneumonitis has a variable response to steroids and/or cyclophosphamide. Usual interstitial pneumonitis occasionally responds to cyclophosphamide and corticosteroids, however, it is the least responsive and often progresses despite early drug treatment. N-acetylcysteine as well as a number of experimental drugs (such as pirfenidone) offer promise for treatment in the future.
Patients with pulmonary fibrosis can develop a number of respiratory and nonrespiratory symptoms which can often be annoying. Cough can be very difficult to control and often requires narcotic based cough suppressants. Depression is quite common in this disease and antidepressants are frequently used when depression is suspected. Supplemental oxygen can greatly improve exercise tolerance and can relieve the sensation of breathlessness. Because of the reduced exercise tolerance, patients often become deconditioned (out of shape) and pulmonary rehabilitation programs can be very useful in order to help you use your muscles most efficiently.
Often what patients need most is information. This includes satisfactory confirmation of the diagnosis, an honest assessment of the prognosis, and risks and benefits to be reasonably expected from treatment. In this regard, community resources such as the American Lung Association can supplement some of information provided by your physician.
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