Pneumonitis, radiation: 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.
Acute (early) radiation pneumonitis usually manifests itself 4 to 12 weeks after completion of radiation therapy. Symptoms include shortness of breath upon activity, cough, chest pain and low grade fever.
Radiation pneumonitis frequently may also be discovered serendipitously, as an incidental finding on chest X-ray in patients who have no symptoms.
Blood testing can indicate that inflammation is present but there are no specific blood tests that can make the diagnosis.
If radiation pneumonitis persists, it can lead to scarring of the lungs, referred to as radiation fibrosis. Radiation fibrosis typically occurs six to twelve months 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 and permanent.