The usual Interstitial pneumonia pattern in autoimmune rheumatic diseases

Usual Interstitial Pneumonia (UIP) is characterized by progression of lung parenchyma that may be observed in various autoimmune rheumatic diseases (ARDs), including rheumatoid arthritis and connective tissue diseases. From a diagnostic point of view, a UIP pattern related to ARDs may display imaging and pathological features able to distinguish it from that related to IPF, such as the straight-edge sign at HRCT and lymphoplasmacytic infiltrates at histologic specimens. Multidisciplinary approach (MDD), involving at least pulmonologist, rheumatologist and radiologist, is fundamental in the differential diagnosis process, but MDD is also required in the evaluation of severity, progression and response to treatment, that is based on the combination of changes in symptoms, pulmonary function trends, and, in selected patients, serial CT evaluation. Differently from IPF, in patients with ARDs both functional evaluation and patient-reported outcomes may be affected by systemic involvement and comorbidities, including musculoskeletal manifestations of disease. Finally, in regards to pharmacological treatment, immunosuppressants have been considered the cornerstone of therapy, despite the lack of solid evidence in most cases; recently, antifibrotic drugs were also proposed for the treatment of progressive fibrosing ILDs other than IPF. In ARD-ILD, the therapeutic choice should balance the need for the control of systemic and lung involvements with the risk of adverse events from multi-morbidities and -therapies. Purpose of this review is to summarize the definition, the radiological and morphological features of the UIP pattern in ARDs, together with risk factors, diagnostic criteria, prognostic evaluation, monitoring and management approaches of the UIP-ARDs.

Automated summary

Usual Interstitial Pneumonia (UIP) can occur in various autoimmune rheumatic diseases (ARDs), such as rheumatoid arthritis. The imaging and pathological features can differentiate it from UIP related to IPF. A multidisciplinary approach is crucial in the differential diagnosis and evaluation of severity, progression, and treatment response. In ARD patients, functional evaluation and patient-reported outcomes may be influenced by systemic involvement and comorbidities. Immunosuppressants are considered the main therapy, although evidence is lacking in most cases; recently, antifibrotic drugs have also been proposed for progressive fibrosing ILDs other than IPF. This review summarizes the definition, features, risk factors, diagnostic criteria, prognostic evaluation, monitoring, and management approaches of UIP-ARDs.