Rheumatoid arthritis is an inflammatory disease that primarily affects the body's joints. However, it may also have significant effects on the lungs. Chronic inflammation can lead to scarring of lung tissue, swelling of the tissue lining the lungs, constriction of arteries that feed blood to the lungs, airway restriction and pulmonary fluid buildup. Though some of these effects are treatable, others can cause irreversible damage.
Scarring of Lung Tissue
Rheumatoid arthritis can lead to scarring of lung tissue and a group of conditions referred to as interstitial lung disease (ILD) that make breathing difficult and prevent sufficient oxygen from reaching the bloodstream. It's estimated that clinical significant ILD occurs in about 3 percent to 5 percent of RA patients. Interstitial lung disease can cause dyspnea (breathlessness), dry cough, wheezing, chest pain and clubbed fingernails (nails that curl over the ends of the fingers). Scarring is usually irreversible, and symptoms are typically progressive.
Scarring can also occur in the connective tissue of the alveoli (air sacs) of the lungs, causing a condition called pulmonary fibrosis. Pulmonary fibrosis leads to symptoms such as chronic dry cough, shortness of breath, fatigue, weakness, loss of appetite and rapid weight loss.
Some arthritis medications can also lead to scarring of the small airways in the lungs (bronchiolitis obliterans), leading to shortness of breath or other breathing problems.
Rheumatoid Nodules
People with RA may develop rheumatoid nodules, or lumps that most commonly appear beneath the skin's surface near affected joints. However, they can also develop in the lungs. Pulmonary nodules are rare, with a reported incidence of less than 1 percent based on a chest X-ray. Although most people experience no symptoms, cough, chest pain and hemoptysis (coughing up blood) may occur.
Pleural Effusion
Pleural effusion, or fluid in the lungs caused by inflammation, is the most common problem caused by rheumatoid arthritis. Between 38 percent and 73 percent of people with RA show signs of pleural effusion at the time of death. This condition may cause no symptoms but can cause sharp pain while breathing, fever or shortness of breath.
Airway Complications
Rheumatoid arthritis can lead to a number of airway complications. Upper airway obstruction may occur if pulmonary nodules form on the larynx, or if arthritis develops in the cricoarytenoid joint at the back of the larynx. Bronchiectasis, a condition in which the airways dilate and become scarred, may occur in as many as 10 percent of RA patients. This condition damages the airways by making them more susceptible to infection. Bronchiolitis--an infection of the lung's airways that causes coughing and wheezing--may also occur.
Other Complications
Rheumatoid arthritis can lead to other serious lung complications. One of them is pulmonary hypertension, caused by high blood pressure in the arteries that supply the lungs. When this occurs, blood vessels constrict and the lungs don't get enough oxygenated blood. This results in dizziness, shortness of breath and fatigue.
Another rare complication that can occur secondary to RA is pneumothorax, or a collapsed lung. Sharp chest pain, shortness of breath, rapid heart rate, fatigue and chest tightness may coincide with the onset of this condition.
