While known for attacking the joints of the body, rheumatoid arthritis (RA)--a chronic inflammatory disease--can also lead to progressive diseases of the lung. According to the Johns Hopkins Arthritis Center, respiratory conditions rank as the second leading cause of death among those with RA. Some of these conditions are caused or exacerbated by common medical treatments for RA (such as methotrexate), while others are a byproduct of progressive, systemic inflammation.
Interstitial Lung Disease
Interstitial lung disease (ILD) is the general classification for pulmonary conditions characterized by progressive and irreversible scarring of lung tissue. According to the Johns Hopkins Arthritis Center (JHAC), interstitial lung disease is the most common and most serious type of lung condition associated with rheumatoid arthritis. An individual may have ILD for years before developing overt symptoms; however, once symptomatic and clinically detectable, the risk of mortality from the disease rises significantly. According to the Mayo Clinic, symptoms associated with ILD include a feeling of breathlessness, dry cough, wheezing, chest pain and a clubbing of the fingernails.
A study published in a 2008 issue of the "Archives of Internal Medicine" reports that individuals with rheumatoid arthritis who smoke are more likely to have asymptomatic or preclinical interstitial lung disease. Treatment with methotrexate (a very commonly used disease-modifying anti-rheumatic drug, or DMARD) is also identified as a risk factor for progression of ILD.
Pulmonary Fibrosis
Pulmonary fibrosis is a condition in which the air sacs of the lungs are gradually replaced with fibrotic (inflamed and scarred) tissue, causing progressive, irreversible damage and diminished ability to transfer oxygen to the bloodstream. While its exact cause is uncertain, it is known to be associated with rheumatoid arthritis. Common symptoms of pulmonary fibrosis include shortness of breath, dry or hacking cough, fatigue, weakness, chest pain or discomfort, loss of appetite and rapid weight loss, according to The Pulmonary Fibrosis Foundation.
Methotrexate Pneumonitis
Methotrexate pneumonitis is a rare lung condition caused by treatment with the drug methotrexate. Although its symptoms -- such as cough, dyspnea (breathlessness) and fever-- can persist for weeks or months before a diagnosis is made, the condition may quickly lead to acute respiratory failure, according to Patient UK.
Chronic Obstructive Pulmonary Disease (COPD)
Chronic Obstructive Pulmonary Disease (COPD) is a group of lung conditions characterized by impaired air flow and difficulty breathing. According to the Mayo Clinic, the two main conditions that comprise COPD are emphysema and chronic bronchitis. COPD is known to occur more frequently in individuals with RA than in the general population (even after adjusting for rates of smoking which are a known cause of COPD), and it is also likely to have a bigger impact on survival rates among RA patients, according to the JHAC. Symptoms of COPD often do not appear until irreversible damage to the lungs has occurred. Once they appear, they typically include a chronic cough that sometimes produces a yellowish sputum, wheezing, shortness of breath, tightness in the chest and frequent respiratory infections.
References
- Johns Hopkins Arthritis Center: Lung involvement in RA
- "Archives of Internal Medicine;" Progressive preclinical interstitial lung disease in rheumatoid arthritis; Gochuico BR et al.; January 2008
- Pulmonary Fibrosis Foundation: What is Pulmonary Fibrosis
