Causes and Diagnoses

Causes and Diagnoses of Pulmonary Fibrosis

In many cases, the cause of pulmonary fibrosis is idiopathic, or unknown. In other patients, tests may point to more than one cause. Typical causes include:

  • Autoimmune and connective tissue diseases, including:
  • Occupational exposure to silica, asbestos, metal or coal dust
  • Long-term exposure to environmental irritants, such as grain dust, molds, bacteria, and bird and animal droppings
  • Smoking
  • Drug use
  • Radiation therapy
  • Certain medications

Diagnosing pulmonary fibrosis

Diagnosis of pulmonary fibrosis and other interstitial lung diseases starts with a thorough medical history and physical examination. Diagnostic tests include:

  • Blood tests: These may be ordered if hypersensitivity (allergic) reactions to environmental agents or connective tissue diseases are suspected.
  • Arterial blood gas: This blood test checks the amount of oxygen and carbon dioxide in your blood and measures your blood’s acidity.
  • Pulmonary function testing (PFT): Tests to determine the severity of your respiratory impairment, often using a spirometer, measure the volume of air inhaled and exhaled by your lungs.
  • Pulse oximetry: An oximeter measures the amount of oxygen in your blood with a sensor that’s clipped onto your finger.
  • Computed tomography (CT) scan: This high-resolution technology offers a more detailed, cross-section scan than an X-ray so your physician can specifically visualize the pulmonary interstitium.
  • Bronchoalveolar lavage: Using a bronchoscope, a sterile saline solution is introduced into the lungs and then suctioned out. The lung cells that come out with the solution can be examined for infection or other causes of pulmonary fibrosis.
  • Bronchoscope biopsy: Your physician can use a bronchoscope (a flexible tube with a small camera) that is inserted through your mouth or nose into the airways. Tiny instruments are then used to take a tissue sample.
  • Surgical biopsy: Our thoracic surgery partners use minimally invasive, state-of-the-art techniques for lung biopsy surgery, resulting in less pain and illness, and allowing for relatively short and uncomplicated hospital stays.

With either type of biopsy, the cells removed will be given to a pathologist to identify a cause. Your physician will determine the next course of action based on the pathologist's findings.

Diagnostic Tests

Related Resources

Pulmonary Fibrosis Foundation

Lung Biopsy Podcast: Get detailed information about how a lung biopsy is performed and how to prepare for it.