Interstitial Lung Disease (Interstitial Pneumonitis)

• Interstitial lung disease includes a group of diseases that have thickening of the supporting tissues between the air sacs of the lungs. This thickening can be due to a variety of causes such as:
  • Associated autoimmune or collagen vascular diseases
  • Exposure to medications or toxins such as asbestos, tobacco smoke, or environmental toxins
  • Associated genetic diseases
  • The cause is not known (idiopathic).
  • The most common symptoms of interstitial lung disease are a dry cough and shortness of breath.
• The diagnosis of interstitial lung disease typically involves imaging tests, measurement of blood oxygen levels, and sometimes, biopsies or tissue sampling.
• Some forms of interstitial lung disease lead to irreversible scarring and respiratory failure.
• Treatment can involve corticosteroid medications to reduce inflammation.
• The prognosis of interstitial lung disease depends on the precise cause.
• Some cases of interstitial lung disease do not have an identifiable cause and are referred to as idiopathic.

Interstitial lung disease includes a group of diseases that have thickening of the supporting tissues between the air sacs of the lungs as the common factor. The interstitium is a thin layer of tissue that is normally appears as a fine lace on X-rays or imaging studies (best visualized as the appearance of a sponge).

Interstitial lung disease results from a variety of causes that lead to thickening of the supporting tissue around the air sacs rather than the air sacs themselves. Interstitial lung disease usually involves all of the lungs diffusely rather than affecting only one area.

Disease of the interstitium is recognized on imaging studies as a thick lace (sponge), sometimes symmetric, and in other types, scattered and irregular.

Several terms related to interstitial lung disease have been used to describe this condition, including "interstitial pneumonia." However, since "pneumonia" is usually associated with an infection, some doctors choose to use the term "interstitial pneumonitis" to refer to inflammation in the interstitial space since many of the causes of this inflammation are not infections. "Interstitial fibrosis" is the term used to refer to the scarring of the lungs that can result from prolonged interstitial inflammation. Interstitial lung disease can be acute (coming on suddenly) or chronic (occurring over time).