Interstitial lung disease in undifferentiated forms of connective tissue disease.

Abstract

The intersection of interstitial lung disease (ILD) and connective tissue disease (CTD) is complex and commonly includes the scenario whereby ILD is identified in patients with pre-existing, well-characterized forms of CTD, is the presenting manifestation of a well-characterized form of CTD, or arises within the context of a poorly defined, “undifferentiated” form of CTD. Determining that an ILD is CTD associated is important because this knowledge often impacts management and prognosis. Identifying occult CTD in patients with an “idiopathic” ILD can be challenging and requires a comprehensive, often multidisciplinary, evaluation. There is much uncertainty and controversy surrounding undifferentiated forms of CTD-associated ILD and prospective studies are needed to provide a better understanding of the natural history of these cohorts, how to best manage them, and to determine whether they behave similar to definite forms of CTD-associated ILD.