Interstitial lung disease (ILD) refers to a group of diseases that irritate, inflame or scar the lungs and supporting air sacs. When this scarring (or pulmonary fibrosis) occurs, it can cause stiffness in the lungs, making it difficult for a person to breathe enough oxygen into the bloodstream.

The Yale Medicine Interstitial Lung Disease Program focuses on bringing together specialists from different disciplines, including pulmonary pathologists, chest radiologists, rheumatologists and occupational medicine physicians, to provide patients with the best care. 

Interstitial lung disease refers to a group of more than 200 lung disorders. These can be caused by breathing in dangerous particles (such as from occupational exposure to fumes, gases, or molds) or dust in the air. The condition can also be set off by autoimmune disease, medication and some types of radiation. Other cases may be caused by inherited genes. Physicians at Yale also see patients with sarcoidosis, a type of lung disease that causes lumps to develop in the lungs and lymph nodes. When the disease develops for unknown reasons, it is called idiopathic pulmonary fibrosis.  

Often, a patient will first go to a primary care doctor with breathing problems such as a dry cough or shortness of breath even at rest. When symptoms begin to impede daily life, it may signal that the lungs have already been damaged. The doctor will discuss medical and personal family history and recommend further tests to zero in on the root cause.

There is no way to reverse the scarring from interstitial lung disease. Treatment options often involve easing symptoms or slowing down the disease’s progression, but are not typically successful at stopping the disease entirely.

The doctor may recommend imaging tests, blood tests, breathing tests and possibly a biopsy to sample and test tissue.

Imaging tests could include:

• X-ray of the chest, to find lung damage in patterns that suggest interstitial lung disease
• Computerized tomography (CT) scan, to obtain cross-sectional images to view the lung damage and identify any patterns
• Echocardiogram, a sonogram of the heart that uses sound waves to test how well the heart is working and to gauge the pressure on the left and right sides of the heart

Breathing tests may include:

• Spirometry, in which the patient exhales forcefully into a tube and machine that measures the amount the lungs’ capacity
• Oximetry, where a device is placed on a finger to measure oxygen saturation in the blood while the patient walks

Additionally, a physician may request a biopsy, or sample of lung tissue, in order make an accurate diagnosis. 

With a biopsy, a small amount of lung tissue is extracted and sent to a pathologist at a laboratory, who will study the tissue sample under a microscope. The procedure is requested if the doctor wants to more closely examine a patient’s pulmonary fibrosis, or the scarring of the lungs that occurs when abnormal healing responses are initiated.

“To obtain tissue for diagnosis, there are several methods a doctor can use do this,” says Yale Medicine pathologist Robert Homer, MD, PhD.

The different possibilities could include one of the following:

Bronchoscopic biopsy. A flexible tube (or bronchoscope) is pushed down the patient’s throat to the lungs, where it then removes a tissue sample smaller than the head of a pin. “This is mainly used for cancer, but a few interstitial lung diseases can also be diagnosed this way,” Dr. Homer says. 

Cryobiopsy. “This is a technique that allows us to remove more tissue from the lung to test and study,” Dr. Homer notes.

Surgical Biopsy. With this more serious, more invasive procedure, the doctor can obtain a larger sample. It’s removed from the lung by inserting a small camera and surgical tools through incisions between the ribs.

A pathologist will look under the microscope to analyze the tissue sample. “This requires much skill, because you have to get the most information possible often from very small specimens of tissue,” Dr. Homer says. “You also want to make the most efficient use of time to provide the pathology report with the most diagnostic confidence."

Some anti-inflammatory and auto-immune medications may help alleviate the symptoms. Oxygen therapy also helps to improve breathing and blood flow, even if it is unable to provide a cure. 

Our experts take a multidisciplinary approach to diagnosing and treating lung diseases and have expertise in interstitial lung disease, occupational lung disease, lung radiology and lung pathology.

“Lung diseases can be difficult to diagnose and treat,” Homer says. “There are not many of these lung specialty clinics in the U.S. with highly specialized pulmonary pathologists who look at a high volume of lung biopsies. I've been evaluating them at Yale for over 20 years.”