Rheumatoid Lung

• Although rheumatoid arthritis is more common in females, extra-articular manifestations of the disease are more common in males

• Almost all patients with pulmonary evidence of RA have:

• Clinical evidence of the disease

• Severe disease

• Circulating antibody is largely IgM in patients with RA and the changes in the lung are probably immune in origin

Pleural Effusion  

• The most common manifestation of RA in the chest

• Pleural fluid is an exudate with a high protein and a very low sugar content (below 30 mg per 100 ml) which does not rise with the IV administration of glucose which the low sugar effusion in TB will do.

• Pleural fluid in RA is also high in LDH, rich in lymphocytes, positive for Rheumatoid Factor, and contains low complement levels.

• The effusion may remain unchanged for months or years

• Most are unilateral but they can occur on either side

• The effusion is almost never associated with parenchymal disease

Pulmonary Fibrosis  

• Begins as micronodular and progresses to coarse reticulation, often more prominent at the bases and indistinguishable from scleroderma

• Has a honeycomb appearance

• Clinically, shortness of breath is most common symptom

• Subcutaneous rheumatoid nodules are often present

• PFTs show restrictive disease

Necrobiotic Nodules  

• Relatively rare

• Almost always associated with subcutaneous nodules and identical pathologically to them

• Usually well circumscribed masses

• Typically multiple

• Subpleural in location

• With cavitation

• Frequently at bases

Caplan’s Syndrome  

• Necrobiotic nodules with silicosis

• Pathologically, the only difference is a ring of dust in the nodule which produces a darkened ring around the central core

• Roentgenographically identical to rheumatoid nodules with RA

Rheumatoid Disease with Pulmonary Arterial Hypertension  

• Due to an arteritis which produces PAH and eventual cor pulmonale

Obliterative Bronchiolitis  

• Same as BOOP except the patients have RA