Interstitial lung disease

When you breathe, air travels in and out of your lungs through the windpipe, airways, and branching airways. Oxygen passes from the air sacs in the lungs to the blood vessels through lung tissue called interstitium. When the lung tissue becomes inflamed and scarred around the air sacs, the changes make it hard to take in oxygen. The result is interstitial lung disease.

Interstitial lung disease includes many lung conditions

Interstitial lung disease, or ILD, is an umbrella term for a group of conditions that cause inflammation and scarring (fibrosis) around the tiny air sacs in the lungs. The changes cause stiffness in the lung tissue and make it hard to breathe and take in oxygen.

ILD can worsen if left untreated

Lung damage from diffuse lung disease can affect anyone, including children. Often it is irreversible and worsens over time if left untreated. However, ILD is not contagious, meaning it cannot be passed to another person.

What are the symptoms of interstitial lung disease?

Hiker on edge of cliff

The most common symptom of ILD is shortness of breath and difficulty breathing. Additional symptoms may include:

  • Chest discomfort and tightening.
  • Dry (nonproductive) cough.
  • Fatigue.
  • Occasional weight loss.

In most cases when symptoms present, the lung damage is already severe enough to require immediate medical treatment, as it can easily develop into life-threatening complications.

Always be sure to see your doctor at the first sign of breathing problems, or if you are experiencing any severe symptoms, to get a proper diagnosis or to rule out any other conditions.

What are the different types of ILD?

All types of ILD have thickened interstitium from inflammation, scarring, or even fluid build up. Some types are acute, meaning they only last a short time, while others are chronic, meaning they last long-term and do not go away.

Some examples of ILD include:

  • Acute interstitial pneumonitis, a sudden and severe lung disorder that requires a ventilator.
  • Asbestosis, caused by breathing asbestos.
  • Cryptogenic organizing pneumonia (COP), which is a pneumonia-like ILD that doesn’t come from infection.
  • Desquamative interstitial pneumonia, an ILD partially resulting from smoking.
  • Hypersensitivity pneumonitis, when dust, mold, or other irritants are passed through the lungs over time.
  • Idiopathic interstitial pneumonia, which is a diffuse interstitial lung disease of unknown cause.
  • Idiopathic pulmonary fibrosis, when scar tissue grows excessively in the lung tissue. This is a type of idiopathic ILD, meaning the cause is unknown, and is the most common type of ILD.

  • Interstitial pneumonitis, when the interstitium is infected by bacteria, viruses, or fungi.
  • Nonspecific interstitial pneumonia, which affects people with autoimmune conditions.
  • Sarcoidosis, which causes ILD. Sarcoidosis can also affect your eyes, nerves, skin, and heart.

physical therapy and rehabilitation

What causes ILD?

In many cases of interstitial lung disease, the cause is hard to determine. It is often the result of an injury to the lungs that triggers an abnormal healing response. With interstitial lung disease, the repair process goes wrong so that the alveoli become too scarred and thickened.

Some known causes include:

Autoimmune diseases

  • Dermatomyositis.
  • Rheumatoid arthritis.
  • Sarcoidosis.
  • Sjogren’s Syndrome.

Connective tissue diseases

  • Lupus.
  • Scleroderma (systemic sclerosis).

Medications

  • Antibiotics, including nitrofurantoin and ethambutol.
  • Anti-inflammatory drugs including rituximab or sulfasalazine.
  • Chemotherapy drugs, such as methotrexate and cyclophosphamide.
  • Heart medications that treat irregular heartbeat, such as amiodarone or propranolol.

Occupational and environmental factors

  • Animal droppings.
  • Asbestos, linked to asbestosis.
  • Coal dust.
  • Fumes.
  • Gases.
  • Grain dust.
  • Poisons.
  • Radiation exposure.
  • Silica dust, linked to hypersensitivity pneumonitis.

Other risk factors

  • Certain lung infections.
  • Genetics, when an ILD is passed down among family members. These genetic conditions include neurofibromatosis and Gaucher disease.
  • Older age, although infants and children can develop fibrotic ILD.
  • Smoking, which can not only cause ILD but also make it much worse.

Diagnosing ILD

To determine whether you have interstitial lung disease, your provider will start by going through your symptoms, health history, and doing a general physical.

Noninvasive tests

Your doctor may also order additional non-invasive tests, which may include:

  • Blood tests. Samples of your blood will be taken and inspected for proteins, antibodies, markers of autoimmune diseases, or inflammatory responses to environmental exposure like mold.
  • Chest X-ray. An X-ray is a safe and non-invasive test that uses a small amount of radiation to create images of your chest. An X-ray is the first step in ILD diagnosis to get a better look at your lungs.
  • CT scan. This diagnostic test uses computerized views to create 2-dimensional, cross-sectioned images of different angles of your body. It is used to get a better look at your lungs, usually if something abnormal has been found on an X-ray, and can help evaluate if you may have pneumonia, lung cancer, blood clots, or lung scarring or damage from smoking.
  • Echocardiogram. Using sound waves like those of an ultrasound, your doctor can create images of your heart structure and to evaluate how it is functioning. An echocardiogram is mainly used to see if you have pressure on the right side of your heart, which may indicate pulmonary hypertension.
  • Pulmonary function tests.
    • Spirometry: You are asked to breathe quickly and forcefully through a tube to measure your total lung capacity, which may have worsened from ILD.
    • Oximetry: Uses a small device on your fingers to measure the oxygen saturation in your blood.

