What is CTD-ILD?

CTD-ILD or connective tissue disease associated interstitial lung disease (ILD) is a diagnosis term. Connective tissue diseases are a group of autoimmune conditions which may affect various organs of the body. They are called autoimmune because the body’s immune system produces antibodies which abnormally target healthy tissues. An antibody is a specific type of protein produced by immune cells to help direct the immune response.

The term connective tissue refers to certain protein structures which support the cells of the various organs of the body. The connective tissue contains proteins such as collagen or elastin. You may find terms such as collagen vascular disease or other ways to refer to such conditions.

In connective tissue disease, because the same antibody type can target a similar structure which may be present in several organs of the body, symptoms or signs of illness may appear in various organs at the same time. This can make for a complicated diagnosis, as several health problems may initially appear unrelated to each other, until the autoimmune cause is identified. There are a large number of connective tissue diseases which may be diagnosed, each behaving in a slightly different way.

Examples of connective tissue diseases include systemic sclerosis, rheumatoid arthritis, polymyositis and dermatomyositis etc.

One major feature of several such conditions is the development of interstitial lung disease. In some cases, the ILD appears after the onset of the connective tissue disease in other organs, but in other cases, the lung involvement may precede other symptoms.

A complete diagnosis of CTD-ILD generally involves a joint approach between the pulmonology/respiratory and the rheumatology teams. Treatment is also generally conducted jointly, as various treatments may need to be given, potentially for lung fibrosis as well as to control the autoimmune inflammation.