Management of Pneumonitis

Diagnosis and Evaluation

• The European Society for Medical Oncology recommends CT chest imaging as the preferred modality to identify ground-glass opacities, patchy nodular infiltrates, or interstitial patterns characteristic of pneumonitis 1, 2
• Bronchoscopy with bronchoalveolar lavage (BAL) should be performed to exclude infections, especially in grade 2 or higher pneumonitis, as suggested by the American College of Chest Physicians 3, 4
• Transbronchial or surgical lung biopsy may be considered when the etiology is unclear, though not routinely required, according to the American Society of Clinical Oncology 5, 1

Treatment Algorithm Based on Severity

• For grade 1 pneumonitis, the American Society of Clinical Oncology recommends close monitoring while continuing therapy, particularly for asymptomatic patients with isolated radiologic changes 3
• The European Society for Medical Oncology suggests monitoring symptoms every 2-3 days for grade 1 pneumonitis 4
• For grade 1-2 pneumonitis, the American College of Chest Physicians recommends discontinuing the suspected causative agent and initiating oral corticosteroids with prednisone 1 mg/kg daily or equivalent 3, 4, 6
• The American Society of Clinical Oncology recommends tapering steroids over 4-6 weeks after recovery for grade 1-2 pneumonitis 4, 6
• For grade 3-4 pneumonitis, the European Society for Medical Oncology suggests hospitalizing the patient, permanently discontinuing the offending agent, and administering high-dose intravenous corticosteroids (methylprednisolone 2-4 mg/kg/day or equivalent) 4, 6
• The American College of Chest Physicians recommends considering additional immunosuppressive strategies, such as infliximab, mycophenolate mofetil (MMF), or cyclophosphamide, if no improvement after 48 hours 4, 6, 5

Special Considerations

• The American Society of Clinical Oncology notes that improvement following cessation of drug administration without glucocorticoid therapy strongly supports the diagnosis of drug-related pneumonitis 3
• The European Society for Medical Oncology suggests that clinical improvement with glucocorticoid therapy supports but does not definitively confirm the diagnosis of drug-related pneumonitis 3
• For immune checkpoint inhibitor (ICI) pneumonitis, the American College of Chest Physicians recommends administering broad-spectrum antibiotics in parallel to immunosuppressive treatment in grade 3 pneumonitis, if infectious status cannot be reliably assessed 4, 6
• The American Society of Clinical Oncology suggests that steroid tapering should be very slow (6+ weeks) as relapses during tapering have been reported for ICI-related pneumonitis 4, 6

Corticosteroids in Immunotherapy-Related Pneumonitis

Treatment Approach

• The American Society of Clinical Oncology recommends corticosteroids as the first-line treatment for symptomatic immunotherapy-related pneumonitis, with clinical improvement reported in over 80% of cases, and treatment should be initiated immediately based on severity grading 7, 8
• For grade 2 pneumonitis, the European Society for Medical Oncology suggests discontinuing immunotherapy immediately and initiating oral prednisone 1 mg/kg daily or equivalent 9
• For grade 3-4 pneumonitis, hospitalization is recommended, and high-dose IV methylprednisolone 2-4 mg/kg/day or equivalent should be administered 9

Management of Steroid-Refractory Disease

• The American Society of Clinical Oncology recommends adding second-line immunosuppression, such as infliximab, mycophenolate mofetil, intravenous immunoglobulin, or cyclophosphamide, if no improvement is seen after 48 hours of corticosteroid therapy 7, 9

Diagnostic Considerations

• The American College of Radiology notes that CT chest imaging showing ground-glass opacities, patchy nodular infiltrates, or interstitial patterns is characteristic of immunotherapy-related pneumonitis 7, 8
• Transbronchial biopsy may help distinguish chronic organizing pneumonia-like patterns or exclude malignancy/infection, according to the American Thoracic Society 7, 8

Treatment Duration and Tapering

• The European Society for Medical Oncology recommends tapering steroids over 4-6 weeks minimum after recovery for grade 2 pneumonitis, and 6+ weeks for grade 3-4 pneumonitis 9
• Delaying immunotherapy rechallenge until daily steroid dose ≤10 mg prednisone equivalent is advised by the American Society of Clinical Oncology 9

Mechanical Ventilation Strategy for Acute Interstitial Pneumonitis

Ventilatory Management

• For patients with acute interstitial pneumonitis requiring invasive respiratory support, use low‑tidal‑volume ventilation (approximately 6 mL per kilogram of ideal body weight) when diffuse bilateral infiltrates are present, as this approach is associated with improved outcomes in recent clinical data. 10

Evidence‑Based Management of Drug‑Induced Pneumonitis

Diagnostic Imaging

• High‑resolution CT of the chest is essential for pattern recognition: ground‑glass opacities indicate an acute inflammatory process, patchy nodular infiltrates suggest hypersensitivity pneumonitis, and a diffuse alveolar‑damage (DAD) pattern identifies the most severe disease and the highest toxicity grades. 11

Role of Lung Biopsy

• Transbronchial or surgical lung biopsy should be reserved for cases in which the etiology remains unclear after the initial clinical and radiologic work‑up. 11

Outcomes Specific to Immune Checkpoint Inhibitor (ICI) Pneumonitis

• Fatal ICI‑related pneumonitis occurs in approximately 0.2 % of treated patients and accounts for about 35 % of all deaths attributed to PD‑1/PD‑L1 blockade. 11
• Rapid tapering of corticosteroids after recovery can precipitate pneumonitis flare‑ups even when immunotherapy is not resumed. 11

Supplemental Oxygen and Fluid Management

• Supplemental oxygen should be titrated to maintain arterial oxygen tension > 8 kPa (PaO₂ > 60 mm Hg) and peripheral saturation > 92 %. 12
• In uncomplicated pneumonitis, high‑concentration oxygen can be administered safely; patients with pre‑existing chronic obstructive pulmonary disease require repeated arterial blood‑gas analysis to guide therapy. 12
• Assessment for volume depletion and provision of intravenous fluids are recommended when clinically indicated. 12

Clinical Monitoring

• Vital signs, respiratory rate, pulse, blood pressure, mental status, oxygen saturation, and inspired oxygen concentration should be recorded at least twice daily. 12

Radiographic Follow‑Up

• A repeat chest radiograph is advised at six weeks in patients who have persistent symptoms, signs, or radiologic abnormalities. 12

Discharge Planning

• If the patient has achieved satisfactory clinical recovery, a formal clinical review is not required before hospital discharge. 12

Consideration of Bronchoscopy Post‑Recovery

• For patients with lingering radiographic abnormalities, bronchoscopy may be performed to clear retained secretions, obtain cultures, and exclude endobronchial pathology. 12