Pathogenesis (disease development)
Reactive arthritis is a secondary disease after gastrointestinal (stomach and intestinal tract), urogenital (urinary and genital), or pulmonary (lung) infections. It refers to joint involvement in which pathogens are (usually) not found in the joint (sterile synovitis/articular synovitis). It typically affects unilaterally (unilaterally) single large joints of the lower extremity. However, bacterial antigens may be detectable.
Reiter’s disease is a specific form of “reactive arthritis“. It is a secondary disease following gastrointestinal or urogenital infections and is characterized by the symptomatology of Reiter’s triad (see “Symptoms – Complaints” below).
The pathogenesis is based on an immunological process. Immune complexes enter the joint and trigger a chronic (sterile) synovitis (inflammation of the synovial membrane). This explains why no triggering pathogens are detectable in the synovial fluid.
Etiology (causes)
Biographic causes
- Genetic burden from parents, grandparents (up to 80% of affected individuals are HLA-B27 positive).
Disease-related causes
Infectious and parasitic diseases (A00-B99).
- Infection, especially with Campylobacter, Salmonella, Shigella, or Yersinia (bacterial enteritis)).
- Gonorrhea
Genitourinary system (kidneys, urinary tract – sex organs) (N00-N99)
- Chlamydial urethritis – inflammation of the urethra caused by bacteria of the species Chlamydia.
- Urethritis (urethritis)/non-gonorrheal urethritis (NGU) caused by mycoplasmas, especially Ureaplasma urealyticum.
