What Is Rheumatoid Lung Disease?

The group of pulmonary issues collectively defined as rheumatoid lung disease are, as the name suggests, the result of rheumatoid arthritis (RA). Lung damage is common in RA, with more than half of patients having some abnormal lung function. About one in 10 will develop rheumatoid lung disease, which can involve airway blockage, fluid in the chest, lung scarring, and other concerns.

Rheumatoid lung disease worsens with time and the lung damage it causes is irreversible, so addressing the condition's symptoms and slowing its progression are critical.

Types of Rheumatoid Lung Disease

The most common manifestation of pulmonary disease in rheumatoid arthritis is interstitial lung disease (ILD), a condition that causes inflammation and scarring (fibrosis) of the lungs. Once lung tissue scars, it no longer functions.

The most frequent forms of interstitial lung disease are usually interstitial pneumonia and nonspecific interstitial pneumonia. Another presentation combines pulmonary fibrosis and emphysema.

Rheumatoid Lung Disease Symptoms

Typical RA symptoms include pain, swelling, and stiffness in the joints. Rheumatoid lung disease has specific additional symptoms that include:

• Shortness of breath (the most common symptom)
• Cough
• Chest pain
• Fever
• Crackle sounds when listening to lungs with a stethoscope; decreased breath sounds or normal breath sounds are also possible

The thoracic and pulmonary abnormalities associated with rheumatoid lung disease include:

• Pulmonary hypertension, high blood pressure in the lungs' blood vessels
• Pulmonary fibrosis, scarring of lung tissue
• Pleural effusion, or "water on the lungs"
• Pleural thickening, scarring of the lungs' lining
• Necrobiotic nodules, abnormal lumps within the lung
• Bronchiectasis, thickening of the bronchial walls
• Bronchiolitis obliterans, inflammatory obstruction of the bronchioles, the lungs' tiniest airways
• Bronchiolitis obliterans organizing pneumonia, a separate type of disease than ILD

Causes

The inflammation and scarring in rheumatoid lung disease comes from the body's immune system attacking the lungs, just as it is attacking the joints in RA itself.

Other risk factors:

• Severe RA: The more active your RA, the greater your chances of developing lung problems.
• Smoking, which is also a known risk factor of rheumatoid arthritis
• Age: People diagnosed with RA after age 60 have a higher chance of developing lung disease.
• Sex: Men have a two- to three-times higher risk of rheumatoid lung disease than women.

It also has been suggested that rheumatoid arthritis medications may possibly lead to drug-induced interstitial lung disease in some cases.

Methotrexate is the gold standard treatment for rheumatoid arthritis. However, methotrexate has also been suggested as a causative agent in interstitial lung disease.

Researchers evaluated the relative risk of pulmonary disease among rheumatoid arthritis patients who were treated with methotrexate. A study concluded there is a small but significant increase in the risk of lung disease in rheumatoid arthritis patients treated with methotrexate compared with other disease-modifying anti-rheumatic drugs (DMARDs) and biologic drugs.

Another study evaluated the relative risk of pulmonary disease among rheumatoid arthritis patients treated with Arava (leflunomide). No evidence of increased respiratory adverse events was found in randomized, controlled trials of rheumatoid arthritis patients treated with leflunomide.

Diagnosis

RA combined with ILD symptoms are enough for a doctor to begin diagnostic testing, but it's critical for patients to seek help as early as possible.

Advancements in computer-assisted image analysis have made it possible to diagnose rheumatoid lung disease earlier and treat it aggressively as a disease of the immune system.

Also, certain blood tests may help reveal ILD. Research has shown that the increased presence of a series of blood biomarkers (matrix metalloproteinase 7, pulmonary and activation-regulated chemokine, and surfactant protein D) in RA patients may help indicate ILD.

Other procedures used to help diagnose the condition include:

• Physical examination (listening to lungs)
• Lung function tests
• Chest X-rays
• Computed tomography (CT) scan of the chest
• Echocardiogram
• Thoracentesis
• Bronchoscopy

Treatment

Treatment for rheumatoid lung disease focuses on slowing the condition's progression, reducing symptoms, and improving quality of life.

The following treatments may be effective to those ends:

• More aggressive RA treatment to help reduce symptoms
• Corticosteroids and immunosuppressants to combat inflammation
• Oxygen therapy to aid lung function and increase blood oxygen levels
• Pulmonary rehabilitation: Education and exercises designed to improve lung function and endurance

Prognosis

While it is possible to have good quality of life with rheumatoid lung disease, it is a serious condition that shortens RA patients' lifespans.

Early and effective treatment is critical. Patients with untreated ILD have a median survival rate of only three years.

For patients with ongoing consistent treatment, the disease may stabilize or slow its progression. In one five-year study, healthcare use and costs were mostly stable over time. In that group, hospitalization rates for the condition (including ER visits) were 14% to 20% each year.

The median survival rate in that group was 7.8 years post-diagnosis.

A Word From Verywell

It's important for all rheumatoid arthritis patients to be vigilant for signs of lung damage, particularly those in higher risk groups like men, older patients, and those with severe RA symptoms. Early detection and proper management of rheumatoid lung disease will help determine quality and length of life going forward.