What is Interstitial Lung Disease?

Interstitial lung disease (ILD) is a group of lung conditions that cause breathing difficulties. Symptoms include fatigue, shortness of breath, and a persistent cough. ILD can be caused by infection, exposure to certain chemicals or drugs, autoimmune disease, and smoking. Treatment typically involves a combination of medications, oxygen therapy, and lifestyle changes.

Types of Interstitial Lung Disease

There are many different types of interstitial lung disease. The types differ by severity, cause, symptoms, and length of the condition.

Types of Interstitial lung disease include:

• Sarcoidosis—This form of interstitial lung disease is marked by swollen lymph nodes. Sarcoidosis can cause inflammation and damage to your lungs, eyes, heart, and skin.
• Acute interstitial pneumonitis—This is a sudden and severe form of interstitial lung disease. Individuals with this condition usually require mechanical ventilation to breathe.
• Cryptogenic organizing pneumonia (COP)—COP is a lung disease that is similar to pneumonia, but it is not caused by an infection. Doctors also refer to COP as bronchiolitis obliterans with organizing pneumonia.
• Interstitial pneumonia—The interstitial space may become infested with germs, viruses, or fungi. The most prevalent microorganism responsible for this condition is called Mycoplasma pneumoniae.
• Idiopathic pulmonary fibrosis—This form of interstitial lung disease is marked by an accumulation of scar tissue in the lungs.
• Familial pulmonary fibrosis—This is a respiratory illness that affects more than one person in the same family.
• Asbestosis—This condition develops from exposure to asbestos fibers. These fibers can become lodged in your lungs and cause scarring and swelling. 
• Nonspecific interstitial pneumonitis—This is a catch-all term used to describe interstitial lung diseases correlated to autoimmune diseases.
• Desquamative interstitial pneumonitis—This form of interstitial lung disease is partially caused by smoking.
• Coal worker’s pneumoconiosis—This is an illness caused by breathing in coal dust. It is also known as black lung disease.
• Hypersensitivity pneumonitis—This is a reaction to prolonged exposure to airborne particles, such as dust, animal dander, mold spores, or chemicals.

Signs & Symptoms

Interstitial lung disease damages the tissues and spaces between the air sacs in your lungs, causing multiple symptoms of varying intensity. There are moderate and severe interstitial lung disease symptoms.

Common symptoms of interstitial lung disease:

• Shortness of breath
• A dry, hacking cough
• Fatigue
• Chest discomfort
• Weight loss
• Weakness
• Heavy breathing

Moderate Symptoms

Moderate symptoms of the condition might be coughing, fatigue, and shortness of breath. Left untreated, the condition usually progresses to more severe symptoms. These symptoms occur in mild interstitial lung disease.

Severe Symptoms

Symptoms of severe interstitial lung disease include chest pain, extreme fatigue, and bleeding in your lungs. We recommend that you seek emergency treatment immediately if you experience any of these severe symptoms.

Causes

Doctors do not know the exact cause of most interstitial lung disease. Damaged lungs cause an unusual healing response. This abnormal healing leads to thick and scarred tissues between your air sacs. The resulting respiratory condition is sometimes worse than the original injury. 

The most common causes of interstitial lung disease are occupational and environmental factors, medications, and medical conditions.

Occupational and Environmental Factors

Prolonged exposure to certain airborne particles, such as asbestos and metalworking chemicals, can damage your lungs.

Inhalation of certain chemicals used in farming, manufacturing, or home renovation can also lead to the development of this condition.

Medications

Any drug that harms your lungs can cause interstitial lung disease. These drugs include certain antibiotics, heart medications, anti-inflammatory drugs, and cancer treatments. The risk of developing this condition is higher if you are taking multiple drugs that harm your lungs.

Medical Conditions

Autoimmune disorders can lead to lung damage, which can develop into interstitial lung disease. These disorders cause your immune system to attack your body's own tissues. Interstitial lung disease can also be a complication of other lung diseases, such as pulmonary fibrosis, sarcoidosis, and tuberculosis.

Risk Factors

Risk factors for interstitial lung disease revolve around your environment, age, and lifestyle.

