Interstitial Lung Disease
What is interstitial lung disease?
Interstitial lung disease (ILD) is another term for pulmonary fibrosis, which means “scarring” and “inflammation” of the interstitium (the tissue that surrounds the lung’s air sacs, blood vessels and airways). This scarring makes the lung tissue stiff, which can make breathing difficult. ILD may be limited to the lung, or it can be related to a condition that may affect other parts of the body, such as rheumatoid arthritis or sarcoidosis.
These illnesses share similar features, including a nonproductive (dry) cough and shortness of breath. Although they may look similar radiographically (on chest X-ray or chest CT scan), ILDs from different causes and conditions have different treatments and outlooks. ILD is more common in adults, but can rarely occur occurs in children.
Symptoms and Causes
What causes interstitial lung disease?
There are more than 200 causes of ILD. Because ILD includes many disorders, it is categorized based on the cause. These types of ILD include:
- ILD related to another health disorder: Some people develop ILD as a result of having an autoimmune disease (the immune system harms the body). Examples of autoimmune diseases include rheumatoid arthritis, scleroderma, polymyositis/dermatomyositis, lupus and sarcoidosis.
- ILD caused by breathing in harmful substances: People who breathe harmful particles such as coal dust, asbestos, tobacco smoke or hairdressing chemicals may develop ILD.
- Genetic ILD: A genetic ILD occurs when the disease is passed down among family members. These conditions include neurofibromatosis (a disease in which tumors grow on nerves) and Gaucher disease (marked by enlargement of internal organs, including the spleen and liver, and lesions on the bones).
- Idiopathic ILD: Idiopathic means the cause is not known. Idiopathic ILD usually affects people over 60 years old.
What are the symptoms of interstitial lung disease?
Most people with ILD have symptoms that make breathing difficult, including:
- Shortness of breath
- Coughing, typically nonproductive
- Decreased exercise tolerance
- Weight loss
Diagnosis and Tests
How is interstitial lung disease diagnosed?
Because there are many types of ILD, doctors use many methods to diagnose it, including the following:
- A physical exam. The doctor will also ask if you have any systemic conditions (disorders that affect the entire body) or have had any exposure to harmful substances.
- A lung function test to check how well your lungs are working
- Imaging tests such as X-ray and a high-resolution computed tomography (CT scan)
- Bronchoscopy, a test in which the doctor inserts a device called a bronchoscope through your nose or mouth into your lungs to look inside your airways.
- In some cases, a doctor will take a sample of lung tissue. A test of this tissue, called a biopsy, can further identify the type of ILD. During a biopsy, your doctor removes a small sample of tissue from the lung and studies it under a microscope to help identify the type of ILD.
Management and Treatment
How is interstitial lung disease treated?
Treatment for ILD is designed to preserve the lung’s ability to function and keep the disease from getting worse. Treatment depends on many factors, including the type of ILD and how severe it is, and includes:
- Medications can help improve lung function by reducing inflammation and/or fibrosis. Medications to reduce inflammation include steroids (prednisone) and other rheumatologic drugs, including mycophenolate (CellCept), azathioprine (Imuran), leflunomide (Arava), rituximab (Rituxan), cyclophosphamide (Cytoxan), tacrolimus (Prograf) and others. Medications to stop further fibrosis include pirfenidone (Esbriet) and nintedanib (Ofev).
- Oxygen therapy: Extra oxygen delivered through a tube in the nose can make breathing easier. This therapy raises the blood’s oxygen levels, so that every breath is more productive.
- Pulmonary and exercise therapy: Breathing exercises and increased physical activity can improve lung fitness.
- Lung transplant: Some people with severe cases of ILD have lung transplants to help prolong their lives.
What are the complications of interstitial lung disease?
Many people with ILD have trouble breathing and a cough that does not go away. In more severe cases, complications can be life-threatening and include high blood pressure in the lungs, right heart failure, and respiratory failure (the lungs do not deliver enough oxygen to the body).
Can interstitial lung disease be prevented?
There is no way to prevent idiopathic or genetic ILD, but it is possible to prevent some of the types with known causes. You can reduce your risk by:
Outlook / Prognosis
What is the prognosis (outlook) for people with interstitial lung disease?
There is no cure for ILD. Once scarring happens in the lungs, it usually cannot be reversed. Treatment can help slow the disease down to preserve as much quality of life as possible.
The prognosis for patients depends on how severe the condition is, and the cause of the ILD. Many people with mild ILD can function normally throughout their lives without treatment. Their condition can be stable (doesn’t get worse).
For people with more severe cases of ILD, the disease can be progressive (gets worse over time). These people may need regular treatments and therapy for the rest of their lives to help manage their symptoms.