Diffuse interstitial lung disease

Answer 1

Definition

Diffuse interstitial lung disease refers to a group of lung disorders in which the deep lung tissues become inflamed.

Alternative Names

Diffuse parenchymal lung disease; Alveolitis; Cryptogenic fibrosing alveolitis (CFA); Idiopathic pulmonary pneumonitis (IPP)

Causes, incidence, and risk factors

The lungs contain tiny air sacs (alveoli), which is where oxygen is absorbed. These air sacs open up or expand with each breath.

The tissue around these air sacs is called the interstitium. In people with interstitial lung disease, this tissue becomes stiff or scarred, and the air sacs are not able to expand as much. As a result, not as much oxygen can get into your lungs, and therefore to your body.

Interstitial lung diseases can be broken down into two large groups:

• Those that have no known cause (idiopathic ILD)
• Those with an identifiable cause or that occur along with other diseases

There are several types of idiopathic ILD. Idiopathic pulmonary fibrosis (IPF) is the most common type. Less common types include:

• Acute interstitial pneumonitis (AIP)
• Cryptogenic organizing pneumonia or bronchiolitis obliterans organizing pneumonia (BOOP)
• Desquamative interstitial pneumonia (DIP)
• Lymphocytic interstitial pneumonia (LIP)
• Nonspecific interstitial pneumonitis (NSIP)
• Respiratory bronchiolitis interstitial lung disease (RBILD)

There are dozens of different causes of ILD.

• Autoimmune diseases (in which the immune system attacks the body) such as lupus, rheumatoid arthritis, sarcoidosis, and scleroderma
• Certain infections
• Certain medications (such as bleomycin, amiodarone, methotrexate, gold, infliximab, etanercept)
• Radiation therapy to the chest to treat Breast cancer, lymphoma, and other cancers
• Working with or around asbestos, coal dust, cotton dust, and silica dust

Cigarette smoking may increase the risk of developing some forms of ILD and may cause the disease to be more severe.

Symptoms

Shortness of breath is a key symptom of interstitial lung disease. People may breathe faster or need to take deep breaths.

• At first, shortness of breath is not severe and you may only notice it with exercise, climbing stairs, and other hard activities.
• Over time, you may notice it while bathing or dressing, and then while eating or talking.

Most people with this condition also have a dry cough. A dry cough means you do not cough up any mucus or sputum.

Over time, weight loss, muscle and joint pain, and fatigue are also present.

People with advanced ILD may have:

• Abnormal enlargement of the base of the fingernails (clubbing)
• Blue color of the lips, skin, or fingernails due to low blood oxygen levels (cyanosis)

Signs and tests

The health care provider will perform a physical exam. Dry, crackling breath sounds may be heard when listening to the chest with a stethoscope. The health care provider may notice nasal flaring.

The following tests may be done:

• Blood tests to check for connective tissue diseases
• Bronchoscopywith biopsy
• Chest x-ray
• CT scan of the chest
• Lung biopsy
• Measurement of the blood oxygen level at rest or during exertion
• Pulmonary function tests

Treatment

Treatment depends on the cause of the disease. Anti-inflammatory drugs, such as corticosteroids or drugs that suppress the immune system, are prescribed if an autoimmune disease is causing the problem.

If there is no specific treatment for the condition, therapy is aimed at making you more comfortable and supporting lung function.

• If you smoke, ask the doctor or nurse about referring you to someone who can help you stop smoking.
• People with low blood oxygen levels will receive oxygen therapy in the home. A respiratory therapist will help you set up oxygen for use in the home or outside of the home. Families need to learn proper storage and safety, and how to keep an oxygen supply available.
• Lung rehabilitation can provide support, including teaching patients different breathing methods, how to set up the home to save energy, and how to eat enough calories and nutrients.

Some patients with advanced ILD may need a lung transplant.

Support Groups

For additional information and resources, see lung disease support group.

Expectations (prognosis)

Chances of recovery or the disease getting worse depend on the cause, and how severe the disease was when it was first diagnosed.

Complications

• Pulmonary hypertension
• Respiratory failure
• Right-sided heart failure (cor pulmonale)

Calling your health care provider

Call your health care provider if:

• Your breathing is getting harder, faster, or more shallow than before
• You cannot get a deep breath, or need to lean forward when sitting
• You are having headaches more often
• You feel sleepy or confused
• You have a fever
• You are coughing up dark mucus
• Your fingertips or the skin around your fingernails is blue

Prevention

Avoid exposure to substances known to cause lung disease.

Quitting smoking can prevent ILD from getting worse.

People who are heavily exposed to known causes of occupational lung disease in the workplace are usually routinely screened for lung disease. These jobs can include coal miners, sand blasters, and ship workers.

References

Goldman L, Ausiello D. Cecil Medicine. 23rd ed. Philadelphia, Pa: Saunders; 2008.

American Thoracic Society/European Respiratory Society International Multidisciplinary Consensus. Classification of the Idiopathic Interstitial Pneumonias. Am J Respir Crit Care Med. 2002;165:277-304.