Interstitial Lung Disease: What is ILD?

The term interstitial lung disease (ILD) refers to a broad range of progressive lung disorders characterized by inflammation and scarring of the lungs. Interstitial lung diseases affect the interstitium, the lace-like network of tissue between and supporting the microscopic alveoli (air sacs). The interstitium is filled with tiny blood vessels that allow for gas exchange between the blood and the lungs. It is so thin that it normally can’t be seen with an X-ray or CT scan.^[1][2]

Types of ILD

There are a large number of disorders classified as ILD; some are short-lived and others are chronic (ongoing) and irreversible. Some types are listed below:

• Interstitial pneumonia – The interstitium of the lungs can be infected by bacteria, viruses, or fungi. The most common bacteria known to cause interstitial pneumonia is a bacteria called Mycoplasma pneumonae. 
• Idiopathic pulmonary fibrosis (IPF) – This type of ILD causes ongoing, progressive fibrosis (scarring) of the interstitium. The cause of idiopathic pulmonary fibrosis in unknown.
• Nonspecific interstitial pneumonitis – This condition is often present with rheumatoid arthritis, scleroderma or other autoimmune disorders.
• Hypersensitivity pneumonitis – This condition is caused by chronic inhalation of dust, mold or other airway irritants.
• Cryptogenic organizing pneumonia (COP) –Also called bronchiolitis obliterans with organizing pneumonia (BOOP), COP is a pneumonia-like interstitial lung disease that occurs in the absence of infection.
• Acute interstitial pneumonitis –A severe form of ILD that occurs suddenly and often requires emergency life support.
• Desquamative interstitial pneumonitis –Often difficult to diagnose, this type of ILD is partially caused by long-term smoking.
• Sarcoidosis –A disease that leads to ILD and is accompanied by swollen lymph nodes. Also sometimes involves the heart, skin, nerve or
• Asbestosis –A type of ILD caused by exposure to asbestosis.

Symptoms of Interstitial Lung Disease

Shortness of breath upon exertion and a dry, unproductive cough are the most common symptoms of ILD. Other symptoms that may help identify the disease include mucus production, hemoptysis (blood in the mucus) and wheezing. Patients with prominent, non-respiratory symptoms such as muscle pain, joint pain or thickening and tightness of the skin, fingers and toes may have interstitial lung disease caused by an underlying connective tissue disorder.^[3]

Treatment of Interstitial Lung Disease

Treatment of ILD depends upon the severity of the illness and the underlying cause. It may include the following:

Medication management

The goal of medication therapy is to improve breathlessness, reduce inflammation and suppress an over-active immune system. Common medications used to treat ILD are as follows:^[4]

• Oral steroids – May decrease lung inflammation and improve symptoms.
• Mycophenolate – May be used to reduce the amount of steroids required. Prevents the immune system from attacking cells in the body that cause fibrosis.
• Azathioprine – Another drug that may be used to reduce the amount of steroids required.
• Cyclophosphamide – Used if steroid treatment is ineffective or not possible.
• Pirfenidone – Has anti-inflammatory and anti-fibrotic properties that may help slow disease progression for some people with IPF.
• Nintendanib – Blocks pathways that may lead to fibrosis and slows disease progression in some people with IPF.

Oxygen therapy

Because many people with ILD have low levels of oxygen in their blood, oxygen therapy improves blood oxygen levels while reducing strain on the heart and lungs and improving breathlessness and fatigue.^[5]

Pulmonary rehabilitation

A formal program designed to improve fitness in people with breathing problems. Includes exercise training, breathing techniques, nutritional counseling, education, support and more.⁵

Lung transplant

May be an option for some patients with advanced disease when standard medical treatment has failed. May improve quality of life and increase survival in a select group of patients who meet very strict criteria.⁵

For more information on interstitial lung disease, talk to your primary care provider.

 _{[1] WebMD. Interstitial Lung Disease. Medically reviewed 7/31/2016.}

_{[2] Mayo Clinic. Interstitial Lung Disease. Updated 6/11/2015.}

_{[3] Chapman, Jeffrey T. Interstitial Lung Disease. Cleveland Clinic. August, 2010.}

_{[4] National Jewish Health. ILD Medications. Last reviewed December, 2014.}

_{[5] National Jewish Health. ILD Treatment. Last reviewed December, 2014.}