The exact mechanisms that lead to reactive arthritis (ICD code: M02) are still unclear.
Researchers have now identified certain bacteria in the synovial fluid or synovial membrane of patients with reactive arthritis. It is therefore assumed that pathogens that no longer multiply or pathogen components remain in the joint and cause inflammation there as "foreign substances".
A certain host factor, the so-called HLA-B27, plays an important role in this. It is detectable in 65 to 97 percent of patients with reactive arthritis. People with HLA-B27 in their blood have a five-fold higher risk of developing reactive arthritis than HLA-B27-negative people.
This congenital tissue characteristic influences the immune response and contributes to the development of reactive arthritis.
The video shows the development of arthritis with the destruction of cartilage and bone in the knee joint:
Reactive arthritis is common worldwide. In Germany, the incidence is at least 0.05 percent, i.e. 50 out of every 100,000 inhabitants suffer from reactive arthritis.
Men and women are affected about equally often. The majority of patients are under 40 years of age.
Reactive arthritis usually occurs a few days to weeks after the triggering infection. Typical symptoms of such infections can include
- Burning when urinating,
- frequent urination,
- burning and discharge from the urethra or vagina,
- Diarrheal diseases,
- sore throat or cough
can be. However, these infections can be very mild and are not always noticeable.
Joint complaints as the main symptom
The main symptom of the disease itself is joint pain. The symptoms can vary from mild joint pain (arthralgia) to severe joint inflammation (arthritis). Arthritis is present when, in addition to joint pain, there is also joint swelling and overheating.
The large joints of the lower extremities are usually affected, i.e.
The shoulder, elbow or wrist joints are rarely affected. Only in exceptional cases are small joints (finger and ankle joints) involved.
Generally, only one or a few joints are affected, usually a knee or ankle joint. It is rare for several joints to be inflamed at the same time. Sometimes the inflammation "jumps" from one joint to another.
A so-called polyarthritis, i.e. an attack on many joints at the same time, as in other rheumatic diseases, is very rare.
The large joints of the lower extremities are usually affected by reactive arthritis © freshidea / Fotolia
Other symptoms
In later stages of the disease, deep-seated low back pain may also occur. This indicates inflammation of the sacroiliac joints (SIJs).
Other typical symptoms are inflammation in the area of
- tendon insertions (e.g. the Achilles tendon),
- tendons or
- tendon sheaths.
Sometimes an entire finger or toe is swollen. This is referred to as a "sausage finger" or "sausage toe". Muscle pain can also occur.
Symptoms can also occur on the skin and mucous membranes, e.g. scaly skin changes. These appear particularly on the soles of the hands and feet and are reminiscent of psoriasis.
Occasionally, painful, reddish-bluish lumps are present in the area of the ankles and lower legs(erythema nodosum).
Reactive arthritis can be associated with
can be combined.
In the course of reactive arthritis, inflammation of the eyes can occur, such as
Characteristic symptoms are then
- photophobia,
- pain,
- burning sensation,
- redness and
- possibly visual disturbances.
Reiter's syndrome is a special form of reactive arthritis. This is the simultaneous occurrence of inflammation of the joints, urethra and conjunctiva.
If a young adult has inflammation of one or a few large joints, reactive arthritis may be present.
The doctor will ask the patient about their medical history. It is important to know, for example, whether in the last few days or weeks
- an inflammation of the bladder or urethra,
- a diarrheal illness or
- a respiratory infection
has occurred. If this is the case, the diagnosis can be made relatively quickly. However, some infections may have occurred unnoticed.
Another important clue in the diagnosis of reactive arthritis is the detection of antib odies against the causative pathogen. During an infection, the organism produces antibodies, which are usually detectable in the blood.
Various test systems are therefore used to determine antibodies against possible pathogens that trigger reactive arthritis.
In addition, the HLA-B27 markerand general inflammatory values such as the erythrocyte sedimentation rate, the so-called C-reactive protein (CRP), are determined.
Ultrasound and X-ray examinations of the affected joints can be used to determine the extent of the inflammation.
The symptoms can vary from mild joint pain to severe joint inflammation. The therapy must therefore be adapted to the respective symptoms.
The main drugs used for drug therapy are so-called cortisone-free anti-rheumatic drugs such as
- Diclofenac,
- indomethacin or
- ibuprofen
come into question. In addition to their analgesic effect, these drugs also have an anti-inflammatory effect. As a result, the symptoms disappear in most patients undergoing this therapy.
Not all courses of reactive arthritis respond adequately to cortisone-free anti-rheumatic drugs. Short-term therapy with cortisone may then be necessary. Cortisone is a very strong anti-inflammatory hormone produced naturally in the body.
Cortisone can also be injected directly into the inflamed joint if a bacterial joint infection has been ruled out beforehand.
If there is eye involvement, in particular iritis, an ophthalmologist must be consulted. Immediate treatment is the only way to prevent later visual impairment.
If the causative pathogen of reactive arthritis, e.g. chlamydia, can be identified, short-term antibiotic treatment is prescribed. As chlamydia is transmitted through sexual contact, the partner must also be treated to prevent re-infection.
Antibiotics have no effect on the actual arthritis. However, they serve to eliminate the pathogen at the point of entry and thus reduce the risk of subsequent relapses.
Under certain circumstances, chronic arthritis can develop. This means that the symptoms persist for a longer period of time. Treatment with basic therapeutic agents such as sulphasalazine or methotrexate may then be necessary.
In addition to drug therapy, physical measures such as
- cold therapy (cold air, cryopacks),
- passive movement exercises,
- heat treatment or
- ultrasound
can improve the symptoms.
Reactive arthritis is not a life-threatening condition. Although the onset can be dramatic, they normally heal and do not usually cause permanent joint damage.
The average duration of the disease is 6 months. However, about 20 to 40 percent of patients may develop
- chronic arthritis,
- arthralgias,
- tendon problems or
- relapses
develop. Patients who have also had inflammation of the urinary and genital organs or eye involvement in addition to arthritis are particularly affected.
Sometimes a certain "weather sensitivity" of the joints and spine persists for years after reactive arthritis.
