Acute Pulmonary Infiltrates in Patients with Rheumatoid Arthritis: Differential Diagnosis and Management

Abstract

Patients with rheumatoid arthritis (RA) sometimes experience acute onset of respiratory symptoms with pulmonary infiltrates on chest roentgenogram, potentially leading to respiratory failure. Because many of RA patients have pre-existing lung complications, such as interstitial lung disease (ILD) and airway disease, and receive various immune-modulating drugs, it is often difficult to make a correct diagnosis. The differential diagnosis includes acute exacerbation of RA-associated ILD, drug-induced occurrence or exacerbation of ILD, and respiratory infection. There are many diagnostic tools, such as radiological examination, laboratory tests, bronchoalveolar lavage, and lung biopsy, but, in most cases, none of these tools has enough power to make a diagnosis by itself, requiring a combined diagnostic approach. Once an RA patient is diagnosed with acute exacerbation of ILD or rapidly progressive ILD, ventilatory management and drug treatment should be initiated immediately in accordance with those of acute exacerbation of idiopathic interstitial pneumonias. In case of bacterial pneumonia in RA patients receiving immune-modulating agents, it should be treated as healthcare-associated pneumonia, considering risk factor for Pseudomonas aeruginosa infection. Pneumocystis jirovecii pneumonia in RA patients is characterized by an abrupt onset of respiratory insufficiency, requiring a speedy diagnosis using PCR and serum β-D-glucan measurement.