Investigation of Lung Involvement in Connective Tissue Disorders

Lung involvement in connective tissue disorders (CTDs) may present as pleomorphic since any lung compartment may be involved such as airways, exocrine secretory and alveolar epithelia, interstitial lung structure, pulmonary vasculature and pleura as well as, in specific disorders, several tissues of the thoracoabdominal ventilator pump. Any combination of the above anatomic structures may be involved concomitantly although some specific combinations may include a determinant of rheumatic disorders. The diagnosis of a specific CTD requires the fulfilment of clearly defined clinical and laboratory criteria including in most cases positivity for autoantibodies, mostly specific serologic combinations. In this setting, serologic investigation targets mainly, although not exclusively, the detection of antinuclear antibodies. A specific serologic positivity or a combination of autoantibodies constitutes not only a diagnostic criterion for a specific CTD, but may also characterize the pattern of respiratory manifestation in a determinant rheumatic disorder. Therefore, the investigation of lung involvement in CTDs requires adequate skills in the ambit of a multidisciplinary approach and an extended spectrum of diagnostic tools and modalities able to detect both early clinical clues and serologic conversion as well as any pathophysiologic alteration that regards the complexity of respiratory functional status. Although many patients with CTDs suffer from a 'vicious' combination of lung involvement, lung drug toxicity and infections related to the above two as well as to the 'mater' disease, for space reasons this review will focus on the established lung manifestations that regard the 7 major CTDs.