Reactive arthritis (Reiter syndrome)

What it is

Reactive arthritis, also called Reiter syndrome, is an asymmetrical oligoarthritis of the lower extremities.

Causes and risk

It is proceeded by one of four: Salmonella, Shigella, Campylobacter and Yersinia. The other door is the urethra, since the triad itself opens with urethritis or cervicitis.

The triad, and the order inside it

The classic triad is asymmetrical arthritis, urethritis or cervicitis or diarrhoea, and conjunctivitis.

It is put as cannot see, cannot pee, cannot climb a tree: pee is urethritis, see is uveitis, climb a tree is arthritis.

The order inside the triad matters as much as the list: conjunctivitis is seen frequently after the onset of urethritis, so the eye follows the urethra rather than opening with it.

The joint, and how it differs from early rheumatoid arthritis

Joint involvement is usually asymmetric and involves multiple joints. It resembles the early stage of rheumatoid arthritis, and that is the trap. What separates them is what is found in the joint: loose fibrinoid exudate with fibrous bands in joint, but no villi and no joint damage. Rheumatoid arthritis is the one that damages the joint.