Rheumatoid arthritis (RA) interstitial lung disease

• rheumatoid arthritis interstitial lung disease (RA-ILD) is increasingly recognised and is clinically significant in up to 5% of patients with RA (1)
  
  
• RA-ILD is strongly associated with male gender, a history of smoking and seropositivity. Although considered a complication of RA, lung disease may predate or develop at the same time as synovitis
  
  
• usual interstitial pneumonia and non-specific interstitial pneumonia are the two most common patterns (2)
  
  
• full assessment of RA-ILD requires clinical awareness, chest examination, pulmonary function testing and high resolution computed tomography (HRCT) of the thorax, which will confirm the diagnosis and allow assessment of subtype and disease extent
  
  
• treatment for RA-ILD typically involves the use of high-dose corticosteroids, often in conjunction with alternative immunosuppressant agents such as azathioprine or mycophenolate mofetil, and outcomes vary widely depending on the initial pattern of lung disease (2)
  • other agents such as cyclophosphamide and rituximab also offer promise in the treatment of RA-ILD (1)
    
    
• prognosis (1)
  • prognosis of patients with RA-ILD has been the subject of several studies in the last 20 years with most papers concluding that the mean survival from diagnosis is about 3 years
    • however, unpublished data suggest survival may have improved over the last 10 years to around 4 years
    • pattern of ILD can be determined by HRCT, and appears to be one major determinant of prognosis
      • with usual interstitial pneumonia (UIP) carrying the worst outlook and those with non-specific interstitial pneumonia (NSIP), cryptogenic organising pneumonia (COP) and overlap syndromes (OS) faring rather better
      • data suggest HRCT assessment of disease extent also predicts survival with extensive disease defined as >20% of lung affected on HRCT

Reference:

• ARC (Summer 2013). Topical Reviews - Interstitial lung disease in rheumatoid arthritis: a review.
• Hallowell RW, Horton MR. Interstitial Lung Disease in Patients with Rheumatoid Arthritis: Spontaneous and Drug Induced. Drugs. 2014