Chapter 287 THE SPONDYLOARTHROPATHIES
John J. Cush
Peter E. Lipsky
The spondyloarthropathies are a heterogeneous group of disorders that share a number of clinical, radiographic, and genetic features. These disorders include ankylosing spondylitis, Reiter's syndrome, reactive arthritis, psoriatic arthritis, and the enteropathic arthropathies.
The spondyloarthropathies share a constellation of characteristic clinical, radiographic, and immunogenetic manifestations that suggest a common or related etiopathogenesis (Table 287-1) . Distinctive features include a propensity for axial arthritis (sacroiliitis and spondylitis); peripheral arthritis (often asymmetrical and oligoarticular); inflammation at tendinous, ligamentous, or fascial insertions (enthesitis); and a familial pattern of inheritance based on the presence of the class I major histocompatibility complex (MHC) antigen HLA-B27. These disorders can manifest extra-articular features that suggest a particular spondyloarthropathy. Extra-articular manifestations may involve periarticular structures (enthesitis), eyes (conjunctivitis, uveitis), the gastrointestinal tract (oral ulcerations, asymptomatic gut inflammation), the genitourinary tract (urethritis prostatitis, cervitis), the heart (aortitis, heart block), skin (keratoderma blennorrhagicum), or nails (onycholysis, nail pitting). Often, patients will demonstrate overlapping features of more than one condition or will be HLA-B27+ and possess a constellation of symptoms that do not meet the strigent diagnostic criteria of a particular spondyloarthropathy. In such patients the more generic term "spondyloarthropathy" may be more accurate. This distinction allows the clinician to approach these conditions as a group of related disorders and permits the early diagnosis and treatment of affected individuals (Fig. 287-1) .
New diagnostic criteria for the spondyloarthropathies have been proposed (Table 287-2) because previous diagnostic criteria have been shown to exclude many patients with spondyloarthropathy. The broader definitions used these criteria allow for earlier diagnosis and more liberal inclusion of many patients with spondyloarthropathy.
