What is the treatment for pneumonitis?

Treatment for Pneumonitis

The treatment of pneumonitis should be based on severity grading, with corticosteroids as the mainstay therapy for symptomatic cases, discontinuation of the offending agent, and consideration of additional immunosuppressive agents for steroid-refractory cases. 1

Diagnosis and Evaluation

Before initiating treatment, proper diagnosis is essential:

• CT chest imaging is the preferred modality to identify ground-glass opacities, patchy nodular infiltrates, or interstitial patterns characteristic of pneumonitis 1
• Bronchoscopy with bronchoalveolar lavage (BAL) should be performed to exclude infections, especially in grade 2 or higher pneumonitis 1
• Transbronchial or surgical lung biopsy may be considered when the etiology is unclear, though not routinely required 1

Treatment Algorithm Based on Severity

Grade 1 (Asymptomatic)

• Close monitoring while continuing therapy may be appropriate, particularly for asymptomatic patients with isolated radiologic changes 1
• Monitor symptoms every 2-3 days 1
• Repeat chest CT prior to next scheduled dose of medication if drug-related pneumonitis is suspected 1

Grade 1-2 (Mild to Moderate Symptoms)

• Discontinue the suspected causative agent if pneumonitis is deemed a possible or likely cause 1
• Initiate oral corticosteroids with prednisone 1 mg/kg daily or equivalent 1
• Clinical assessment every 2-3 days initially, with radiological follow-up for grade 2 1
• Taper steroids over 4-6 weeks after recovery 1
• If drug therapy needs to be reintroduced, wait until steroid dose is ≤10 mg prednisone daily 1

Grade 3-4 (Severe Symptoms)

• Hospitalize the patient 1
• Permanently discontinue the offending agent 1
• Administer high-dose intravenous corticosteroids (methylprednisolone 2-4 mg/kg/day or equivalent) 1
• If no improvement after 48 hours, consider additional immunosuppressive strategies 1:
  • Infliximab
  • Mycophenolate mofetil (MMF)
  • Cyclophosphamide
• Taper steroids very slowly and carefully over 6 weeks or more 1

Special Considerations

Drug-Related Pneumonitis

• Improvement following cessation of drug administration without glucocorticoid therapy strongly supports the diagnosis of drug-related pneumonitis 1
• Clinical improvement with glucocorticoid therapy supports but does not definitively confirm the diagnosis, as other inflammatory processes may also respond to steroids 1
• Rechallenge with the suspected drug is rarely appropriate, especially when lung toxicity has been severe 1

Immune Checkpoint Inhibitor (ICI) Pneumonitis

• If infectious status cannot be reliably assessed, consider administering broad-spectrum antibiotics in parallel to immunosuppressive treatment in grade 3 pneumonitis 1
• For ICI-related pneumonitis, steroid tapering should be very slow (6+ weeks) as relapses during tapering have been reported 1
• Sarcoid-like reactions may occur with ICI therapy and require specific management approaches 1

Radiation Pneumonitis

• For uncomplicated radiation pneumonitis, oral prednisone (equivalent to 60 mg daily) is typically used 2
• For severe radiation pneumonitis, IV methylprednisolone for 3 days before transitioning to oral corticosteroids 2
• Initial steroid dose should be maintained for approximately 2 weeks, followed by a gradual weekly taper 2

Pitfalls and Caveats

• Recrudescence of pneumonitis signs and symptoms can occur following rapid steroid taper; a minimum 4-6 week taper is recommended 1
• Clinical improvement with steroids may be coincidental due to spontaneous recovery from a self-limited event (e.g., aspiration pneumonia) 1
• Pneumonitis may be difficult to distinguish from disease progression, infection, or other pulmonary complications 1
• In patients with preexisting lung diseases such as COPD or pulmonary fibrosis, diagnosis of pneumonitis is particularly challenging 1
• When using antibiotics for possible concurrent infection, be aware of potential QT prolongation with certain agents like azithromycin 3