Treatment of Pneumonitis
The treatment of pneumonitis should be based on its severity grade, with corticosteroids being the mainstay of therapy for symptomatic cases, and additional immunosuppressive agents considered for steroid-refractory disease. 1
Types of Pneumonitis
Pneumonitis refers to inflammation of lung tissue, which can have various etiologies:
- Immune-related pneumonitis: Associated with immune checkpoint inhibitors (ICIs)
- Community-acquired pneumonia: Infectious etiology
- Drug-induced pneumonitis: From various medications
- Hypersensitivity pneumonitis: From environmental exposures
Treatment Algorithm Based on Severity
Grade 1 (Asymptomatic) Pneumonitis
- Withhold causative agent if identified
- Close monitoring with clinical assessment every 2-3 days
- Repeat chest CT before next scheduled dose of medication (if medication-related)
- May resume therapy if infiltrates resolve 1
Grade 2 (Mild to Moderate) Pneumonitis
- Withhold causative agent
- Oral corticosteroids: prednisone 1 mg/kg daily or equivalent 1
- Clinical assessment every 2-3 days initially
- Radiological follow-up recommended
- Taper steroids over 4-6 weeks after recovery
- For immune checkpoint inhibitor-related pneumonitis: delay reintroduction until prednisone dose ≤10 mg daily 1
Grade 3-4 (Severe) Pneumonitis
- Hospitalization required
- Permanently discontinue causative agent if identified
- High-dose intravenous corticosteroids: methylprednisolone 2-4 mg/kg/day 1
- If no improvement after 48 hours, consider additional immunosuppression:
- Infliximab
- Mycophenolate mofetil
- Cyclophosphamide 1
- Very slow steroid taper over 6+ weeks 1
Special Considerations
Infectious Workup
For grade 2 or higher pneumonitis, consider:
- Bronchoscopy with bronchoalveolar lavage to rule out infection 1
- Nasal swab, sputum culture, blood cultures, urine culture 1
- COVID-19 testing per institutional guidelines 1
Immune-Related Pneumonitis
- Higher incidence with PD-1 inhibitors (3.6%) compared to PD-L1 inhibitors (1.3%) 1
- Combination immunotherapies increase risk 1
- Higher rates in non-small cell lung cancer patients compared to melanoma patients 1
- Radiologic patterns include:
- Ground-glass opacities
- Patchy nodular infiltrates (predominantly lower lobes)
- Organizing pneumonia pattern 1
Sarcoid-like Reactions
- Can occur with immune checkpoint inhibitors
- May present with:
- Subpleural micronodular opacities
- Hilar lymphadenopathy
- Pleural effusions 1
- May require treatment if there is:
- Progressive radiographic change
- Persistent pulmonary symptoms
- Lung function deterioration
- Extrapulmonary involvement 1
Pitfalls and Caveats
- Recrudescence of pneumonitis can occur with rapid steroid taper; minimum 4-6 week taper recommended 1
- In patients with preexisting lung disease (COPD, pulmonary fibrosis), diagnosis of pneumonitis is particularly challenging 1
- Transbronchial biopsy is generally not required but may help rule out other etiologies like lymphangitic spread of tumor or infection 1
- For immune checkpoint inhibitor-related pneumonitis, steroid-refractory disease occurs when there is no improvement after 48 hours of corticosteroid therapy 1
- Sarcoid-like reactions may mimic disease progression on imaging and examination 1
By following this structured approach to pneumonitis treatment based on severity grading, clinicians can optimize outcomes while minimizing complications from both the disease and its treatment.