Radiation pneumonitis: Inflammation of the lungs as a result of radiation. Although the radiation can be from various sources including accidents, today it is usually from radiation therapy.
Radiation pneumonitis typically occurs after radiation treatments for cancers within the chest or breast.
Radiation pneumonitis frequently is discovered serendipitously, as an incidental finding on chest x-ray in patients who have no symptoms.
Blood testing can indicate inflammation is present in the body. Abnormally white blood count and sedimentation rates are common.
If radiation pneumonitis persists, it can lead to scarring of the lungs, referred to as radiation fibrosis. Radiation fibrosis typically occurs a year after the completion of radiation treatments.
Radiation pneumonitis is often reversible with medications that reduce inflammation, such as cortisone drugs (prednisone and others).
Radiation fibrosis is usually irreversible: permanent.