Interstitial Lung Disease: Pulmonary Fibrosis

What is interstitial lung disease?

Interstitial lung disease refers to a group of about 100 chronic lung disorders characterized by inflammation and scarring that make it hard for the lungs to get enough oxygen. The scarring is called pulmonary fibrosis.

The symptoms and course of these diseases may vary from person to person. The common link between the many forms of the disease is that they all begin with inflammation.

  • Bronchiolitis: inflammation of the small airways (bronchioles).
  • Alveolitis: inflammation of the air sacs where oxygen and carbon dioxide exchange in the blood takes places (alveoli).
  • Vasculitis: inflammation that involves the small blood vessels (capillaries).

Fibrosis leads to permanent loss of your lung tissue’s ability to carry oxygen. The air sacs, as well as the lung tissue around the air sacs and the lung capillaries, are destroyed when the scar tissue forms.

The disease may run a gradual course or a rapid course. People who have it may notice variation in symptoms, from very mild to moderate to very severe. The condition may stay the same for a long time or it may change quickly. The course of the disease is unpredictable. If it progresses, the lung tissue thickens and becomes stiff, making breathing more difficult.

What causes interstitial lung diseases?

The cause of interstitial lung disease is not known. Major contributing factors include:

  • Smoking
  • Certain drugs or medicines
  • Exposure to substances at work or in the environment such as organic or inorganic dusts
  • Certain connective tissue or collagen diseases and sarcoidosis
  • Family history
  • Radiation treatment

What are the symptoms of interstitial lung diseases?

Each person may experience interstitial lung disease differently, but the most common symptoms include:

  • Shortness of breath, especially with activity
  • Dry, hacking cough that does not produce phlegm
  • Extreme tiredness and weakness
  • Loss of appetite
  • Unexplained weight loss
  • Discomfort in the chest
  • Labored breathing, which may be fast and shallow
  • Bleeding in the lungs

The symptoms of interstitial lung diseases may look like other lung conditions or medical problems. Talk with your healthcare provider for a diagnosis.

How are interstitial lungs diseases diagnosed?

In addition to a complete medical history and physical exam, the healthcare provider may also request pulmonary function tests. These tests help to measure the lungs’ ability to move air into and out of the lungs. They may include:


A spirometer is a device used to check lung function. Spirometry is one of the simplest, most common tests. It may be used to:

  • Determine how well the lungs receive, hold, and move air
  • Look for lung disease
  • See how well treatment is working
  • Determine the severity of a lung disease
  • Find out whether the lung disease is restrictive (decreased airflow) or obstructive (disruption of airflow)

Peak flow monitoring

This device is used to measure the how fast you can blow air out of the lungs. Disease-related changes can cause the large airways in the lungs to slowly narrow. This will slow the speed of air leaving the lungs. This measurement is very important in evaluating how well or how poorly the disease is being controlled.

Chest X-rays

This test takes pictures of internal tissues, bones, and organs.

Blood tests

Arterial blood gas may be done to check the amount of carbon dioxide and oxygen in the blood. Other blood tests may be used to look for possible infections.

CT scan

This test uses a combination of X-rays and computer technology to produce horizontal, or axial, images (often called slices) of the body. CT scans are more detailed than regular X-rays.


This is direct exam of the main airways of the lungs (bronchi) using a flexible tube called a bronchoscope. Bronchoscopy helps to evaluate and diagnose lung problems, check blockages, take out samples of tissue or fluid, and help remove a foreign body. Bronchoscopy may include a biopsy or bronchoalveolar lavage.

Bronchoalveolar lavage

Removing cells from the lower respiratory tract to help identify inflammation and exclude certain causes.

Lung biopsy

Removing a small piece of tissue from the lung so it can be examined under a microscope.

How are interstitial lung diseases treated?

Because there are so many causes, treatment will vary. Some interstitial lung diseases do not have a cure. Treatment is aimed at preventing more lung scarring, managing symptoms, and helping you stay active and healthy. Treatment can’t fix lung scarring that has already occurred.

Treatments may include:

  • Lung transplant
  • Oral medicine, including corticosteroids to reduce inflammation and cyclophosphamide (Cytoxan) to suppress the immune system
  • Oxygen therapy, from portable containers
  • Pulmonary rehab

Check with your healthcare provider about getting flu and pneumococcal shots. Getting a flu shot every year can help prevent both the flu and pneumonia. In addition, pneumococcal bacteria can cause minor problems, such as ear infections, but can also develop into life-threatening illnesses of the lungs (pneumonia), the covering of the brain and spinal cord (meningitis), and the blood (bacteremia). Pneumococcal disease can be acquired by anyone, but children younger than age 2, adults ages 65 and older, people with certain medical problems, and smokers are at the highest risk.  

Key points about interstitial lung diseases

  • Interstitial lung disease is the name for a group of 100 lung disorders that inflame or scar the lungs.
  • The cause is not known. Major contributing factors are smoking and inhaling environmental or occupational pollutants.
  • The most common symptoms are shortness of breath, especially with activity, and a dry, hacking cough.
  • Tests that help measure the lungs’ ability to exchange oxygen and carbon dioxide are used to diagnose the condition. Blood tests and imaging tests may also be used to see how severe the problem is and monitor it over time.
  • The goal of treatment for people with the disease is to prevent more scarring and manage symptoms.

Next steps

Tips to help you get the most from a visit to your healthcare provider:

  • Know the reason for your visit and what you want to happen.
  • Before your visit, write down questions you want answered.
  • Bring someone with you to help you ask questions and remember what your healthcare provider tells you.
  • At the visit, write down the name of a new diagnosis, and any new medicines, treatments, or tests. Also write down any new instructions your healthcare provider gives you.
  • Know why a new medicine or treatment is prescribed, and how it will help you. Also know what the side effects are.
  • Ask if your condition can be treated in other ways.
  • Know why a test or procedure is recommended and what the results could mean.
  • Know what to expect if you do not take the medicine or have the test or procedure.
  • If you have a follow-up appointment, write down the date, time, and purpose for that visit.
  • Know how you can contact your healthcare provider if you have questions.

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