Definition

Interstitial lung disease (ILD) is a group of disorders that lead to scarring (fibrosis) and inflammation in the lung tissue. It affects the space around the small air sacs of the lung. Other parts of the lungs may be affected as these diseases worsen.

Causes

Injury or illness can cause inflammation in the lungs and airways. This stimulates a process to rebuild injured tissue. This process does not stop in people with ILD. Over time, the excess tissue that is built leads to fibrosis in the lungs. This makes it hard for oxygen to pass from the lung tissue to the blood vessels in the lungs. This decreases the amount of oxygen available to the body.

This process may begin or go unchecked because of:

• Lung diseases or infections
• Long-term exposure to irritants, such as cigarette smoke, dust, gasses, or fumes from industry or agriculture
• Problems with the immune system
• Certain medicines, such as:
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Chemotherapy
  • Medicines that change or suppress the immune system
• Genetic problems

In some people, the exact cause of the abnormal tissue building process is not known.

Normal Gas Exchange in the Lungs

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Risk Factors

This problem is more common in older adults. Other things that may raise the risk are:

• Having a lung disease that causes fibrosis, such as idiopathic pulmonary fibrosis
• Having problems with the immune system, such as rheumatoid arthritis or scleroderma
• Working in places where dust, fibers, fumes, or bird droppings may be inhaled
• Smoking
• Having other family members with this problem
• Long-term medicine use
• Cancer treatment—radiation and chemotherapy can damage lung tissue

Symptoms

The main problem is shortness of breath that worsens with time. Breathing problems happen with activity and when at rest.

Other problems may be:

• A lasting, dry cough that cannot be controlled
• Lack of energy
• Nails that bulge or thicken

Diagnosis

The doctor will ask about your symptoms and health history. A physical exam will be done. This may be enough to suspect the diagnosis.

Blood and urine tests will be done.

Images may be taken of your chest. This can be done with:

• Chest x-ray
• CT scan
• Echocardiogram

A sample of lung tissue may be taken to confirm the diagnosis. This can be done with a biopsy.

Treatment

Treatment depends on the cause of ILD. Lung damage cannot be reversed. The goal of treatment is to manage symptoms, slow the disease, and improve quality of life. Choices are:

• Lifestyle changes, such as not smoking
• Medicines to slow the disease, such as:
  • Corticosteroids to ease inflammation
  • Medicines to suppress the immune system
• Pulmonary rehabilitation to manage shortness of breath
• Oxygen therapy to increase the amount of oxygen in the lungs

People with severe symptoms and those who are not helped by these methods may need a lung transplant.

Prevention

The risk of this problem may be lowered by:

• Not smoking
• Not inhaling things that may irritate the lungs
• Wearing proper safety equipment to protect the lungs from irritants