Radiation-induced lung injury

The radiation pneumonitis, radiation pneumonitis synonymous is the name of an interstitial lung disease. It can occur as an acute or chronic side effect after large-volume irradiation in radiotherapy.

Definition

The radiation pneumonitis is a toxic inflammatory reaction of the lung parenchyma after irradiation of a lung cancer, breast cancer, esophageal cancer or mediastinal tumor (eg lymphoma ) dar. rays total dose, size of the radiation field and fractionation determine the manifestation probability. Below a total dose of 20 Gy this radiation reaction does not occur and more than 60 Gy ( applied within six weeks) it occurs almost regularly. The latency between the end of irradiation and occurrence of radiation pneumonitis is a few days up to six months, but usually four to six weeks.

Pathogenesis

Dysfunction of the endothelial cells and pneumocytes, the strahlenempfindlichsten structures of the alveoli, lead in the acute stage to an interstitial and alveolar edema. In the further course occurs dominated by lymphocytes and macrophages alveolitis, which merges into a fibrosing - proliferative phase. The radiation pneumonitis is limited usually to the irradiated area. However, changes outside of the radiation field may occur and indicate a clinically schwergradigen course. These findings are interpreted as an immune response to neo-antigens, which are caused by irradiation.

Symptoms

Unlike an acute pneumonia, many patients remain asymptomatic with radiological signs of radiation reaction, some develop a dry cough, weakness and shortness of breath to the dyspnea. In the further course either for complete healing, or due to progressive fibrosis and Gefäßsklerosierung to pulmonary fibrosis.

Diagnostics

Due to the temporal relationship, the diagnosis is easy. Radiographic changes after the acute phase streaky condensations associated with shrinkage. Functionally, there are a restrictive lung disorder and a pronounced hypoxemia.

Therapy

Treatment is usually in the administration of glucocorticoids (1 mg / kg body weight), but the effect is often unsatisfactory. In acute manifestation and great expansion of radiation pneumonitis may be necessary in more realistic forecast intubation with mechanical ventilation. To prevent bacterial superinfection, an additional antibiotic treatment is recommended.