Reactive Arthritis

Overview
  • Reactive Arthritis, formerly known as Reiter Syndrome, is a member of the seronegative spondyloarthropathies and is characterized clinically by the triad of an acute asymmetric inflammatory arthritis of the lower extremities, urethritis, and ocular inflammation classically occurring several weeks after GI or GU infection. The clinical syndrome of reactive arthritis can be easily remembered with the mnemonic: Can't see, can't pee, can't climb a tree
Etiology and Pathogenesis
  • Although the etiology of Reactive Arthritis is incompletely understood, it appears to be the result of an exuberant immune response to a microbial infection that becomes misdirected toward self-tissues in genetically susceptible individuals. Like all seronegative spondyloarthropathies, Reiter Syndrome is associated with HLA-B27 and the majority of patients carry this allele. A number of infectious agents can trigger the disease but most result in infectious diarrhea (Shigella, Salmonella, Campylobacter jejuni) or urethritis (Chlamydia trachomatis). In keeping with an immune etiology, the symptomology of arthritis typically begins several weeks after the infectious syndrome, likely accounting for the development of a deranged adaptive immune response. Inflammation in Reactive Arthritis centers around the synovium (synovitis) and the ligamentous insertion points in bones known as the enestheses (enthesitis)
Clinical Consequences
  • As mentioned, the classic presentation of Reactive Arthritis is the acute onset of arthritis, urethritis, and ocular inflammation several weeks following a GI or GU infection. The arthritis typically develops rapidly and is asymmetric with a tendency to involve the joints of the lower extremities, especially of the knees, ankles, and feet. The arthritis is often extremely painful to the point that patients avoid walking completely. Urethritis typically accompanies the inflammatory phase and may represent an unmasking of the original smoldering GU infection or be a sterile inflammation of a purely reactive etiology. Ocular inflammation may amount to a simple conjunctivitis or an aggressive anterior uveitis. These tissue-specific symptoms are often accompanied by constitutional symptoms such as fever and fatigue. Symptoms typically subside after several months although the syndrome may flare again in some and in others may evolve into a chronic arthritis.