RA and Lung Disease: What You Need to Know
Respiratory problems are one of the most common – and serious – extra-articular complications of rheumatoid arthritis.
Besides the joints, the inflammatory process that underlies rheumatoid arthritis (RA) also affects other parts of the body, including lungs, skin, eyes, digestive system, heart and blood vessels. RA-related lung complications are the most common extra-articular (“outside of the joints”) manifestations of RA and include pulmonary nodules (small growths in the lungs); pleural effusion (a buildup of fluid between the lung and chest wall); bronchiectasis (damage to the airways); and interstitial lung disease (ILD).
In fact, it is estimated that 1 in 10 people with rheumatoid arthritis will develop ILD over the course of their disease, making it as deadly among people with RA as congestive heart failure.
What Is Interstitial Lung Disease?
Interstitial lung disease refers to a group of disorders characterized by inflammation and scarring of the lung tissue. In the case of RA-associated ILD, the scarring is caused when the over-active immune system attacks the lungs. When the scarring builds up over time, breathing becomes difficult, and patients may need lung transplants to regain function.
Risk Factors for Interstitial Lung Disease
The risk of developing lung disease is eight times higher in people with RA than in the general population. However, most people with RA are not affected. Risk factors for ILD include:
- Smoking. People with RA who smoke are more likely to develop ILD.
Higher RA disease activity. High levels of rheumatoid factor (RF) and anti-cyclic citrullinated peptides (antiCCP) antibodies – substances that are indicative of more active disease – increase the risk for development of ILD.
Older age at diagnosis. People who are diagnosed with rheumatoid arthritis after age 60 are more likely to develop ILD.
Male Gender. Men with RA have a two-to-three times higher risk of developing ILD than women.
Treatment with methotrexate and other DMARDs. Several DMARDs, including methotrexate, leflunomide and azathioprine, as well as biologics, particularly tumor necrosis factor (TNF) inhibitors, have been associated with RA-ILD, according to a literature review published in the April 2014 issue of Seminars in Arthritis and Rheumatism. But Dr. Teng Moua, a pulmonologist specializing in ILD at the Mayo Clinic in Rochester, Minn., says the risk of methotrexate-induced lung injury is less than 1 percent and is reversible once the drug is stopped. According to Dr. Moua, the benefits of methotrexate far outweigh its risks. However, methotrexate is not recommended for people with existing ILD or RA-ILD by the American College of Rheumatology in their 2012 guidelines.
Diagnosis of Interstitial Lung Disease
It is challenging to catch ILD early because it doesn’t cause any specific symptoms. Once shortness of breath and dry cough develop, the disease has probably already progressed.
The diagnostic process includes a comprehensive clinical exam, X-rays and lung function tests. If there are risk factors for ILD or abnormal X-ray findings, your doctor will likely perform a high resolution CT.
Treatment of Interstitial Lung Disease
Interstitial lung disease is a progressive disease. It is hard to treat and has a high mortality rate. The type of ILD affects mortality risk. Different factors may affect survival rates including RA disease duration, time of ILD diagnosis and extent of the disease, older age, male gender, smoking behavior and the presence of lung tissue scarring. Early treatment of ILD reduces mortality risk. Treatment options include corticosteroids and immunosuppressants. However, these treatments may not work the same way for everyone, and patients may experience medication side effects. Oxygen therapy may be prescribed and building aerobic fitness can help improve quality of life. In some cases, a lung transplant is an effective option. The best approach is to treat the underlying RA and resulting inflammation, although ILD may get worse despite well controlled arthritis.
Future Direction in Interstitial Lung Disease
Researchers say an important task for the medical community is to understand the mechanisms behind the development of ILD in people with RA. More detailed knowledge of these processes may one day open doors to better treatments.
Also needed are comprehensive guidelines for screening and diagnosing ILD in at-risk patients so they can be found and treated earlier.
How Can You Protect Your Lungs?
Don’t smoke. Get flu and pneumonia vaccines (but always check with your doctor before getting any vaccinations). If you’re taking immunosuppressant medications for your RA, you may be at a higher risk for illnesses like the flu and pneumonia, which may cause further lung-related complications. Have regular check-ups, so your doctor can monitor your lungs regularly. Tell your doctor if you have shortness of breath or dry cough right away.
Updated May 2015