Pulmonary fibrosis is a serious condition that causes scarring of the lung tissue. This scarring occurs within the alveoli of the lungs. Alveoli are small air sacs that are responsible for exchanging oxygen and carbon dioxide with the blood. Pulmonary fibrosis can be classified as an interstitial lung disease.
Overtime, this scarring (fibrosis) causes stiffening in the lung walls. This can make it difficult to breath. Additionally, thickened lung walls reduce the body’s ability to exchange gases. This may diminish the amount of oxygen that reaches internal organs, as well as the brain. In advanced stages, pulmonary fibrosis can lead to respiratory failure and death.
Symptoms of Pulmonary Fibrosis
Labored breathing and shortness of breath are the most common symptoms of pulmonary fibrosis. For those with the illness, breathing is especially difficult following physical exertion. Other common symptoms include:
- Frequent dry cough
- Pain in the chest
- Aching muscles
- Loss of appetite
- Unexplained weight loss
Unfortunately, the majority of symptoms do no manifest until advanced stages of the illness. As such, treatment options may be diminished once the illness is finally identified. Further exacerbating late diagnosis, is the potential for patients to ignore symptoms. Coughing and fatigue can often be explained away as signs of aging or being out of shape.
Causes of Pulmonary Fibrosis
Pulmonary fibrosis occurs when the body is unable to properly repair microscopic damage that occurs in the walls of the alveoli. Typically, small amounts of damage to the alveoli can be repaired. However, when the repair process is either obstructed or overwhelmed, scarring can occur. The main causes of pulmonary fibrosis include:
Inhalation of pollutants: Repeated exposure to hazardous airborne materials, such as asbestos fiber, silica dust, tobacco smoke, grain dust, sugar cane and animal droppings can cause irritation of the lungs. These materials become lodged in the lungs, and can serve as the source for pulmonary scarring.
Medication: Some medications cause tissue damage that reduces the lungs’ ability to repair the alveoli. Chemotherapy drugs such as methotrexate and cyclophosphamide have been known to cause such side effects. Other medications linked to pulmonary fibrosis include cardiovascular drugs such as amiodarone and propanolol, antibiotics such as sulfasalazine and nitrofurantoin, and a handful of psychiatric drugs.
Radiation treatment: Lung damage can occur following radiation treatment. Such damage infrequently occurs after treatment of breast or lung cancer.
Acid reflux: Individuals with pulmonary fibrosis often have acid reflux. The condition is also known as gastroesophageal refulx disease (GERD).
Lung infection: pneumonia and tuberculosis may lead to irreparable lung damage
Tissue disorders: Other disorders linked to pulmonary fibrosis include rheumatoid arthritis, systemic lupus erythematosus, dermatomyositis, sarcoidosis, polymyositis and Sjogren’s syndrome.
Treating Pulmonary Fibrosis
There is no cure for pulmonary fibrosis. Once scarring occurs, it is irreversible. However, steps can be taken to minimize or slow additional scarring. For cases in which scarring occurs due to inhalation of pollutants, immediate steps should be taken to eliminate additional exposure (i.e. quitting smoking).
Medications may be prescribed to slow the deterioration of lung function. Immunosuppressants such as corticosteroid are generally the preferred treatment choice. However, success from these drugs may be minimal in some patients. They can also result in serious side effects, such as diabetes, glaucoma and skin cancer.
Oxygen therapy: Breathing can be made easier through oxygen therapy. Though purely palliative, such treatment can dramatically improve day-to-day function and overall health.
Pulmonary rehabilitation: Regimented programs can teach patients to overcome breathing problems that stem from pulmonary fibrosis. Rehabilitation includes a combination of exercise, breathing techniques and nutritional counseling.
Lung transplant: Younger patients may be eligible for lung transplantation. This treatment is typically reserved for patients who have responded unfavorably to all other types of treatment.
Prognosis of Pulmonary Fibrosis
It is estimated that five million individuals are affected by pulmonary fibrosis globally. Of the 500,000 pulmonary fibrosis cases in the United States, 40,000 patients die annually from the illness.
Progression of pulmonary fibrosis differs considerably from one case to another. However, once diagnosed the average survival time is two to four years. A number of factors may contribute to a dramatically longer survival time. For example, individuals younger than 50 years old and female patients are statistically more likely to live longer.
Pulmonary Fibrosis Vs. Asbestosis
When pulmonary fibrosis is caused by asbestos, it is referred to as asbestosis. As such, asbestosis is a sub-category of pulmonary fibrosis. Similarly, scarring due to silica dust is called silicosis.
See also: page on benign mesothelioma