(See also Overview of Idiopathic Interstitial Pneumonias Overview of Idiopathic Interstitial Pneumonias Idiopathic interstitial pneumonias are interstitial lung diseases that have no known cause that have some similarities in symptoms and how they affect the lungs. Some types of these diseases... read more .)
The disease usually begins between the ages of 40 and 60 and affects men and women equally. Cigarette smoking does not appear to increase the risk of developing cryptogenic organizing pneumonia.
Almost 75% of people have progressively worsening cough and shortness of breath upon exertion, typically for less than 2 months before seeking medical attention. A flu-like illness, with a cough, fever, a feeling of illness (malaise), fatigue, and weight loss, heralds the onset in about 50% of people.
Diagnosis of Cryptogenic Organizing Pneumonia
Chest computed tomography
Sometimes lung biopsy
Doctors do not find any specific abnormalities on routine laboratory tests. During a physical examination, when doctors listen to the lungs with a stethoscope, they frequently hear crackling sounds and occasionally squeaking sounds as the person inhales. Pulmonary function testing Pulmonary Function Testing (PFT) Pulmonary function tests measure the lungs' capacity to hold air, to move air in and out, and to absorb oxygen. Pulmonary function tests are better at detecting the general type and severity... read more 
usually shows that the amount of air the lungs can hold is below normal. The amount of oxygen in the blood is often low at rest and is even lower during exercise.
A chest x-ray can help doctors make the diagnosis, but it is often not conclusive. Computed tomography (CT) may be done, and sometimes the findings are typical enough to allow doctors to make a diagnosis without ordering additional tests.
In other cases, to confirm the diagnosis, doctors do a lung biopsy using a bronchoscope Bronchoscopy Bronchoscopy is a direct visual examination of the voice box (larynx) and airways through a viewing tube (a bronchoscope). A bronchoscope has a camera at the end that allows a doctor to look... read more 
. Many times, a larger sample is needed and must be removed surgically.
Treatment of Cryptogenic Organizing Pneumonia
Corticosteroids
When treated with corticosteroids, most people recover quickly. However, symptoms may later return, and prolonged treatment is often necessary. If the disease recurs, repeat treatment with corticosteroids is usually effective.
