Interstitial Lung Disease (ILD)

Interstitial lung disease (ILD) is a group of lung disorders characterized by fibrosis (scarring) of the airs sacs (alveoli) and the tissues around the air sacs (interstitium).

When you inhale, oxygen passes through your trachea to your lungs and into your alveoli — the smallest functional units of the lung where gas exchange occurs. The oxygen enters the blood vessels around the alveoli and carbon dioxide (a waste product) leaves the blood vessels. You exhale the carbon dioxide when you breathe out.

The interstitium are all of the tissues surrounding the alveoli and the air tubes of the lung. The tissues include blood vessels, lymphatic tissue (channels that carry excess fluid and cells of the immune system), and a variety of other cells. The interstitium is the mesh that holds all of the air tubes and air sacs together, maintaining the lungs’ overall structure.

When scarring (fibrosis) occurs in the interstitium, the air exchange is not as efficient. Fibrosis can be seen on imaging (like a CT scan or a chest x-ray) or when a piece of lung tissue is seen under a microscope by a pathologist.

Types of ILD

There are close to 200 individual entities that have been described. Our clinical team diagnosis and treats a broad range of ILDs. Some common examples include:

• Pulmonary fibrosis (PF) and idiopathic pulmonary fibrosis (IPF)
• Hypersensitivity pneumonitis
• Sarcoidosis
• Associated with autoimmune or connective tissue disease like scleroderma, lupus, rheumatoid arthritis, and Sjogren’s disease
• Associated with vasculitis like granulomatosis with polyangiitis (GPA, Wegner’s granulomatosis), eosinophilia with granulomatosis and polyangiitis (EGPA, Churg-Strauss), basement membrane deposition disease (Anti-GBM, Goodpasture’s)
• Occupational lung diseases like asbestosis, silicosis, or berylliosis
• Cystic lung diseases like lymphangiolyomyomatosis (LAM), Birt-Hogg-Dubé, or Langerhans cell histiocytosis (LCH)
• Pulmonary alveolar proteinosis
• Chronic eosinophilic pneumonia
• Bronchiolitis obliterans syndrome (BOS) after lung transplant or hematopoietic stem cell transplant (HSCT)

Our team evaluates and treats these and many other types of ILD beyond the list above.

What Causes Interstitial Lung Disease?

ILD generally begins with inflammation that leads to abnormal or dysfunctional healing and eventually causes irreversible scarring. ILD can have a multitude of causes which can be broadly divided into:

• Exposure to particles (organic and inorganic) that are inhaled
• Medications such as chemotherapy, certain antibiotics, or other drugs
• Connective tissue / autoimmune diseases such as lupus, scleroderma, rheumatoid arthritis and others
• Sarcoidosis
• Idiopathic (cause is not known)

ILD Symptoms

There are many related and unrelated symptoms of ILD, which is why a thorough history and physical taken by a specialist can be of the utmost importance. Symptoms can be mild or vague in the beginning, but progress over time and become more bothersome. The rate at which these symptoms progress and the degree to which they affect you depends on the type of ILD you have. Symptoms of ILD may include:

• Chest pain
• Clubbing (rounding) of fingers and toes
• Cough
• Fatigue
• Poor appetite and weight loss
• Shortness of breath and decline in exercise tolerance
• Weakness

Diagnosis — What You Can Expect

The diagnosis of ILD relies on invasive and non-invasive methods, starting with an extensive and thorough medical history including symptoms, exposures, medication review and physical exam. This is usually the first, and often, most important step.

Once we have a complete overview of your health, we will order lab tests, which may include:

• Arterial blood gas testing measures the acidity in your blood, including the amount of carbon dioxide (C02).
• Antibody testing checks for autoimmune diseases such as, lupus, rheumatoid arthritis, scleroderma or vasculitis (diseases that inflame blood vessels).
• Additional labs check for inflammation by checking your liver function, “inflammatory markers,” hemoglobin, electrolytes and evidence of muscle inflammation.

At our state-of-the-art pulmonary function testing lab, you may undergo testing which may include spirometry (to measure the force at which you exhale and inhale), lung volumes, diffusion capacity (measure of oxygen’s ability to cross from the air sacs into the blood vessels), or a 6-minute walk test. Additional tests may be ordered if indicated by your doctor.

