Idiopathic pulmonary fibrosis is scarring or thickening of the lungs without a known cause.

No one knows what causes pulmonary fibrosis or why some people get it. It causes the lungs to become scarred and stiffened. This stiffening makes it increasingly difficult to breathe. In some people the disease gets worse quickly (over months to a few years), but other people have little worsening of the disease over time.

The condition is believed to result from an inflammatory response to an unknown substance. "Idiopathic" means no cause can be found. The disease occurs most often in people between 50 - 70 years old.

• Chest pain (occasionally)
• Cough (usually dry)
• Decreased tolerance for activity
• Shortness of breath during activity that lasts for months or years and over time will also occur at rest

The health care provider will perform a physical exam and ask questions about your medical history. Your doctor will ask whether you have been exposed to asbestos.

Patients with idiopathic pulmonary fibrosis have abnormal breath sounds called crackles. Patients with advanced disease may have blue-colored skin (cyanosis) around the mouth or in the fingernails due to low oxygen.

Examination of the fingers and toes may show abnormal enlargement of the fingernail bases (clubbing).

Tests that help diagnose idiopathic pulmonary fibrosis include the following:

• Bronchoscopy with transbronchial lung biopsy
• Chest CT scan
• Chest x-ray
• Measurements of blood oxygen level
• Pulmonary function tests
• Surgical lung biopsy
• Tests for connective tissue diseases such as rheumatoid arthritis, lupus, or scleroderma