Abstract
Rheumatoid arthritis (RA) is a common chronic systemic autoimmune disease characterized
by joint inflammation and, in a proportion of patients, extra-articular manifestations
(EAM). Lung disease, either as an EAM of the disease, related to the drug therapy
for RA, or related to comorbid conditions, is the second commonest cause of mortality.
All areas of the lung including the pleura, airways, parenchyma, and vasculature may
be involved, with interstitial and pleural disease and infection being the most common
problems. High-resolution computed tomography of the chest forms the basis of investigation
and when combined with clinical information and measures of physiology, a multidisciplinary
team can frequently establish the diagnosis without the need for an invasive biopsy
procedure. The most frequent patterns of interstitial lung disease (ILD) are usual
interstitial pneumonia (UIP) and nonspecific interstitial pneumonia (NSIP), with some
evidence for the prognosis being better than for the idiopathic equivalents. Risk
factors depend on the type of disease but for ILD (mainly UIP and NSIP) include smoking,
male gender, human leukocyte antigen haplotype, rheumatoid factor, and anticitrullinated
protein antibodies (ACPAs). Citrullination of proteins in the lung, frequently thought
to be incited by smoking, and the subsequent development of ACPA appear to play an
important role in the development of lung and possibly joint disease. The biologic
and nonbiological disease modifying antirheumatic drugs (DMARDs) have had a substantial
impact on morbidity and mortality from RA, and although there multiple reports of
drug-related lung toxicity and possible exacerbation of underlying ILD, overall these
reactions are rare and should only preclude the use of DMARDs in a minority of patients.
Common scenarios facing pulmonologists and rheumatologists are addressed using the
current best evidence; these include screening the new patient; monitoring and choosing
RA treatment in the presence of subclinical disease; treating deteriorating ILD; and
establishing a diagnosis in a patient with an acute respiratory presentation.
Keywords
rheumatoid arthritis - lung - interstitial - drug induced - anticitrullinated protein
antibodies - biologic disease modifying antirheumatic drugs - prognosis
