Interstitial lung disease (ILD)


What is interstitial lung disease

Interstitial lung diseases (ILDs) are a group of diffuse parenchymal lung disorders associated with substantial morbidity and mortality. They are classified as restrictive lung diseases, meaning the lungs have trouble expanding upon exhale. There are several subsets of ILD, including but not limited to idiopathic interstitial pneumonias (IIP) such as Idiopathic Pulmonary Fibrosis, exposure-related ILD, and CTD-related interstitial lung diseases such as scleroderma, rheumatoid arthritis, and sjogren’s syndrome. World health organization group 3 includes ILD associated with pulmonary hypertension (PH).

How common is interstitial lung disease

The estimated incidence of ILD is 30 per 100,000 per year, with approximately one-third in the IPF category; the estimated incidence was slightly higher for men than women.1 Incidence of specific ILDs is dependent on the ILD itself. Idiopathic Pulmonary Fibrosis newly occurs in approximately 12 per 100,000 people per year.2

Questions regarding your interstitial lung disease therapy

You can reach the Accredo PAH care team, anytime, day or night, seven days a week by phone or online.

24-hour Customer Service Center


  • 1Coultas DB, Zumwalt RE, Black WC, Sobonya RE. Am J Respir Crit Care Med. 1994 Oct; 150(4):967-72
  • 2Ferri, Fred F. (2017). Ferri's Clinical Advisor 2018 E-Book: 5 Books in 1. Elsevier Health Sciences. p. 691. ISBN 9780323529570


What are the symptoms of interstitial lung disease

The symptoms for all types of interstitial lung diseases may be similar, and symptoms are usually more severe as the disease progresses. Symptoms of ILD may include:

  • Exertional dyspnea
  • Labored breathing
  • Dry cough
  • Chest discomfort
  • Loss of appetite
  • Weight loss (occasionally)
  • Bleeding in the lungs

As the disease state progresses, these symptoms will likely intensify in severity. Patients with pulmonary hypertension (PH) associated with an ILD may also experience:

  • Lower extremity edema
  • Difficulty breathing when lying flat
  • Pre-syncope / syncope (fainting)

Additional symptoms are possible based on specific ILD diagnosis.

How is it diagnosed

The diagnosis of interstitial lung disease is challenging as numerous disorders fall under the broad category of ILD. Signs and symptoms can be very similar across the different disorders under ILD. Additionally, other disease states can display signs and symptoms similar to ILD, therefore ruling out other disorders is essential before making a diagnosis.

Blood tests

Blood tests can detect markers of autoimmune diseases or inflammatory responses to environmental exposures that are linked to interstitial lung diseases.

Imaging tests

CT scans and Echocardiograms are imaging tests that are important in narrowing down the diagnosis of ILD and potentially the more specific ILD in which the patient should be diagnosed. The ability to show fibrosis and details behind the severity of scarring is helpful in determining the treatment regimen and medication(s) the patient should take to assist with their diagnosis.

Pulmonary function tests

These tests measure how much air your lungs can hold, how much air moves in and out of them and the lungs’ ability to exchange oxygen. These tests may be performed to potentially identify its cause. Specific pulmonary function tests include Spirometry and diffusion capacity and Oximetry.

Lung tissue analysis

Tissue samples of a patient’s lung can be helpful in determining diagnosis of interstitial lung disease. Bronchoscopy, bronchoalveolar lavage, and surgical biopsy are particular ways in which tissue samples can be collected.

High resolution computerized tomography

This imaging test is key to, and sometimes the first step in, the diagnosis of interstitial lung disease. CT scanners use a computer to combine X-ray images taken from many different angles to produce cross-sectional images of internal structures. A high-resolution CT scan can be particularly helpful in determining the extent of lung damage caused by interstitial lung disease. It can show details of the fibrosis, which can be helpful in narrowing down the diagnosis and in guiding treatment decisions.

Right-heart catheterization

If the results of initial tests point to PH-associated with a patient’s ILD, your doctor will schedule a right-heart catheterization (commonly referred to as a “right heart cath”). Right-heart catheterization is one of the most accurate and useful tests to get a definitive diagnosis for pulmonary hypertension. This is the only test that directly measures the pressure inside the pulmonary arteries, and it should be done in all patients at least once to confirm a patient’s diagnosis of pulmonary hypertension. During the test, doctors insert a catheter (a thin rubber tube) through a large vein in the patient’s groin or neck. They then pass the catheter up into the patient’s heart to measure the blood pressure in the right side of the heart and lungs.


Interstitial Lung Disease (PH-associated) Medications

While there is currently no cure for ILD-PH, different treatment options are available to help you manage your disease and feel better day-to-day depending on your type of ILD associated with PH. Your doctor may prescribe other medication(s) as part of your treatment based on your particular ILD diagnosis. The following specialty medication is available at Accredo for the treatment of ILD-PH.

Medication Manufacturer
Ofev® (nintedanib) Boehringer Ingelheim
Tyvaso® (treprostinil) United Therapeutics Corp

Financing Your Care

Financial assistance coordination may be available to help with your medication costs, including manufacturer and community programs. Accredo representatives are available to help find a program that may work for you.

Community financial resources

Financial Guidance

Life-saving specialty medication can be expensive. Learn how the Accredo teams help individuals find ways to afford the medication they need to survive in this video.

Find Support

There are many organizations that support research and advocacy for interstitial lung disease. See below for a few of those organizations.

Support organizations

Government organizations

Meet the Team

Accredo’s Interstitial lung disease (ILD) care team is dedicated to serving you and we understand the complexity of your condition. Our specialty-trained clinicians are available 24 hours a day, seven days a week, to answer any questions.

Why We Do It

Accredo supports patients with chronic and complex conditions and helps them live their best life. Watch our video to learn why we do what we do for our patients.

Why We Do It video transcript

24-hour Customer Service Center