Interstitial Lung Disease (ILD) Facts
What are interstitial lung diseases?
Interstitial lung disease, or ILD, is a common term that includes more than 100 chronic lung disorders, which may be:
- Nonmalignant (non-cancerous)
- Noninfectious
Interstitial lung diseases are named after the tissue between the air sacs of the lungs called the interstitium -- the tissue affected by fibrosis (scarring).
Interstitial lung diseases may also be called interstitial pulmonary fibrosis or pulmonary fibrosis.
The symptoms and course of these diseases may vary from person to person, but the common link between the many forms of ILD is that they all begin with an inflammation.
- Bronchiolitis. Inflammation that involves the bronchioles (small airways).
- Alveolitis. Inflammation that involves the alveoli (air sacs).
- Vasculitis. Inflammation that involves the small blood vessels (capillaries).
There are about five broad categories of Interstitial Lung Diseases:
- Exposure or occupational related ( asbestosis, silicosis, hypersensitivity pneumonitis)
- Treatment related: chemotherapy, radiation, some medications
- Autoimmune or connective tissue diseases: Lupus, Scleroderma, Poly or dermatomyositis, rheumatoid arthritis-related ILD
- Sarcoidosis
- Idiopathic ILDs
The other types are:
- Sarcoidosis
- Idiopathic pulmonary fibrosis (idiopathic means a disease for which a cause is unknown)
- Bronchiolitis obliterans
- Histiocytosis X
- Chronic eosinophilic pneumonia
- Collagen vascular disease
- Granulomatous vasculitis
- Goodpasture's syndrome
- Pulmonary alveolar proteinosis
How does interstitial lung disease occur?
In interstitial lung disease, the lung is affected in three ways:
- Lung tissue is damaged in some known or unknown way.
- The walls of the air sacs in the lungs become inflamed.
- Scarring (fibrosis) begins in the interstitium.
Fibrosis results in permanent loss of that tissue's ability to breathe and carry oxygen. Air sacs, as well as the lung tissue between and surrounding the air sacs, and the lung capillaries, are destroyed by the formation of scar tissue.
The diseases may run a gradual course or a rapid course. People with ILD may notice variation in symptoms -- from very mild, to moderate, to very severe. The condition may remain the same for long periods of time or it may change quickly. The course of ILDs is unpredictable. If they progress, the lung tissue thickens and becomes stiff. The work of breathing then becomes more difficult and demanding. Some of the diseases improve with medication if treated when inflammation occurs. Some people may need oxygen therapy as part of their treatment.
What causes interstitial lung diseases?
The cause of interstitial lung disease is not known; however, a major contributing factor is thought to be inhaling environmental or occupational pollutants such as inorganic or organic dusts.
Other contributing factors include:
- Sarcoidosis
- Certain drugs or medications
- Radiation
- Connective tissue or collagen diseases
- Family history