Interstitial lung disease is the name for a group of more than 200 lung disorders. Most of them are long-lasting, or chronic. These diseases inflame or scar the lungs. The inflammation and scarring make it hard to get enough oxygen. The scarring is called pulmonary fibrosis.

Fibrosis leads to long-term (permanent) loss of your lung tissue's ability to carry oxygen. When the scar tissue forms, it destroys the air sacs. It also destroys the lung tissue around the air sacs and the lung capillaries.

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 often start with inflammation in the interstitium. The interstitium is the supporting structure of the lungs. It's almost like a scaffolding. This inflammation then causes inflammation in other parts of the lung, leading to conditions, such as:

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

Interstitial lung disease has been linked to certain diseases, such as sarcoidosis or rheumatoid arthritis. It can also be caused by factors in the environment. Often, its cause is not known.

Major contributing factors are smoking and inhaling environmental or occupational pollutants, such as inorganic or organic dusts.

Other factors include:

• Certain illegal drugs or medicines
• Certain connective tissue or collagen diseases
• Family history
• Radiation treatment

Symptoms are a bit different for each person. The disease may run a slow or rapid course. People with the disease may have symptoms that range 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 gets thick and becomes stiff. Breathing becomes more difficult.

Here are the most common symptoms:

• Shortness of breath, especially with activity
• Dry, hacking cough that does not produce phlegm
• Extreme tiredness and weakness
• No appetite
• Unexplained weight loss
• Mild pain in the chest
• Labored breathing, which may be fast and shallow
• Bleeding in the lungs

These symptoms may look like other lung conditions or health problems. Talk with your doctor for a diagnosis.

A doctor will ask about your health history and do a physical exam. You may also need pulmonary function tests. These tests help to measure the lungs' ability to move air into and out of the lungs. The tests are often done with machines into which you breathe. They may include the following:

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 if the lung disease is restrictive. This is when the lungs get stiff and can't hold as much air. Or if the lung disease is obstructive. This is when airflow is disrupted in the airways.

This device is used to measure 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.

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

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 or other diseases that may cause interstitial lung disease.

This test uses a combination of X-rays and a computer to make images of the body. CT scans are more detailed than regular X-rays.

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

This test removes cells from the lower respiratory tract to help find inflammation and rule out certain causes.

This test removes a small piece of tissue from the lung so it can be checked under a microscope.

Because there are so many causes, treatment will vary. Some interstitial lung diseases don't 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
• Medicine taken by mouth (oral), including corticosteroids to reduce inflammation, medicines that suppress the immune system (such as cyclophosphamide, methotrexate, mycophenolate mofetil, and others), or both. Some medicines protect the lung from more damage and scarring. These are called antifibrotics and include nintedanib and pirfenidone.
• Oxygen therapy, from portable containers
• Pulmonary rehab

If you smoke or use vaping devices, ask your doctor for help to stop. Also check with your doctor about getting the COVID-19, 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 they can also develop into life-threatening illnesses of the lungs (pneumonia), the covering of the brain and spinal cord (meningitis), and the blood (bacteremia). Anyone can get pneumococcal disease. But those at highest risk include children younger than age 2, adults ages 65 and older, people with certain health problems, and smokers.

Talk with your doctor about the pneumococcal vaccine. The CDC recommends it for all children younger than 2 years old, all adults age 65 or older, people with certain health problems, and smokers.

• Interstitial lung disease is the name for a group of more than 200 lung disorders that inflame or scar the lungs.
• The cause is often 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.
• X-rays and other imaging studies are used to diagnose the condition. So are tests that help measure the lungs' ability to exchange oxygen and carbon dioxide.
• The goal of treatment is to prevent more scarring, manage symptoms, and help you stay active and healthy.
• If you smoke, quitting is critical to help maintain as much lung health as possible.
• Ask your doctor about getting the COVID-19, flu, and pneumococcal vaccines.

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

• 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 doctor 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 doctor 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 doctor if you have questions, especially after office hours and on weekends and holidays.