Reactive arthritis (synonym: postinfectious arthritis; ICD-10 M02.3-: reactive arthritides) is a secondary disease after gastrointestinal (affecting the gastrointestinal tract), urogenital (affecting the urinary and reproductive organs), or pulmonary (affecting the lungs) infections. It refers to joint involvement in which pathogens are (usually) not found in the joint (sterile synovitis). It typically affects unilaterally (unilaterally) single large joints of the lower extremity. However, bacterial antigens may be detectable. Reiter’s disease (synonyms: Reiter’s syndrome; Reiter’s disease; arthritis dysenterica; polyarthritis enterica; postenteritic arthritis; posturethritic arthritis; undifferentiated oligoarthritis; urethro-oculo-synovial syndrome; Fiessinger-Leroy syndrome; Engl. Sexually acquired reactive arthritis (SARA); named after the German physician Hans Reiter, 1881-1969; ICD-10: M02.3- Reiter’s disease) is a special form of “reactive arthritis“. It is a secondary disease after gastrointestinal or urogenital infections and is characterized by the symptoms of the Reiter triad (see “Symptoms – Complaints” below). The disease belongs to the group of predominant peripheral spondyloarthritides (SpA, pSpA). Furthermore, it belongs to the group of seronegative spondyloarthritides (synonym: seronegative spondyloarthropathy), in which inflammation of the small vertebral joints (spondylarthritis) is present. These diseases are distinguished from rheumatoid arthritis (chronic polyarthritis) by the absence of rheumatoid factors (= seronegative). Furthermore, the disease belongs to the predominant peripheral spondyloarthritides (SpA, pSpA). The development of the disease is assumed to be due to an immunological process. One can distinguish the following forms of reactive arthritis according to the cause:
- Postenteritic – occurring after a gastrointestinal infection; up to 30% of those affected by an infection with Campylobacter, Salmonella, Shigella or Yersinia develop reactive arthritis (joint inflammation).
- Posturethritic – occurring after a urogenital infection such as gonorrhea, non-gonorrheal urethritis (NGU), mycoplasma, or after a urinary tract infection; up to three percent of those affected by chlamydial urethritis develop reactive arthritis
- Reactive arthritis can also develop after respiratory tract (respiratory tract) infections
According to the association with HLA-B27, a distinction can be made in:
- HLA-B27-associated – belongs to the group of spondyloarthritides – often oligoarticular involvement (usually one or a maximum of 2 to 4 joints are affected), often focused on the lower half of the body, extraarticular (“outside joints”) symptoms.
- Non-HLA-B27-associated – often polyarticular involvement (more than five joints), no extraarticular symptoms.
The prevalence (disease incidence) is 40 per 100,000 adults for reactive arthritis following chlamydial infection. The incidence (frequency of new cases) of reactive arthritis after chlamydial infection is about 4-5 diseases per 100,000 inhabitants per year.Course and prognosis: Between the occurrence of reactive arthritis and a clinically manifest enteritis (gastrointestinal infection) or. As a rule, symptomatic treatment of acute arthritis with non-steroidal anti-inflammatory drugs (NSAIDs) and physical therapy (e.g. cryotherapy/cold therapy) are usually sufficient. Only if an infection is still detectable, antibiotic therapy is indicated (indicated). In severe courses, glucocorticoids can be used. In case of a chronic course, a basic therapy with e.g. sulfasalazine (possibly even with methotrexate (MTX)) must be given.Up to 80% of cases of reactive arthritis heal after 12 months. If the disease is HLA-B27 associated, severe courses occur and the disease tends to become chronic.
