Management of Pneumonitis

Severity Grading and Initial Management

The American College of Physicians recommends that pneumonitis treatment is severity-based: grade 1 requires monitoring only, grade 2 requires immediate drug discontinuation plus oral prednisone 1 mg/kg daily, and grade 3-4 requires hospitalization with high-dose IV methylprednisolone 2-4 mg/kg/day 1
For grade 1 pneumonitis, continue the causative therapy with close monitoring without initiating corticosteroids at this stage, and monitor symptoms and oxygen saturation every 2-3 days using pulse oximetry 1, 2
For grade 2 pneumonitis, immediately discontinue the suspected causative agent and initiate oral prednisone 1 mg/kg daily or equivalent, and taper steroids over a minimum of 4-6 weeks after clinical recovery 1, 2, 3
For grade 3-4 pneumonitis, hospitalize immediately and permanently discontinue the offending agent, and administer high-dose IV methylprednisolone 2-4 mg/kg/day or equivalent, and taper steroids very slowly over 6+ weeks minimum 1, 2, 3

The American Thoracic Society recommends that CT chest imaging is the preferred modality, showing ground-glass opacities, patchy nodular infiltrates, or interstitial patterns 2
Bronchoscopy with BAL should be performed for grade 2 or higher pneumonitis to exclude infections 2

The National Comprehensive Cancer Network recommends that combination immunotherapy increases the risk of pneumonitis 3-fold, with incidence reaching 10% versus 3% for monotherapy 1, 3
The median time to onset of pneumonitis is 34 weeks but ranges from 1.5 to 127 weeks 4
Patients with non-small cell lung cancer have more treatment-related deaths from pneumonitis 3
Delay immunotherapy rechallenge until daily steroid dose ≤10 mg prednisone equivalent 2
Approximately 2% of patients develop chronic pneumonitis persisting despite immune checkpoint inhibitor discontinuation and may not resolve after >3 months of corticosteroids 3, 4