Pulmonary (PULL-mun-ary) fibrosis is a condition in which tissue deep in your lungs becomes thick and stiff, or scarred, over time. The development of the scarred tissue is called fibrosis. As the lung tissue becomes thicker, your lungs lose their ability to move oxygen into your bloodstream, and your brain and other organs donít receive the oxygen they need.
In some cases, doctors can find out what is causing the fibrosis. But in most cases, they canít find a cause. They call these cases idiopathic pulmonary fibrosis (IPF). IPF is a serious condition. IPF affects mostly people 50 to 75 years of age.
IPF varies from person to person. In some people, the lung tissue quickly becomes thick and stiff. In others, the process is much slower, and in some people, the condition stays the same for years.
There is no cure for IPF yet. Many people live only about 3 to 5 years after diagnosis. The most common cause of death related to IPF is respiratory failure. Other causes include:
- Pulmonary arterial hypertension
- Heart failure
- Pulmonary embolism
- Lung cancer
Some people may be more likely to develop IPF because of their genes (the basic units of heredity). If more than one member of your family has IPF, the condition is called familial idiopathic pulmonary fibrosis.
How the Lungs Work
The air that you breathe in through your nose or mouth travels down through your windpipe (trachea) into two tubes in your lungs called the bronchial tubes, or airways.
The airways are shaped like an upside-down tree with many branches. The trachea is the trunk. It splits into two bronchial tubes, or bronchi. Thinner tubes called bronchioles branch out from the bronchi.
The bronchioles end in tiny air sacs called alveoli. These air sacs have very thin walls, and small blood vessels called capillaries run through them. There are about 300 million alveoli in a normal lung. Scientists say that if the air sacs were opened up and placed next to one another, they would cover a tennis court.
When the air that you've just breathed in reaches these air sacs, the oxygen in the air passes through the air sac walls into the blood in the capillaries. The blood then flows into larger veins, which carry it to the heart. Your heart then pumps the oxygen-rich blood to all your bodyís organs. These organs canít function without an ongoing supply of oxygen.
In idiopathic pulmonary fibrosis, scarring begins in the air sac walls and the spaces around them. It makes the walls of the air sacs thicker. As a result, oxygen canít move from the air sacs into the bloodstream.
Other Names for Idiopathic Pulmonary Fibrosis
Causes of Idiopathic Pulmonary Fibrosis
- Idiopathic diffuse interstitial pulmonary fibrosis
- Pulmonary fibrosis of unknown cause
- Pulmonary fibrosis
- Cryptogenic fibrosing alveolitis
- Usual interstitial pneumonitis
- Diffuse fibrosing alveolitis
Doctors donít 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.
Signs and Symptoms of Idiopathic Pulmonary Fibrosis
The signs and symptoms of idiopathic pulmonary fibrosis (IPF) develop over time. They may not even begin to appear until the disease has done serious damage to your lungs. Once they do appear, they are likely to become worse over time.
The most common signs and symptoms are:
- Shortness of breath. This is usually the main symptom. At first, you may be short of breath only during exercise. Over time, you are likely to feel breathless even at rest.
- A dry, hacking cough that doesnít get better when you treat it with over-the-counter cough medicines. Over time, you may have repeated bouts of coughing that you can't control.
Other signs and symptoms that you may develop over time include:
- Rapid, shallow breathing
- Gradual, unintended weight loss
- Fatigue (tiredness) or malaise (a general feeling of being unwell)
- Aching muscles and joints
- Enlargement of the ends of the fingers or toes, which is called clubbing
IPF may lead to other medical conditions, including: collapsed lung, lung infections, blood clots in the lungs, and lung cancer.
As your condition gets worse, you may develop other potentially life-threatening conditions, including respiratory failure, pulmonary arterial hypertension, and heart failure.
Idiopathic pulmonary fibrosis (IPF) produces the same kind of scarring and symptoms as some other lung diseases. This makes it hard to diagnose. Seeking medical help, preferably from a pulmonologist (a doctor who specializes in lung problems), as soon as you have symptoms is important.
To diagnose IPF, your doctor will ask about your medical history, perform a physical exam, and do several tests to rule out other causes of your symptoms and learn how badly your lungs are damaged.
A complete medical history is important. Your doctor will ask about:
- Your age
- Your history of smoking
- Things in the air at your job or elsewhere that could irritate your lungs
- Your hobbies
- Your history of legal and illegal drug use
- Other medical conditions that you have that can trigger an immune system response
- Your family's medical history
- How long you've had symptoms
There is no single test for diagnosing IPF. Your doctor will probably conduct several different tests, including the following.
Chest X Ray
A chest x ray takes a picture of your heart and lungs. It can show shadows that suggest scar tissue. Many people with IPF have normal chest x rays at the time theyíre diagnosed.
High-Resolution Computerized Tomography
High-resolution computerized tomography (HRCT) scan is an x ray that provides sharper and more detailed images than a regular chest x ray. It can show scar tissue and how much lung damage you have. This test can help your doctor spot IPF at an early stage or rule it out. It also can help your doctor decide how likely you are to respond to treatment.
