[Acute interstitial pneumonia in patient with rheumatoid arthritis treated with leflunomide]

Area of Science:

• Rheumatology
• Pulmonology
• Pharmacology

Background:

• Leflunomide (LEF) is a disease-modifying anti-rheumatic drug (DMARD) for rheumatoid arthritis (RA).
• While effective, LEF carries a risk of interstitial lung disease (ILD).
• Identified risk factors for LEF-induced ILD include pre-existing ILD, smoking, low body weight, and loading doses.

Observation:

• A 59-year-old male with RA, a history of smoking, and prior methotrexate (MTX) treatment was administered LEF.
• Approximately two months post-LEF initiation, the patient presented with dyspnea, non-productive cough, and fever.
• Clinical and radiological findings were consistent with acute pneumonia.

Findings:

• The patient received intensive treatment including methylprednisolone pulse, prednisone, and cyclophosphamide.
• Despite aggressive management, the patient's condition deteriorated.
• The patient ultimately succumbed to respiratory failure, indicative of severe LEF-induced ILD.

Implications:

• This case highlights the potential for severe, fatal interstitial lung disease (ILD) associated with leflunomide (LEF) treatment in rheumatoid arthritis (RA) patients.
• Physicians must carefully consider risk factors such as smoking and pre-existing ILD before prescribing LEF.
• Vigilant monitoring for respiratory symptoms during LEF therapy is crucial for early detection and management of potential ILD.