Rheumatoid Arthritis Interstitial Lung Disease

Rheumatoid arthritis (RA) is a systemic, autoimmune, inflammatory disorder affecting 0.51% of the North American population (Gabriel, 2001). It has a predilection for young women with an incidence rate of up to 130 per 100,000 compared with 70 per 100,000 in men [Minaur et al, 2004]. It is associated with a median survival decrease of up to 11 years compared to the general population (Minaur et al., 2004). The disease course may be complicated by extra-articular manifestations that confer an added burden of morbidity and mortality. RA-associated cardiovascular and infectious complications are commonly highlighted as major causes of morbidity and mortality in these patients (Maradit-Kremers et al., 2005). However, pulmonary involvement, the third leading extra-articular manifestation of RA, is now also recognized as a major cause of morbidity and mortality in RA patients. This was demonstrated in an autopsy study of 81 RA patients where the cause of death was determined to be infectious in 23.5%, cardiovascular in 17.3% and respiratory in 9.9% of patients (Suzuki et al., 1994). Pulmonary complications are the presenting manifestation of RA in up to 20% of patients (Brown, 2007). These complications include airway disease, pleural effusion, pulmonary nodules, and interstitial lung disease (ILD). This chapter will discuss the epidemiology, clinical features, management of RA-associated ILD (RA-ILD) and highlight the links between pulmonary involvement and autoimmunity.