M05-M14: Inflammatory polyarthropathies

M05: Seropositive rheumatoid arthritis

Seropositive rheumatoid arthritis (RA) is a chronic inflammatory disorder that primarily affects joints. It belongs to a group of conditions known as autoimmune diseases. In these conditions, the body's immune system mistakenly attacks its tissues, causing damaging inflammation. In the case of seropositive RA, the immune system attacks the lining of the joints causing swelling, pain, and stiffness, which over time may result in joint deformity and bone erosion. It is called "seropositive" because a blood test reveals the presence of specific proteins, known as "rheumatoid factors", which are typically associated with a more severe disease course. Seropositive RA is unpredictable and may fluctuate in severity, with periods of increased disease activity called 'flares', interchanged with periods when symptoms decrease or disappear, called 'remissions'. It's not a contagious condition; its exact cause is still unknown, but it is believed to involve a combination of genetic and environmental factors.