Rheumatoid lung disease is a group of lung conditions that are a complication of rheumatoid arthritis (RA). While RA is known for affecting joints, it is a systemic autoimmune disease that can impact other parts of the body. The immune system mistakenly attacks lung tissues, leading to inflammation and damage. These lung conditions are a serious complication and a major cause of mortality for people with RA.
The Connection Between Rheumatoid Arthritis and the Lungs
The connection between RA and the lungs is systemic inflammation. The same overactive immune response that targets joint linings can also attack lung tissues, such as the interstitium (the tissue supporting the air sacs) and the pleura (the membrane surrounding the lungs).
Several factors increase the risk of lung complications. People with long-standing or severe RA are at higher risk, as are men, particularly those with a history of smoking. The presence of specific antibodies in the blood, like rheumatoid factor (RF) and anti-cyclic citrullinated peptide (anti-CCP), also increases the likelihood of lung problems.
RA medications can also contribute to lung issues. Although rare, some drugs like methotrexate can cause a hypersensitivity reaction. Because many RA treatments suppress the immune system, they also increase susceptibility to respiratory infections that can damage the lungs.
Types of Lung Complications
The most common complication is Interstitial Lung Disease (ILD), involving inflammation and scarring (fibrosis) of the lung’s interstitium. This buildup of scar tissue makes the lungs stiff, impairing their ability to expand and transfer oxygen into the bloodstream. This leads to significant breathing difficulties and affects about one in ten people with RA.
Pleural disease affects the membrane surrounding the lungs. This can manifest as pleurisy, an inflammation causing sharp chest pain, or a pleural effusion, where excess fluid compresses the lung. Both conditions can make it difficult to breathe fully.
Rheumatoid nodules, firm lumps similar to those under the skin, can also develop in the lungs. Often found incidentally on imaging scans, they are usually benign and cause no symptoms. Monitoring may be required to distinguish them from other growths.
RA can also cause airway diseases. Bronchiectasis is a condition where airways permanently widen, making it hard to clear mucus and leading to recurrent infections. A rarer issue is bronchiolitis obliterans, which involves inflammation and blockage of the smallest airways.
Recognizing the Symptoms
Symptoms of rheumatoid lung disease often develop gradually. A primary sign is progressive shortness of breath during physical activity, like climbing stairs. This occurs because lung inflammation or scarring makes it harder for the body to get enough oxygen.
A persistent, dry cough that does not produce phlegm is another indicator. This type of cough lingers for weeks or months and arises from irritation within the lung tissues or airways.
General symptoms of systemic inflammation may also be present, including fatigue, unexplained weight loss, and feeling unwell. Chest pain, especially with deep breaths, can occur if the pleura is inflamed. In some cases, respiratory symptoms appear before the joint-related signs of RA.
Diagnosis and Medical Evaluation
Diagnosis begins with a physical exam, where a physician uses a stethoscope to listen for abnormal lung sounds. The presence of fine, crackling noises, known as rales, can be an early indication of inflammation or fibrosis in the lungs. The doctor will also assess for other signs, like decreased breath sounds.
Imaging tests are a fundamental part of the diagnostic process. While a standard chest X-ray may be used, a High-Resolution Computed Tomography (HRCT) scan is the preferred method. An HRCT provides detailed images that allow doctors to visualize subtle scarring, inflammation, or fluid buildup.
To measure how well the lungs are working, doctors use pulmonary function tests (PFTs). These non-invasive breathing tests assess lung capacity, airflow, and how efficiently oxygen is transferred into the bloodstream. The results help quantify lung damage and monitor disease progression.
In some cases, a bronchoscopy may be necessary to rule out other conditions or confirm a diagnosis. This procedure involves inserting a thin tube with a camera into the airways to inspect them and collect a small tissue sample (biopsy) for examination.
Treatment and Management Approaches
Treatment focuses on managing the underlying RA to control the inflammation driving lung damage. Medications include disease-modifying antirheumatic drugs (DMARDs) and biologics. For direct lung involvement, doctors may prescribe corticosteroids to reduce inflammation or other immunosuppressive drugs. In cases of ILD with fibrosis, specific antifibrotic drugs may slow the scarring process.
Supportive therapies help manage symptoms and improve quality of life. For individuals with low blood oxygen levels, supplemental oxygen therapy may be prescribed. Pulmonary rehabilitation is a program that combines exercise, breathing techniques, and education. Smoking cessation is also strongly advised, as smoking can worsen lung irritation.
For severe, end-stage lung disease that no longer responds to other treatments, lung transplantation may be considered. This major surgery replaces one or both damaged lungs with healthy lungs from a donor. It is reserved as a final option when lung function severely limits daily life and longevity.