Reactive arthritis (ReA) is an autoimmune condition that develops in response to an infection in another part of the body. Coming into contact with bacteria and developing an infection can trigger reactive arthritis. It has symptoms similar to various other conditions collectively known as "arthritis," such as rheumatism. It is caused by another infection and is thus "reactive", i.e., dependent on the other condition. The "trigger" infection has often been cured or is in remission in chronic cases, thus making determination of the initial cause difficult.
The symptoms of reactive arthritis very often include a combination of three seemingly unlinked symptoms—an inflammatory arthritis of large joints, inflammation of the eyes (conjunctivitis and uveitis), and urethritis. A useful mnemonic is "the patient can't see, can't pee and can't bend the knee". Formerly known as Reiter’s syndrome, after German physician Hans Reiter, it is also known as arthritis urethritica, venereal arthritis and polyarteritis enterica. It is a type of seronegative spondyloarthropathy.
Reactive arthritis is an RF-seronegative, HLA-B27-linked spondyloarthropathy (autoimmune damage to the cartilages of joints) often precipitated by genitourinary or gastrointestinal infections, some of which can be transmitted through sexual activities.
It most commonly strikes individuals aged 20-40, is more common in men than in women, and is more common in white men than in black men. This is owing to white individuals' being more likely to have tissue type HLA-B27 than black individuals. People with HIV have an increased risk of developing reactive arthritis as well. Food poisoning is a common cause.
The classical presentation is that the first symptom experienced is a urinary symptom such as burning pain on urination (dysuria) or an increased need for or frequency) of urination (polyuria. Other urogenital problems may arise such as prostatitis in men, and cervicitis, salpingitis and/or vulvovaginitis in women.
Eye involvement occurs in about 50% of men with urogenital reactive arthritis and about 75% of men with enteric reactive arthritis. Conjunctivitis and uveitis can include redness of the eyes, eye pain and irritation, or blurred vision. Eye involvement typically occurs early in the course of reactive arthritis, and symptoms may come and go.
Roughly 20 to 40 percent of men with reactive arthritis develop penile lesions called balanitis circinata (circinate balanitis) on the end of the penis. A small percentage of men and women develop small hard nodules called keratoderma blennorrhagica on the soles of the feet, and less often on the palms of the hands or elsewhere. In addition, some people with Reactive Arthritis develop mouth ulcers that come and go. In some cases, these ulcers are painless and go unnoticed. Some people suffer serious gastrointestinal problems similar to those of Crohn's Disease.
Commonly remembered with the mnemonic "Can't See, Can't Pee, Can't Climb a Tree". Alternatively, the final letters of Jack KeroUAC's name (a "Reiter") are an acronym for urethritis, arthritis and conjunctivitis.
The urethra, cervix and throat may be swabbed in an attempt to culture the causative organisms. Cultures may be carried out on urine and stool samples. Synovial fluid from an affected knee may be aspirated to look at the fluid under the microscope and for culture.
Also, a blood test for the gene HLA-B27 may be given to determine if the patient has the gene. About 75 percent of all patients with Reiter's Syndrome have the gene.