ILD – Information for Patients

Interstitial lung disease (ILD), also known as diffuse parenchymal lung disease, describes a range of disorders that affect the lining of the alveoli (air sacs) in the lungs. Normally, the alveoli expand and contract with ease. Oxygen is absorbed into the bloodstream through the lining of the alveoli (the "interstitium"). 

In patients with ILD, there is progressive inflammation and/or scarring (fibrosis) of the interstitium. This inflammation and scarring eventually limit the ability of the lungs to expand and adequately absorb oxygen.


Symptoms in patients with ILD tend to develop gradually. Often the only initial symptom is shortness of breath with aerobic activity (such as exercise, walking, or climbing stairs). Over time, however, shortness of breath can occur with even minimal activity or at rest. A dry cough and/or general feelings of fatigue, weakness, and malaise may also occur.


There are many known causes of interstitial lung disease. These can include:

  • exposures in the home or workplace (such as parakeets or asbestos)
  • connective tissue diseases (such as lupus, scleroderma, or rheumatoid arthritis)
  • use of certain medications
  • radiation exposure
  • smoking

Some patients have a familial predisposition to ILD. However, in many cases, doctors do not know what causes a patient's ILD. In these cases, the disease is called "idiopathic. There are a number of idiopathic ILDs, though the most common one is idiopathic pulmonary fibrosis (IPF).

Diagnosis of ILD

Identifying the type of ILD that a patient has can be a challenging process. The goal of the ILD team at NewYork-Presbyterian Hospital/Columbia University Medical Center is to complete each patient's diagnostic evaluation in a thorough, efficient, and expedient manner.

The evaluation begins with a physical exam, blood tests, a chest x-ray, a chest CT scan, and pulmonary function testing. If a diagnosis cannot be made using these tests, a lung biopsy is often necessary. Lung biopsies can be performed in two ways.

  • Bronchoscopy. A same-day procedure, during bronchoscopy a flexible tube (about the diameter of a pen) is inserted through a nostril and advanced into the tracheobronchial tree of the lungs. Small lung tissue samples can be removed during this procedure. The patient receives an anesthetic to maintain comfort during this procedure.
  • Surgical Biopsy: Some types of ILD are more amenable to diagnosis by bronchoscopy than others. For those diseases that are not easily diagnosed by bronchoscopy, a surgical lung biopsy may be necessary (See the figure for a comparison of healthy and diseased lung tissue).

Lastly, exercise testing (such as a cardiopulmonary exercise test and a six-minute walking test) will be performed to help gauge the severity of disease.

Once diagnostic testing is complete, each case is presented and discussed at a multidisciplinary ILD conference, where an expert group of clinicians and researchers achieve a consensus on the diagnosis and treatment plan for each patient.


The treatment of ILD depends on the degree of inflammation and scarring. Inflammation may be reversible or controlled with medical therapies such as steroids (like prednisone) or stronger medications, called immunosuppressive agents (such as azathioprine, mycophenelate mofetil, or cytoxan). The decision to use steroids or immunosuppressive medications depends on each patient's unique situation. An ILD specialist will discuss the risks and benefits of potential treatments with each patient.

For some patients, inflammation is present at very low levels or not at all, and scarring (fibrosis) predominates. In these cases, steroids or immunosuppressive therapy are unlikely to be beneficial because lung scarring is usually irreversible. Some antifibrotic agents have been studied (such as pirfenidone) or are being studied (like N-acetylcysteine) for the treatment of idiopathic pulmonary fibrosis. However, to date, the FDA has not approved any antifibrotic agents for use in the treatment of patients with ILD. For those with progressive fibrosis, clinical trials of investigational agents and/or referral for lung transplantation may be treatment options. 

Supportive therapies for ILD include the use of supplemental oxygen, pulmonary rehabilitation, treatment of coexisting pulmonary conditions (such as chronic obstructive pulmonary disease or obstructive sleep apnea) and or complications of ILD (such as pulmonary hypertension).

Your First Visit

Your first visit will last approximately half a day. Prior to your visit, you will receive a phone call from our administrative assistant, who will review your itinerary for the day and then mail a hard copy of the schedule to you. The following is a description of what you can expect during your first visit.

  • Your day will begin with testing (echocardiogram, chest x-ray, pulmonary function testing, six-minute walk test, and blood tests).
  • You will subsequently meet with one of our ILD physicians and have a detailed medical history taken and a physical examination performed. Your visit with the ILD physician will last approximately 45 to 60 minutes. 
  • Our research coordinator will meet with you to discuss the opportunity to enroll in our research database.

We ask that you bring all available records to this visit, including CDs of outside chest x-rays and CT scans, pulmonary function test reports, echocardiogram reports, blood test results, bronchoscopy results, and slides from lung biopsies done at other hospitals. Our administrative assistant will speak with you by phone to guide you and your referring physician’s office through the records needed prior to your visit.

Thank you for choosing our center for your evaluation. We look forward to participating in your care.