Definition of Diffuse interstitial lung disease:

Diffuse interstitial lung disease refers to a group of lung disorders in which the deep lung tissues become swollen and scarred.

Causes, incidence, and risk factors:

Interstitial lung diseases (ILD) are caused by swelling and scarring of the air sacs (alveoli) and their supporting structures (the interstitium). This leads to reduced levels of oxygen in the blood.

The interstitial lung diseases can be broken down into two large groups:

• Those that have no known cause (idiopathic ILD)
• Those with an identifiable cause

One recent system further divides idiopathic ILD into the following three groups:

• Idiopathic pulmonary fibrosis/usual interstitial pneumonitis (IPF/UIP)
• Nonspecific interstitial pneumonitis (NSIP)
• Acute interstitial pneumonitis (AIP)

There are dozens of different causes of ILD. Many occupational substances can cause ILD, including:

• Asbestos
• Coal dust
• Cotton dust
• Sand (silica) dust

People who are heavily exposed to known causes of occupational lung disease in the workplace are usually routinely screened for lung disease. This can include coal miners, sand-blasters, ship workers, and others.

Occasionally, bird keeping or bathing in hot tubs may cause some forms of ILD.

The following diseases can cause ILD:

• Lupus
• Rheumatoid arthritis
• Sarcoidosis
• Scleroderma

Certain medications (such as bleomycin, amiodarone, and methotrexate) may also cause ILD.

Cigarette smoking may increase the risk of developing some forms of ILD and may cause the disease to be more severe.