Pneumonitis, Radiation

Key Features

• Acute disease usually presents 2–3 months after completion of radiation therapy

• Late disease may develop 6–12 months after completion of radiation

• "Radiation recall"

  • Characterized as an inflammatory reaction in the radiated region after treatment with a new round of chemotherapy – this phenomenon has also been reported with immune checkpoint inhibitors

  • Occasionally occurs in patients who are months to years removed from radiation therapy

• Radiographic findings correlate poorly with symptoms

• Resolution typically occurs after 2–3 weeks; death from acute respiratory distress syndrome (ARDS) is unusual

Clinical Findings

• Insidious onset of dyspnea, dry cough, chest fullness or pain, weakness, and fever

• Inspiratory crackles may be heard

• In severe disease, respiratory distress and cyanosis may be present

• Leukocytosis and elevated erythrocyte sedimentation rate (ESR) are common

Diagnosis

• Chest radiograph usually shows alveolar or nodular opacity limited to the irradiated area; air bronchograms are common

• Pulmonary function tests: reduced volumes, compliance, and diffusion capacity

• Hypoxemia

Treatment

• Aspirin, cough suppression, and bed rest

• Corticosteroid therapy

  • Not been proved effective

  • If given, prednisone (1 mg/kg/day orally) is usually used for 1 week; higher doses may be given in patients who are critically ill

  • The dose is then reduced to 20–40 mg/day for several weeks before a slow taper