Idiopathic pulmonary fibrosis, or IPF, is a condition that causes progressive scarring of the lungs. Fibrous scar tissue builds up in the lungs over time, affecting their ability to provide the body with enough oxygen. The cause of the condition is unknown.
IPF affects more than 100,000 people in the United States, with 30,000 to 40,000 new cases diagnosed each year. Typically the disease is found in people between the ages of 50 and 70 and affects men more frequently than women. Most patients are former smokers. There are no proven risk factors for IPF, but a minority of patients does have a family history of lung scarring.
Symptoms and signs of IPF often appear gradually and include:
Shortness of breath, particularly during or after physical activity
Chronic, dry hacking cough
Crackles in the lungs heard through a stethoscope
Rounding of the fingernails, a condition called clubbing
Symptoms of IPF may mimic those of other diseases that cause lung scarring, so diagnosing IPF often involves ruling out other conditions. Several visits with your doctor may be needed to finalize your diagnosis and treatment approach.
Diagnosis
Diagnosing idiopathic pulmonary fibrosis, or IPF, requires input from pulmonologists, radiologists and in many cases, pathologists experienced in evaluating patients with interstitial lung disease. A face-to-face discussion among these various specialists is often necessary to make an accurate diagnosis.
To determine if you have IPF, your doctor will start by conducting a thorough medical history and physical examination. The medical history will include discussing other medical problems you have that could be related to lung scarring, such as connective tissue diseases, and reviewing any medications you're taking. The physical exam will include listening to your chest with a stethoscope to check for a crackling sound and carefully examining your skin and joints.
In addition to a thorough medical history and physical exam, your doctor may conduct the following tests:
Pulmonary Function Test (PFT) — This test involves a series of breathing exercises that measure the airflows, volume of air in your lungs and ability of your lungs to extract oxygen from the air. This allows your doctor to assess the function of your lungs.
High Resolution Computed Tomography (HRCT) — This is a special type of CT scan that provides your doctor with high-resolution images of your lungs. Images are taken in several different ways, including lying on your back (supine), lying on your chest (prone) and while breathing air out of your chest (dynamic expiration). These images are extremely valuable in determining whether or not you have IPF. Having an HRCT is very similar to having a regular CT scan; they both take only a few minutes.
Blood Tests — Also called serologies, blood tests may be ordered to look for evidence of connective tissue diseases such as rheumatoid arthritis or scleroderma. Some patients with these connective tissue diseases develop lung problems before the more typical signs and symptoms appear.
Six-Minute Walk Test — This test evaluates the distance you can walk within six minutes and the oxygen saturations, measured by finger or ear probe, you achieve while walking.
Bronchoscopy — In this test, the doctor passes a flexible fiberoptic scope, about the diameter of a pencil, into the lungs to take fluid and tissue samples. This test doesn't require an overnight stay in the hospital. It's unclear if bronchoscopy provides any benefit in diagnosing IPF, but it may be performed in certain circumstances.
Surgical Lung Biopsy — Some patients need this test to definitively diagnose IPF. A cardiothoracic surgeon performs the surgical lung biopsy, usually with small tools and cameras through one-inch-long incisions. Patients will need to stay in the hospital for a few days.
Treatment
Unfortunately, there is currently no cure for idiopathic pulmonary fibrosis (IPF), and there is no proven medication therapy to treat it. Medical studies suggest a potential role for several therapies, listed below, but further study is needed.
Pirfenidone — Data from three large studies of pirfenidone have suggested a benefit for IPF. Pirfenidone appears to slightly slow the decline in lung function. This drug is not currently approved for use in the United States but will be reviewed by the Federal Drug Administration (FDA) sometime in 2009.
Acetylcysteine (NAC) — Data from a large study adding acetylcysteine to traditional medication therapies that include prednisone suggest it may help, but there's no consensus on whether or not the results are definitive. Acetylcysteine is available over the counter at most pharmacies and stores that carry supplements.
Prednisone plus azathioprine — Combining prednisone with a second drug such as azathioprine, mycophenolate or cyclophosphamide has been used to treat IPF, but recent evidence suggests this approach isn't beneficial. If used to treat IPF, these medications should generally be combined with acetylcysteine, based on a recent study showing this combination to be more effective.
Ongoing studies of other medications for IPF have shown initial promise but need more research.
Pulmonary rehabilitation — a structured exercise and educational program designed for patients with chronic lung disease — is important for patients with IPF. We will also pay careful attention to any other medical problems associated with IPF, such as gastroesophageal reflux disease and pulmonary hypertension. Lastly, lung transplant may be an effective treatment option for some patients.
