Interstitial Lung Disease in Rheumatoid Arthritis: A Practical Review

Abstract

Rheumatoid arthritis (RA) is a systemic inflammatory disease, which primarily causes symmetric polyarthritis. An extrarticolar involvement is common, and the commonly involved organ is lungs. Although cardiac disease is responsible for most RA-related deaths, pulmonary disease is also a major contributor, accounting for ~10-20% of all mortality. Pulmonary disease is a common (60-80% of patients with RA) extra-articular complication of RA. Optimal screening, diagnostic, and treatment strategies of pulmonary disease remain uncertain, which have been the focus of an ongoing investigation. Clinicians should regularly assess patients with RA for the signs and symptoms of pulmonary disease and, reciprocally, consider RA and other connective tissue diseases when evaluating a patient with pulmonary disease of an unknown etiology. RA directly affects all anatomic compartments of the thorax, including the lung parenchyma, large and small airways, pleura, and less commonly vessels. In addition, pulmonary infection and drug-induced lung disease associated with immunosuppressive agents used for the treatment of RA may occur.

Keywords: ILD; IPAF; bronchiectasis; lungs; rheumatoid arthritis.

Figure 1

Lungs as a site for the initiation of rheumatoid arthritis (RA).

Figure 2

Respiratory involvement in RA.

Figure 3

High-resolution computer tomography (HRCT) findings in respiratory diseases and particularly interstitial disease (RA-ILD). (A) An usual interstitial pneumonia (UIP) pattern (representing the most typical radiological presentation in patients with RA) is primarily characterized by reticular fibrosis, traction BR, and subpleural cysts (honeycombing). (B) A nonspecific interstitial pneumonia (NSIP) pattern is primarily characterized by ground-glass opacities, variably mixed with septal thickening, and reticular fibrosis (fibrosing NSIP). (C) A lymphocytic interstitial pneumonia (LIP) pattern is primarily characterized by perivascular thin-walled cysts (black arrows). (D) An organizing pneumonia (OP) pattern is primarily characterized by pulmonary consolidations (a white arrow).

Figure 4

Multiple pulmonary nodules on HRCT in a patient with RA.

Figure 5

Bronchiectasis (BR) on HRCT in a patient with RA.

Figure 6

The proposed algorithm for pulmonary symptoms in RA. ABA, abatacept; bDMARD, biological disease-modifying antirheumatic drug; csDMARD, conventional synthetic disease-modifying antirheumatic drug; ILD, interstitial lung disease; MTX, methotrexate; MTX-pneu, MTX-pneumonitis; RA, rheumatoid arthritis; RTX, rituximab; TCZ, tocilizumab. MIP Methotrexate-induced pneumonia; GCs glucocorticoids.