Respiratory diseases
Rheumatoid nodules can occur in the lung below its lining and cause no symptoms. They are usually discovered accidentally in chest x-rays performed for other reasons. They appear as multiple lumps, and they can be mistakenly diagnosed as cancer. Rheumatoid arthritis does not cause nodules only; It can also cause a dangerous condition called pleural effusion. Pleural effusion is an accumulation of fluid inside the lung that can cause breathing difficulties. This condition affects 30% of rheumatoid arthritis patients.