Reactive Arthritis Symptoms
Pain can also occur in the knee from diseases or conditions that involve the knee joint, the soft tissues and bones surrounding the knee, or the nerves that supply sensation to the knee area. In fact, the knee joint is one of the most commonly involved joints in rheumatic diseases, including rheumatoid arthritis, reactive arthritis, systemic lupus erythematosus, as well as osteoarthritis.
Reactive arthritis facts
- Reactive arthritis involves inflammation of joints due to an infection in another part of your body. The most common triggers are the genital, urinary, or gastrointestinal systems.
- Reactive arthritis can occur after genital (venereal) infection or bowel infection (dysentery).
- Reactive arthritis shares many features with psoriatic arthritis, ankylosing spondylitis, and the arthritis of Crohn's disease and ulcerative colitis.
- Reactive arthritis can affect the joints, the spine, the eyes, urinary tract, mouth, colon, and heart.
- There is no single laboratory test for diagnosing reactive arthritis. The HLA-B27 genetic marker is commonly found in the blood.
- Treatment of reactive arthritis is directed toward the specific body area(s) inflamed or affected.
What is reactive arthritis?
Reactive arthritis is a chronic form of arthritis featuring the following three conditions: (1) inflamed joints, (2) inflammation of the eyes (conjunctivitis), and (3) inflammation of the genital, urinary, or gastrointestinal systems.
This form of joint inflammation is called "reactive arthritis" because it is felt to involve an immune system that is "reacting" to the presence of bacterial infections in the genital, urinary, or gastrointestinal systems. Accordingly, certain people's immune systems are genetically primed to react aberrantly when these areas are exposed to certain bacteria. The aberrant reaction of the immune system leads to spontaneous inflammation in the joints and eyes. This can be confounding to the patient and the doctor when the infection has long passed at the time of presentation with arthritis or eye inflammation.
Reactive arthritis has, in the past, been referred to as Reiter's syndrome (a term that has lost favor because of Dr. Hans Reiter's dubious past, one of enthusiastically embracing Nazi politics and medical abominations). In addition, Reiter's syndrome would refer to a specific type of reactive arthritis limiting inflammation to the eyes, urethra, and joints.
Reactive arthritis most frequently occurs in patients in their 30s or 40s, but it can occur at any age. The form of reactive arthritis that occurs after genital infection (venereal) occurs more frequently in males. The form that develops after bowel infection (dysentery) occurs in equal frequency in males and females.
Reactive arthritis is considered a systemic rheumatic disease. This means it can affect other organs than the joints, causing inflammation in tissues such as the eyes, mouth, skin, kidneys, heart, and lungs. Reactive arthritis shares many features with several other arthritic conditions, such as psoriatic arthritis, ankylosing spondylitis, and arthritis associated with Crohn's disease and ulcerative colitis. Each of these arthritic conditions can cause similar disease and inflammation in the spine and other joints, eyes, skin, mouth, and various organs. In view of their similarities and tendency to inflame the spine, these conditions are collectively referred to as "spondyloarthropathies."
What causes reactive arthritis?
As mentioned, reactive arthritis is felt in part to be genetic. There are certain genetic markers that are far more frequent in patients with reactive arthritis than in the normal population. For example, the HLA-B27 gene is commonly seen in patients with reactive arthritis. Even in patients who have the genetic background that predisposes them to developing reactive arthritis, however, exposure to certain infections seems to be required to trigger the onset of the disease.
Reactive arthritis can occur after venereal infections. The most common bacterium that has been associated with this post-venereal form of reactive arthritis is an organism called Chlamydia trachomatis. Reactive arthritis also occurs after infectious dysentery, with bacterial organisms in the bowel, such as Salmonella, Shigella, Yersinia, Campylobacter, and Clostridium difficile. Typically, the arthritis develops one to three weeks after the onset of the bacterial infection. Reactive arthritis has also been reported associated with bladder infusions of BCG used for treating bladder cancer.
What are risk factors for developing reactive arthritis?
- Gender: Reactive arthritis is more frequent in men.
- Age: It is most frequent in people between 20 and 40 years of age.
- Hereditary factors: There are inherited genes, such as HLA-B27, that increase the risk for developing reactive arthritis.
Medically Reviewed by a Doctor on 12/2/2015