We can see ILD with a plain chest X-ray. We will also need high-resolution CT scan (HRCT) as it provides superior information on the structure of the lung tissue. For ILD, we obtain HRCT images with inspiration and expiration (breath in, hold it; breath out, hold it), and also positioning on your back and on your stomach. We work very closely with our Department of Radiology; collaboration with cardiothoracic radiologists (doctors with sub-specialty training in chest imaging) helps ensure an accurate interpretation of your imaging.

Depending on the cause of your ILD, a tissue biopsy may not be necessary. If it is necessary, procedures may include:

• Bronchoscopy: A narrow, flexible tube (bronchoscope) with a light and camera is inserted through the mouth and down the trachea (windpipe) where a lavage is performed (a small amount of saline is injected into the air tubes and then sucked out) and sent to the lab for analysis. This is meant mostly to exclude infection.
• Transbronchial biopsy: Using a bronchoscope, small tissue samples (about the size of a pen tip) are obtained from the periphery of the lung and viewed under fluoroscopy (a live x-ray).
• Transbronchial cryo-biopsy: A similar technique to transbronchial biopsy, a “cryoprobe” is used to freeze the tissue at the periphery of the lung. This provides a much larger sample and can help avoid the need for a surgical lung biopsy.
• Surgical lung biopsy: When the suspected ILD requires a surgical biopsy, we partner closely with the Department of Cardiothoracic Surgery. Usually, a video-assisted thoracoscopic surgical (VATS) procedure allows a cardiothoracic surgeon to use several small incisions, sometimes robot-assisted, to obtain the smallest necessary biopsy and in the least invasive way possible.
• Envisia^® testing: Envisia genomic classifier testing is a non-invasive test we may add if a bronchoscopy is pursued. It allows us to increase the diagnostic likelihood of Idiopathic Pulmonary Fibrosis and differentiate your lung disease from other forms of ILD. This state-of-the-art test increases the likelihood of an accurate diagnosis and in many cases, decreases the need for tissue biopsy.

ILD Treatments — Medications and Therapy

Although it does not currently have a cure, ILD is treated based on the kind of lung disease you have and other co-morbidities that might exist. We tailor the therapy for your ILD based on the extent/severity of your lung disease, medical history, age, and your personal preferences for your health care. Examples of available therapies include:

• Medications
  • Corticosteroids: Oral corticosteroids (i.e. Prednisone) are the mainstay of treatment for many ILDs. They are used as mono-therapy or can be used in conjunction with other ‘steroid-sparing agents’.
  • Steroid sparing agents: These are medications that ‘tone-down’ your immune system, decreasing inflammation and scarring in the lungs. Common medications may include Azathioprine, Mycophenolate Mofetil and Methotrexate. Occasionally, in more advanced or harder to treat ILDs, we use infusions of medications like Cyclophosphamide, Rituximab or monoclonal antibodies like Infliximab. The choice of medication depends entirely on the cause of the ILD and the symptoms.
  • Anti-fibrotic medications: A class of medications that slow (or, sometimes, halt) scarring (fibrosis). These include Pirfenidone and Nintedanib. Since 2019, these medications have been approved for a much wider range of scarring conditions in the lung.
  • Investigative medications: We participate in clinical trials evaluating the use of new medications in ILD. These trials may involve repurposing previously used medications to a different ILD. Our ILD providers and research coordinators will let you know if you might qualify for an ongoing clinical trial.
• Oxygen therapy
• Pulmonary rehabilitation
• Smoking cessation
• Diagnosing and treating acid reflux (heart burn)

Expertise From Our ILD Team

The diagnosis of an ILD can be very complex and frequently requires agreement between experts from numerous specialties. We embrace a comprehensive approach to the diagnosis and management of each patient’s ILD via bi-monthly conferences attended by physicians from the pulmonary/interventional pulmonology, cardiothoracic radiology, pathology, and rheumatology departments. Each patient’s unique case is approached with care and real-time decisions are frequently made by the end of the conference. Our team can also get patients access to available clinical trials. Our ILD team is led by:

Additional specialties that are involved with the treatment of ILD includes:

• Pulmonologists with ILD focus
• Radiologists
• Cardiothoracic surgeons
• Interventional pulmonologists
• Pathologists
• Physical and occupational therapists
• Respiratory therapists
• Rheumatologists