Common interstitial lung disease risk factors:

• Exposure to irritants—If you regularly breathe irritants, pollutants, and chemicals, you have a higher risk of getting interstitial lung disease.
• Age—Anyone of any age can develop the condition but it is more common in adults.
• Cancer treatments—Exposure to radiation and chemotherapy increases your risk of interstitial lung disease.
• Smoking—Smokers are more likely to develop interstitial lung disease than nonsmokers.
• Genetics—A family history of interstitial lung disease or autoimmune disorders places you at higher risk.
• Autoimmune diseases—If you have an autoimmune disease, such as rheumatoid arthritis, you’re at a greater risk of developing interstitial lung disease.
• Gastroesophageal reflux disease—Untreated acid reflux can lead to interstitial lung disease.

Diagnosis

Your doctor will make an interstitial lung disease diagnosis after a routine medical examination and a customized combination of tests.

Lab Tests

Blood tests can be helpful in diagnosing interstitial lung disease. Your doctor may perform blood tests to rule out autoimmune disorders.

Blood tests usually involve:

• Blood samples
• Checking for antibodies
• Oxygen level examination
• Carbon dioxide analysis

Imaging Tests

Your doctor may order imaging tests to inspect your lungs for damage.

Imaging tests might include:

• X-rays
• Computed tomography (CT) 

Pulmonary Function Tests

Pulmonary function tests evaluate your lungs performance on several metrics.

Tests might include:

• Forced vital capacity
• Forced expiratory volume
• Vital capacity
• Total lung capacity
• Tidal volume

Lung Tissue Analysis

A lung biopsy is the most definitive way to diagnose interstitial lung disease. During a lung biopsy, your doctor will remove a small sample of lung tissue for testing.

Lung biopsy procedures include:

• Thoracoscopy—A surgical procedure in which a Thoracoscope—a long, thin tube with a light and camera—is inserted through an incision in your chest.
• Bronchoscopy—A minimally invasive procedure in which a bronchoscope—a thin tube with a sample-collecting apparatus attached to one end—is inserted through your mouth or nose.
• Needle biopsy—In this procedure, a needle is inserted through your chest wall to remove a sample of lung tissue.

Treatment

Interstitial lung disease treatment focuses on relieving symptoms and preventing the progression of the disease. Treatment options include oxygen therapy, inflammation control, antibiotics, lung transplant, and immune suppression.

Oxygen Therapy

Inhaled oxygen is a common treatment for interstitial lung disease. Oxygen therapy can help to relieve symptoms and prevent complications. If you have interstitial lung disease, your doctor may prescribe regular oxygen therapy. Oxygen therapy involves inhaling oxygen through a mask or nasal cannula. The oxygen is typically delivered at a higher concentration than the air we breathe.

Inflammation Control

Interstitial lung disease is often caused by inflammation in the lungs. Inflammation control is a key part of treatment. Treatment options include corticosteroids, immunosuppressants, and biologics. Anti-inflammatory medications can usually be taken orally.

Antibiotics

Antibiotics may be used to treat interstitial lung disease that is caused by an infection. Antibiotics can resolve infections and reduce inflammation. You can also use antibiotics to treat fungal infections that may cause interstitial lung disease. You might take antibiotics temporarily or long term.

Immune Suppression

Certain medications can slow down your immune system. Suppressing your immune system can help reduce inflammation and prevent the progression of interstitial lung disease. Immune suppression medication might not directly treat your condition. Instead, it may help to prevent the disease from getting worse.

Lung Transplant

If your interstitial lung disease is severe, your doctor may recommend a complete lung transplant. A lung transplant is a major surgery. It is usually only recommended for people who have an interstitial lung disease that is not responding to other treatment options. After a lung transplant, many people report a higher quality of life.

Complications

The main Interstitial lung disease complications are respiratory failure, high blood pressure, and right-sided heart failure. These complications can be severe and potentially life-threatening.

Complications:

• Respiratory failure—Your lungs can't send enough oxygen into your blood. Over time, this can cause heart failure.
• High blood pressure—The blood vessels in your lungs become restricted. This makes it difficult for your heart to properly pump blood.
• Right-sided heart failure—This can happen when the right side of your heart is forced to work harder than normal. The added stress might lead to heart failure.

Prevention

You can take several steps to prevent many causes of interstitial lung disease. There is no way to prevent the genetic form of the condition.

Possible prevention methods:

• Stop smoking
• Wear respirators
• Exercise regularly
• Get vaccinated
• Treat acid reflux
• Treat autoimmune disorders
• Avoid airborne irritants