Pneumonitis

General inflammation of lung tissue

Pneumonitis describes general inflammation of lung tissue. Possible causative agents include radiation therapy of the chest, exposure to medications used during chemo therapy, the inhalation of debris (e. g., animal dander), aspiration, herbicides or fluorocarbons and some systemic diseases. If unresolved, continued inflammation can result in irreparable damage such as pulmonary fibrosis. The distinction between pneumonia and pneumonitis can be further understood with pneumonitis being the encapsulation of all respiratory infections (incorporating pneumonia and pulmonary fibrosis as major diseases), and pneumonia as a localized infection. For most infections, the immune response of the body is enough to control and apprehend the infection within a couple days, but if the tissue and the cells can't fight off the infection, the creation of pus will begin to form in the lungs which then hardens into lung abscess or suppurative pneumonitis.

Pneumonitis can be separated into several distinct categories based upon causative agent. Hypersensitivity Pneumonitis (Extrinsic Allergenic Alveolitis) describes the inflammation of alveoli which occurs after inhalation of organic dusts (oxford). These particles can be proteins, bacteria, or mold spores and are usually specific to an occupation. Acute Interstitial Pneumonitis can result from many different irritants in the lungs and usually is resolved in under a month. Radiation pneumonitis occurs in approximately 30% of advanced lung cancer patients treated with radiation therapy. A lung injury after the inhalation of habitual gastric contents. The production of anti inflammatory proteins, and the degeneration of mRNA encoding inflammatory proteins, can also be increased by a high concentration of corticosteroids. These responses can help mitigate the inflammation seen in pneumonitis and reduce symptoms. Certain immune modulating treatments may be appropriate for patients with chronic pneumonitis. Azathioprine and mycophenolate are two particular treatments that have been associated with an improvement of gas exchange. Patients with chronic pneumonitis also may be evaluated for lung transplantation.