What Causes Idiopathic Pulmonary Fibrosis?

Doctors don't know what causes idiopathic pulmonary fibrosis (IPF). They think that something inside or outside of the lungs attacks the lungs again and again over time. These attacks injure the lungs and cause scarring in the tissue inside and between the air sacs. This makes it harder for oxygen to pass through the air sac walls into the bloodstream.

Doctors think the following things may increase your chances of developing IPF:

• Cigarette smoking
• Viral infections, including Epstein Barr virus (which causes mononucleosis), influenza A virus, hepatitis C virus, HIV-a virus, and herpes virus 6
• Exposure to environmental pollutants, including inorganic dust (silica and hard metal dusts), organic dust (bacteria and animal proteins), and gases and fumes
• Use of certain medicines, including:
  • Nitrofurantoin and sulfasalazine, which are antibiotics used mostly to treat urinary tract infections, ulcerative colitis, and rheumatoid arthritis
  • Medicines to keep your heartbeat regular (for example, amiodarone or propranolol)
  • Chemotherapy or cancer medicines, such as methotrexate, cyclophosphamide, and bleomycin

Your genes may also play a role in the development of IPF. Some families have at least two members with IPF.

Scientists have found that 9 out of 10 people with IPF also have gastroesophageal reflux disease (GERD). As a result, some scientists think that some people who have GERD may breathe in tiny drops of acid from their stomachs on a regular basis. The acid may then injure the lungs and lead to IPF. More research must be done to confirm this.