Lung Diseases and Conditions

Among extra-articular (this literally means “outside of the joints”) manifestations of RA, lung conditions are the most common. A variety of lung diseases and conditions, most involving inflammation, including pleuritis, pulmonary fibrosis, pulmonary rheumatoid nodules, and interstitial lung disease (types of bronchiolitis and pneumonia), can affect patients with RA. These conditions all involve symptoms including shortness of breath, chronic cough, pain, and discomfort during breathing.^1,2

Abnormal airway function is common in patients with RA. Pulmonary function testing may be below normal in up to 38% of patients with RA. In one study, 16% of non-smoking RA patients were found to have some airway obstruction, a rate much higher than that seen in individuals without RA in the general population.^1,2

Lung diseases related to rheumatoid arthritis

Pleuritis

Pleuritis, which can be caused by autoimmune disorders including systemic lupus erythematosus as well as RA, is an inflammation of the lining of the cavity or pleura surrounding the lungs. Every time the lungs expand during inhalation, they rub against the inflamed pleura causing sharp pain. In pleuritis, inflammation causes the lung to fill rapidly with pleural fluid resulting in difficulty breathing and, ultimately, respiratory distress.¹

Pulmonary fibrosis

Pulmonary fibrosis is the formation of fibrous tissue inside the lungs that appears on x-ray as scarring. The formation of scar tissue interferes with the ability of the lung to expand normally upon inhalation and can lead to chest discomfort, shortness of breath, fatigue, weakness, and a chronic cough.^1,2

Interstitial lung disease

One study estimated that about 6% of patients with RA develop some form of interstitial lung disease, a range of conditions that affect the space and tissues surrounding the air sacs (alveoli) in the lungs. Interstitial lung disease associated with RA typically includes interstitial pneumonias and bronchiolitis (inflammation of the small air passages of the lungs called the bronchioles), as well as damage to alveoli. The symptoms of interstitial lung disease include shortness of breath, pain, and difficulty breathing.^1,2

Rheumatoid nodules

The formation of nodules in the lungs occurs in a small minority of patients with RA (less than 1%). RA nodules are more common in men than women. Typically, nodules are asymptomatic. They may form before or after RA has been diagnosed. Additionally, they may increase in size or remain the same size or disappear spontaneously.²

Factors that increase risk for developing lung disease

A number of factors have been linked to increased risk for developing RA-related interstitial lung disease. These include genetic factors (the presence of certain gene variants) that increase susceptibility to lung disease and environmental factors. Smoking, which is a clear risk factor for development of RA, is also a risk factor that increases the chances of developing lung disease in patients with RA.²

Treatment of RA-related lung disease

Glucocorticoid treatment (sometimes used with cytotoxic drugs) is typically used to manage interstitial lung disease associated with RA. While experience with other agents is limited, in cases where interstitial lung disease is resistant to glucocorticoids, treatment with cyclophosphamide, cyclosporine, or azathioprine may be useful.²

Management approaches for pleuritis include glucocorticoid treatment (oral) and drainage of fluid accumulation caused by inflammation.²

Long-term treatment with disease-modifying anti-rheumatic drugs (DMARDs) and/or newer biologics that can address RA inflammation is generally recommended for extra-articular manifestations of RA, including those affecting the lungs.¹