Drug or radiation exposure-related interstitial lung disease

Drug or radiation exposure-related interstitial lung disease (also known as drug-induced or radiation-induced interstitial lung disease, or iatrogenic pneumonitis) is a group of lung disorders caused by exposure to certain medications, therapeutic drugs, or ionizing radiation. These exposures can trigger inflammation and fibrosis (scarring) of the lung interstitium — the tissue and space surrounding the air sacs (alveoli) — leading to impaired gas exchange and progressive respiratory compromise. The condition primarily affects the pulmonary system but can have systemic consequences due to chronic hypoxemia (low blood oxygen levels). Key symptoms include progressive dyspnea (shortness of breath), persistent dry cough, fatigue, and in some cases fever and chest discomfort. Symptoms may develop acutely within days to weeks of exposure or insidiously over months. Numerous drugs are implicated, including certain chemotherapeutic agents (e.g., bleomycin, methotrexate, cyclophosphamide), amiodarone, nitrofurantoin, and targeted cancer therapies. Radiation-induced interstitial lung disease typically occurs following thoracic radiotherapy for cancers such as breast or lung cancer. Diagnosis is based on clinical history of drug or radiation exposure, characteristic findings on high-resolution CT imaging (ground-glass opacities, reticular patterns, consolidation), pulmonary function testing showing restrictive defects, and exclusion of other causes such as infection. Treatment centers on prompt identification and discontinuation of the offending drug or cessation of radiation exposure when possible. Corticosteroids are commonly used to reduce inflammation, particularly in acute or subacute presentations. Supportive care including supplemental oxygen therapy and pulmonary rehabilitation may be necessary. In severe or progressive cases where fibrosis has developed, the damage may be irreversible, and lung transplantation may be considered in select patients. Prognosis varies widely depending on the causative agent, the duration of exposure, and the extent of lung damage at the time of diagnosis.

Common questions about Drug or radiation exposure-related interstitial lung disease