Causes and Symptoms of Interstitial Lung Disease (ILD)

What is interstitial lung disease?

Interstitial lung disease (ILD) is the name for more than 200 lung disorders that affect the interstitium, the tissue and space around the alveoli (air sacs). The interstitium is the tiny, fluid-filled tissue and space around the air sacs in the lungs.

In healthy people, the interstitium is very thin. In interstitial lung diseases, the interstitium thickens and scars. Over time, the scarring can cause lung stiffness and eventually affect breathing.

People with interstitial lung disease find it hard to get enough oxygen into their bloodstream. If you have an interstitial lung disease, other compartments of your lungs can also be affected, including:

• Alveoli
• Airways (trachea, bronchi, and bronchioles)
• Blood vessels
• Pleura (outside lining of the lung).

• Asbestosis: is an interstitial lung disease caused by asbestos exposure
• Idiopathic pulmonary fibrosis: chronic, progressive scarring of the interstitium (idiopathic means that the cause is unknown)
• Interstitial pneumonia: bacteria, viruses, or fungi infect the interstitium
• Nonspecific interstitial pneumonitis is an interstitial lung disease that often occurs with autoimmune conditions such as rheumatoid arthritis or scleroderma
• Sarcoidosis: abnormal nodules, called sarcoid granulomas, appear in the body’s tissues.

While some forms of interstitial lung disease are short-lived, others can be chronic and irreversible.

What are the causes of interstitial lung disease?

There are many different substances, conditions and triggers that can lead to interstitial lung disease, such as:

• Drugs – certain chemotherapy drugs, heart medications, antibiotics and anti-inflammatories can damage the lungs
• Infections – bacteria, viruses, or fungi can infect the interstitium
• Regular exposures to inhaled irritants – asbestos, silica dust, talc, coal, metal dust and grain dust can cause some forms of interstitial lung disease
• Unknown causes (Idiopathic) – the causes of most interstitial lung diseases have not yet been identified.

Interstitial lung disease is more common in people with autoimmune disease, including lupus, rheumatoid arthritis and scleroderma. However, men and women of any age can develop interstitial lung disease.

What are the signs and symptoms of interstitial lung disease?

The most common symptom of interstitial lung disease is shortness of breath which develops slowly, over several months. Other symptoms include a dry, scratchy cough and weight loss.

Rarely, acute interstitial pneumonitis can occur rapidly with the onset of symptoms over hours or days.

What are the possible tests to detect interstitial lung disease?

There are many tests to look for specific signs of interstitial lung disease and rule out other forms of lung disease. If your doctor thinks you have interstitial lung disease, you may need one or more of the following tests:

• Blood tests – to identify specific causes of interstitial lung disease
• Chest X-ray – images in people with interstitial lung disease may show fine lines in the lungs
• CT scan – will identify if interstitial lung disease is present and help differentiate between different types of disease
• Lung biopsy – a small amount of lung tissue may be required to identify the type of lung disease
• Oximetry – a test measuring the oxygen saturation in your blood
• Spirometry – a lung function test measuring how much air your lungs can hold and how quickly you can move air out of your lungs.

All people with interstitial lung disease should have their case discussed by interstitial lung disease experts at a multi-disciplinary team meeting (MDT). This process will ensure all appropriate tests have been performed to enable an evidenced-based diagnosis and expert management plan.

St Vincent’s Hospital has a fortnightly MDT where patient cases are discussed. Your referring respiratory physician and GP will be provided with a report.

What are the possible procedures and treatments for interstitial lung disease?

Treatment for interstitial lung disease depends on the type of disease you have. Your treatment plan may include:

• Antibiotics – medicines that fight bacterial infections
• Antifibrotics – medications that can slow the disease progression in idiopathic pulmonary fibrosis
• Bronchodilators – inhaled medicines that help to open up your airways. If you are prescribed an inhaler (or puffer), it’s important to use it correctly so that your lungs can benefit from the medication. Read through the National Asthma Council of Australia’s Inhaler Checklist to see if you are using your puffer correctly.
• Immunosuppression – medicines that reduce inflammation and swelling in your airways
• Oxygen therapy – oxygen can help to reduce shortness of breath, protect your organs and enhance your quality of life
• Pulmonary rehabilitation – in a rehabilitation service, a team of health professionals can teach you about how to manage your interstitial lung disease and monitor your condition, covering exercise, disease management, and counselling to help you stay as healthy and active as possible; this can improve symptoms of breathlessness and exercise capacity
• Surgery – in severe cases, your doctor may suggest surgery to remove diseased lung tissue or replace a diseased lung with a healthy one (lung transplant).

What is the future plan if you have interstitial lung disease?

Interstitial lung disease can be a progressive disease, meaning it may worsen gradually over time. Some types of interstitial lung disease can’t be cured or reversed. However, your doctor will give you a treatment plan that will help to improve your symptoms, slow the progress of the disease and maintain your quality of life if this is the case.

It’s important to see your doctor regularly so your treatment plan can be adapted to suit any changes in your condition. Research into causes and treatments of interstitial lung disease is ongoing. Talk to your doctor about clinical studies and experimental treatments in this area.