Medical Edge Newspaper Column

Finding the Cause of Interstitial Lung Disease Not Always Possible

January 27, 2012
Dear Mayo Clinic:
My mother has been coughing for months and finally went to her doctor. She was told she may have interstitial lung disease and should see a specialist. What is this? Is it curable or will she have it forever?

Answer:
Interstitial lung disease is a term used to describe a large group of disorders that cause scarring and inflammation within the lungs. Diagnosing interstitial lung disease can be challenging, so it would be advisable for her to seek care from a lung specialist who has experience identifying and treating the disease. Some forms of interstitial lung disease are serious, progressive disorders, while others are not.

Some interstitial lung diseases have an identifiable cause. The disease may result from lung damage caused by toxins or pollutants in the air or by an underlying medical condition such as lupus, rheumatoid arthritis or scleroderma. Certain medications and some medical treatments such as radiation therapy can sometimes result in long-term lung damage that leads to interstitial lung disease. But, in many cases, pinpointing an exact cause is impossible.

Whatever the cause, interstitial lung disease seems to develop when lung damage triggers an abnormal healing response. This response results in the tissue around the lungs' air sacs, called alveoli, becoming thick and scarred, a condition known as pulmonary fibrosis. The scarring can result in a persistent cough and makes it difficult for oxygen to get into the bloodstream. That lack of oxygen can lead to symptoms that include shortness of breath.

Because many conditions fall into the category of interstitial lung disease, and because its symptoms are similar to many other lung problems, diagnosis can be difficult. A variety of tests are usually needed to rule out other lung disorders, including blood tests, imaging studies — such as a chest X-ray or a computerized tomography (CT) scan — and lung function tests. Once other possible disorders have been ruled out, accurately identifying interstitial lung disease may require obtaining a sample of lung tissue that can be examined in a laboratory.

If your mother is diagnosed with this disease, treatment may improve her symptoms. If the interstitial lung disease is determined to be caused by a medication or an environmental exposure, eliminating the drug or environmental factor may sometimes suffice in treating the disease. Medications such as corticosteroids to decrease inflammation and drugs that help suppress the immune system are often used to treat interstitial lung disease. In addition, oxygen therapy can ease breathing problems and help the body get the oxygen it needs.

Pulmonary rehabilitation can also be quite helpful for people who have ongoing breathing problems caused by interstitial lung disease. The goal of this therapy is to make day-to-day life easier and more manageable. Pulmonary rehabilitation typically focuses on exercise, breathing techniques, nutritional guidance and emotional support.

When other treatments do not improve symptoms and the condition continues to get worse, a lung transplant may be a possibility for some people who have interstitial lung disease. But a lung transplant is usually used only as an option of last resort in severe cases.

In your mother's situation, the best next step is to see a lung specialist who can help accurately identify what is causing her symptoms. If it is interstitial lung disease, that specialist can work with her to create a plan for evaluation and treatment that best fits her needs.

— Jay Ryu, M.D., Pulmonary and Critical Care Medicine, Mayo Clinic, Rochester, Minn.