Rheumatoid lung disease is a disease of the lung associated with RA, rheumatoid arthritis. Rheumatoid lung disease is characterized by pleural effusion, pulmonary fibrosis, lung nodules and pulmonary hypertension. Common symptoms associated with the disease include shortness of breath, cough, chest pain and fever. It is estimated that about one quarter of people with rheumatoid arthritis develop this disease, which are more likely to develop among elderly men with a history of smoking.Rheumatoid lung is separate from but often associated with Interstitial lung disease(ILD). Signs and symptoms
Most common:

Chest Pain
Cough
Fever
Shortness of breath
Joint pain, stiffness, swelling
Skin nodulesPeople may not present with all these symptoms or none at all. From most to least common:

Pleural involvement (pleurisy, effusions)
Pulmonary parenchymal nodules, more common in men than in women
Rheumatoid-associated interstitial lung disease
Bronchiolitis obliterans organizing pneumonia
Obliterative bronchiolitis (obstructive lung disease/bronchiectasis)
Rheumatoid-associated pulmonary hypertension
Pulmonary vasculitis/arteritis
Shrinking lung syndrome
Miscellaneous: MTX, cricoarytenoid arthritis, infection, cancer

Causes
The exact cause of rheumatoid lung disease is unknown. However, associated factors could be due largely to smoking. Sometimes, the medicines used to treat rheumatoid arthritis, especially methotrexate, may result in lung disease.Prevention:

Stop smoking: Chemicals found in cigarettes can irritate already delicate lung tissue, leading to further complications. Having regular checkups: The doctor could listen to lungs and monitor breathing, because lung problems that are detected early can be easier to treat. Mechanism
RA is a complex and poorly understood disease. However, the characteristic presence of antibodies to citrullinated proteins (anti-CCP) suggests that there are pathogenic mechanisms unique to RA. Recent studies suggest a link between smoking, HLA-DRBSE, anti-CCP and RA.
In that study of 550 RA patients, logistic regression analysis of data collected on the 237 (43%) with ILD revealed that age, smoking, RF positivity, and elevated lactate dehydrogenase closely correlated with ILD.Recent studies have identified risk factors for disease progression and mortality. A retrospective study of 167 patients with RA-ILD determined that the usual interstitial pneumonia (UIP) pattern on high-resolution computed tomography (HRCT) was a risk factor for progression, as were severe disease upon diagnosis and rate of change in pulmonary function test results in the first 6 months after diagnosis. A study of 59 RA-ILD patients found no median survival difference between those with the UIP pattern and those without it. But the UIP group had more deaths, hospital admissions, need for supplemental oxygen, and decline in lung function. == References ==