What is the treatment for pneumonitis?

Treatment for 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

Diagnosis and Assessment

Before initiating treatment, proper diagnosis is essential:

• CT imaging is more reliable than chest radiographs for identifying pneumonitis
• Radiologic patterns include ground-glass opacities, patchy nodular infiltrates, and organizing pneumonia pattern
• For grade 2 or higher pneumonitis, consider:
  • Bronchoscopy with bronchoalveolar lavage to rule out infection
  • Nasal swab, sputum culture, blood cultures, and COVID-19 testing

Treatment Algorithm Based on Severity

Grade 1 (Mild) Pneumonitis

• Asymptomatic with radiographic changes only
• Management:
  • Withhold causative agent (if identified)
  • Monitor symptoms every 2-3 days
  • Repeat chest CT before next scheduled treatment
  • Consider resuming treatment if infiltrates resolve

Grade 2 (Moderate) Pneumonitis

• Symptomatic but not severely limiting ADLs
• Management:
  • Withhold causative agent
  • Start oral corticosteroids: prednisone 1 mg/kg daily
  • Clinical assessment every 2-3 days
  • Radiological follow-up recommended

Grade 3-4 (Severe) Pneumonitis

• Severely symptomatic, limiting self-care, or life-threatening
• Management:
  • Permanently discontinue causative agent
  • Hospitalization required
  • High-dose intravenous corticosteroids: methylprednisolone 2-4 mg/kg/day
  • If no improvement after 48 hours, consider additional immunosuppression:
    • IVIG (preferred for steroid-refractory cases) 2
    • Infliximab (caution: associated with higher mortality in some studies) 2
    • Mycophenolate mofetil or cyclophosphamide as alternatives

Corticosteroid Taper Protocol

• Minimum 4-6 week steroid taper to prevent recrudescence 3
• Taper example:
  • Start with full dose for 1-2 weeks
  • Reduce by 5-10 mg every 5-7 days
  • Monitor closely for symptom recurrence during taper

Special Considerations

Immune Checkpoint Inhibitor-Induced Pneumonitis

• Higher incidence with PD-1 inhibitors (3.6%) compared to PD-L1 inhibitors (1.3%) 3
• Combination immunotherapies increase risk significantly 3
• NSCLC patients have higher risk than melanoma patients 3
• Earlier onset in NSCLC (median 2.1 months) versus melanoma (median 5.2 months) 3

Bleomycin-Induced Pneumonitis

• Can occur at cumulative doses below 200 units 4
• Corticosteroids show significant clinical and radiographic improvement
• Prolonged steroid therapy often required over many months
• Tapering can lead to recurrence of symptoms and infiltrates 4

Monitoring Response

• Clinical symptoms (dyspnea, cough, oxygen requirements)
• Radiographic improvement
• Note: Pulmonary function tests may remain abnormal despite clinical improvement and should not be used as the sole monitoring parameter 4

Pitfalls and Caveats

• Steroid-refractory pneumonitis occurs in approximately 18.5% of cases 2
• Diffuse alveolar damage pattern on imaging is associated with worse outcomes 2
• Patients with pre-existing lung disease (COPD, pulmonary fibrosis) present diagnostic challenges 3
• Sarcoid-like reactions may mimic disease progression and require different management 3
• IVIG appears to have better outcomes than infliximab for steroid-refractory cases, with lower mortality (43% vs 100%) 2