Interstitial Lung Disease

Definition

Interstitial lung disease (ILD) is a group of disorders that lead to scarring (fibrosis) and swelling 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 get worse.

Causes

Injury or illness can cause swelling 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 extra 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 for the body.

This process may begin or go on because of:

• Lung diseases or infections
• Spending a long time around irritants, such as cigarette smoke, dust, gasses, or fumes from industry or agriculture
• Problems with the immune system
• Some medicines, such as:
  • Nonsteroidal anti-inflammatory drugs (NSAIDs)
  • Chemotherapy
  • Medicines that change or suppress the immune system
• Genetic problems

In some people, the 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 harm lung tissue

Symptoms

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

A person with ILD may also have:

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

Diagnosis

The doctor will ask about 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 the chest. This can be done with:

• Chest x-ray
• CT scan
• Echocardiogram

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

Treatment

The goal of treatment is to manage symptoms, slow the disease, and help quality of life. Lung damage cannot be reversed. How this is done depends on the cause of ILD. The doctor may advise:

• Lifestyle changes, such as not smoking
• Medicines to slow the disease, such as:
  • Corticosteroids to ease swelling
  • Medicines to suppress the immune system
• Pulmonary rehabilitation—therapy to help with shortness of breath
• Oxygen therapy to raise 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 ILD may be lowered by:

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