ABSTRACT
Interstitial lung disease (ILD) often arises within the context of an underlying connective tissue disease (CTD) and is often associated with significant morbidity and mortality (1). The CTDs are a group of systemic autoimmune disorders with significant clinical heterogeneity characterized by immune-mediated organ dysfunction (Table 14.1), and the lung is a frequent target. All CTD patients are at risk for developing ILD, and those with systemic sclerosis (SSc), poly-/dermatomyositis (PM/DM) and rheumatoid arthritis (RA) are at particularly high risk. ILD may develop at any point in the natural history of CTD, is most frequently identified within the context of an established CTD and may also be the first clinically apparent manifestation of occult CTD (2–4). Furthermore, some individuals may have ‘interstitial pneumonia with autoimmune features’ (IPAF), defined by the presence of ILD and features suggestive of (but not diagnostic for) underlying CTD (5). Determining whether a patient has a diagnosis of CTD-associated ILD (CTD-ILD) is important, as this knowledge may impact treatment decisions, can guide surveillance for other concomitant clinical features and can help with prognostication (1).