Minimally-invasive tests

To find out what type of interstitial lung disease you have, your doctor may suggest the following, more invasive procedures:

  • Bronchoscopy. This diagnostic technique uses a small camera on a flexible tube to examine your air passages. The doctor can also use this tool to collect tissue samples from your lungs (a biopsy) that can be examined in a lab.
  • Bronchoalveolar lavage. Your doctor injects a tablespoon of saline solution through a bronchoscope into part of your lung, then sucks it back. What is pulled out contains cells from your air sacs to see if you may have any lung condition.
  • Surgical lung biopsy. If your X-ray or CAT scan has flagged any lung nodules (abnormal areas on the lungs), further analysis may be needed with a biopsy. In a biopsy of the lung, tissue within the abnormal area is extracted from the patient and examined in a lab to determine if it is cancerous. During a lung biopsy, an imaging specialist (radiologist) uses a CT scan to guide a needle through the wall of the chest and to the area of the nodule to extract the tissue.

Laboratory technician analyzing samples

Treating interstitial lung disease

Your ILD treatment will vary depending on what type you have been diagnosed with and how severe it is. Damage to the lungs from ILD is irreversible, so treatment usually begins with relieving your symptoms, improving your quality of life, and then slowing the progression of your disease.

Treatment options may include:

Lifestyle changes

  • Eat well. Losing weight is often a side effect of many types of ILD, often because eating is uncomfortable or it takes extra energy. If you’ve been diagnosed with ILD, it’s important to eat a nutritionally rich diet with adequate calories. The dieticians at UCHealth can help you manage your diet and practice healthy eating habits.
  • Getting vaccinations can help prevent respiratory infections. Make sure to get a pneumonia vaccine and annual flu shot if you have been diagnosed with ILD.
  • Stopping smoking is the best thing you can do if you have ILD. UCHealth offers smoking cessation programs to help you quit. It is also beneficial to stop being around smokers, since secondhand smoke is also harmful to your lungs.

Man eating salad

Medication

  • Corticosteroids (Prednisone). These are strong medications that decrease inflammation in your lungs. Depending on the type of interstitial lung disease you have, they may be paired with immuno-suppressant drugs. However, long-term use of corticosteroids can have negative side effects.
  • Pirfenidone and Nintedanib medications can be used to slow the progression of idiopathic pulmonary fibrosis, but come with many side effects that a patient should thoroughly discuss with a doctor.
  • GERD therapies that reduce stomach acid may help relieve symptoms associated with gastroesophageal reflux disease (GERD), which affects many patients with idiopathic pulmonary fibrosis.

Therapy

  • Oxygen therapy is a common treatment of many interstitial lung diseases, delivering extra oxygen to help make breathing easier. Oxygen therapy can also decrease complications from ILD that may lead to heart failure. They can also help improve your sleep and overall well-being
  • Pulmonary rehabilitation can help improve your daily life. Working with a respiratory therapist, you will learn breathing exercise techniques to improve your lung function, endurance, and in some instances a social worker may help with emotional support.

Lung transplant

Lung transplantation by a thoracic surgeon may be needed for the most extreme cases of ILD, often as a last result.

Frequently asked questions (FAQs) about ILD

Yes. If left untreated, interstitial lung disease can cause life-threatening complications, including:

  • Pulmonary hypertension. High blood pressure that affects the arteries in your lungs
  • Right-sided heart failure (cor pulmonale). When the heart’s right ventricle (the lower right chamber) pumps harder than usual to move blood through obstructed arteries, it can sometimes fail from the extra strain. This is usually a complication of pulmonary hypertension.
  • Respiratory failure. This is the end stage of chronic ILD, when severely low oxygen and rising arterial pressure causes heart failure.

There is no cure for ILD, as the scarring of the lungs cannot be reversed. Treatment can slow the spread of the disease and improve your quality of life.

If you have mild interstitial lung disease, you can often function normally without treatment without your condition worsening.

If you have a more severe case of ILD, it can worsen over time, and may require regular treatment of therapy for symptom relief.

The average survival for people with ILD can range from 3 to 5 years or longer with treatment. Idiopathic ILD can be fatal due to poor diagnosis and limited knowledge of the cause. Those with mild ILD can often live much longer.

It isn’t possible to prevent idiopathic or genetic ILD, but some known types can be prevented if the cause is identified.

You can reduce your risk of getting interstitial lung disease by the following practices:

  • Getting vaccinated against the flu or pneumonia.
  • Quitting smoking.
  • Wearing a respirator mask around harmful substances.