Lung Function Tests
Your doctor will do a breathing test called spirometry to find out how much lung damage you have. A spirometer is a device that measures how much air you can blow out of your lungs after taking a deep breath. It also measures how fast you can breathe the air out. If there is a lot of scarring in your lungs, you will not be able to move a normal amount of air out of them.
Your doctor attaches a small device to your finger or earlobe to see how much oxygen is in your bloodstream.
Arterial Blood Gas Test
The doctor takes a small amount of blood from an artery in your arm, usually in your wrist. Itís then checked for oxygen and carbon dioxide levels. This test is a more accurate way to check the level of oxygen in your bloodstream. Your blood can also be tested to see whether you have an infection that may be causing your symptoms.
Skin Test for Tuberculosis
Your doctor injects a small amount of a substance that reacts to tuberculosis (TB) under the top layer of skin on one of your arms. If you have a positive reaction, a small hard lump will develop at the injection site 48 to 72 hours after the test. This test is done to rule out TB.
Exercise testing is used to find out how well your lungs move oxygen and carbon dioxide in and out of your bloodstream when youíre active. During this test, you walk or pedal on an exercise machine for a few minutes. Electrodes attached to your chest and an EKG (electrocardiogram) machine show your heart rate, a blood pressure cuff monitors your blood pressure, and a pulse oximeter attached to a finger or ear lobe shows how much oxygen is in your blood.
Sometimes doctors place a catheter in an artery in one of your arms to draw samples of your blood that will provide a more accurate measure of the oxygen and carbon dioxide in it. They may also ask you to breathe into a tube that separates the air you breathe out from room air and provides a precise measure of the amount of oxygen youíve taken in and carbon dioxide you're breathing out.
Looking at samples of tissue from several places in your lungs under a microscope is the best way for your doctor to diagnose IPF. A lung biopsy can help your doctor rule out other causes of your condition, such as sarcoidosis, cancer, or infection. It can also show your doctor how far your condition has advanced.
Doctors use several different procedures to obtain samples of your lung tissue:
Bronchoscopy. Your doctor inserts a flexible, rubber tube with a tiny light and camera on the end through your nose or mouth into your lungs to look at your airways. He or she then inserts a forceps through the tube to collect tissue to examine. This procedure is usually done under local anesthesia on an outpatient basis.
Bronchoalveolar lavage. During bronchoscopy, your doctor may inject a small amount of salt water (saline) through the bronchoscope into your lungs. This fluid washes the lungs and helps bring up cells from the area around the air sacs for examination under a microscope.
Video-assisted thoracoscopy. This is the procedure that doctors use most to obtain lung tissue. Your doctor inserts a small, lighted tube with a camera (endoscope) into your chest through small incisions between your ribs. The endoscope provides a video image of the lungs and allows your doctor to collect samples of tissue. This procedure must be done in the hospital, under general anesthesia.
Thoracotomy. Your doctor removes a few small pieces of lung tissue through an incision in the chest wall between your ribs. Thoracotomy is done in the hospital under general anesthesia.
The goals of treating idiopathic pulmonary fibrosis (IPF) are to prevent more lung scarring, relieve your symptoms, maintain your ability to be active and get around, keep you healthy, and improve your quality of life.
Treatment canít remove scarring that has already happened. As a result, diagnosing and treating IPF as early as possible, before a lot of scarring has taken place, is very important.
Treatment is usually based on your age, medical history, any medical problems you may have, and how much the IPF has advanced.
Treatments can include:
- Medicines to reduce inflammation (swelling) in your lungs and/or prevent more scarring
- Oxygen therapy
- Pulmonary rehabilitation
- Lung transplantation
The main treatment for IPF is medicine to reduce inflammation. Many doctors also add a medicine to suppress your body's immune system. These treatments can prevent further scarring and increase survival time in some people, but they donít work for everyone.
When the amount of oxygen in your blood gets low, you may need oxygen therapy to help reduce your shortness of breath and let you be more active. Oxygen is usually given through nasal prongs or a mask. At first, you may need it only during exercise and sleep. As your condition gets worse, you may need it all the time.
Pulmonary rehabilitation is now the standard of care for people with ongoing lung disease. It usually involves treatment by a team of specialists in a specialized clinic. The goal is to teach you how to manage your condition and function at your best.
Services usually include:
- Physical conditioning training
- Breathing exercises and retraining, so that it takes less energy for you to breathe
- Anxiety, stress, and depression management
- Nutritional counseling
- Support groups
Early referral for surgery to replace one of your lungs with a healthy lung from a human donor is usually recommended if you:
- Are younger than 65
- Have no other medical problems
- Are not being helped by medicines
Single lung transplantation can improve your quality of life and help you live longer.
Complications can include rejection by the body of the transplanted lung and infection. You may have to take medicines for life to reduce the chances that your body will reject the transplanted lung.
Because the supply of donor lungs is limited, asking for an evaluation for a transplant as soon as possible is important.