8Ankylosing spondylitis and reactive arthritis in the developing world
Section snippets
Age of onset and overall prevalence
About 80% of AS patients develop the first symptoms at <30 years of age; <5% of patients present at >45 years.3 The overall prevalence of AS is 0.2–1.1%, and the incidence of AS is 0.5–14 per 100 000 people per year according to studies from different countries.4
Familial forms and heritability
Familial forms of AS are frequent. The risk of developing the disease is 40–60-fold higher in families with AS patients.5 Moreover, two studies now formally estimate heritability as over 90%.6, 7 Age of symptom onset, Bath Ankylosing
Main clinical features of as in the developing world
AS remains the most recognized form of SpA observed in the developing countries. The overall clinical features in adults are rather similar to those reported in white Caucasoids. However, some of them are worth mentioning. A higher rate of involvement of the cervical spine, atlantoaxial subluxation, and ossification of the longitudinal posterior ligament are reported.52 Moreover, one of the commonest and most particular features is the higher frequency of juvenile-onset AS (JoSA).*23, *24, *52
Reactive arthritis in the developing countries
Infections, particularly gastrointestinal infections, are one of the most important medical problems in developing countries. Gastrointestinal infections are linked to water and food contamination as a consequence of a poor urban development. Children are especially susceptible to viral infections and infections by bacteria that might potentially trigger ReA. Such is the case of gastrointestinal infection by species of Salmonella, Shigella, Campylobacter, and less frequently Yersinia, which
Diagnosis
Early diagnosis in SA is a major matter of concern in which the key point is an early identification of sacroiliitis. Sacroiliitis is not always included in diagnosis and classification criteria70, 71 because structural changes in the sacroiliac joints might only become apparent later. A systematic approach to early diagnosis of predominantly axial spondyloarthritis has been developed.72 Such a diagnosis is predictable in every third to fifth patient with chronic (>3 months) low-back pain that
Conclusion
AS and SpA occur in developing countries roughly according to HLA-B27 distribution. But it is certainly not the only factor to consider. The current better understanding of these diseases and their earlier diagnosis would be a major step in their management on a worldwide scale, but would have a particular impact in developing countries. Indeed, in these countries the main problem is poor access to expensive means of diagnosis and/or treatment. Because of the major socioeconomic burden of SpA
References (98)
- et al.
Characterization of B27 haplotypes by oligotyping and genomic sequencing in the Mexican Mestizo population with ankylosing spondylitis: juvenile and adult onset
Human Immunology
(1995) - et al.
HLA-B27 subtypes determination in patients with ankylosing spondylitis from Zulia, Venezuela
Human Immunology
(2003) - et al.
Early-onset ankylosing spondylitis is associated with a functional MICA polymorphism
Human Immunology
(2005) - et al.
Rheumatic diseases in African blacks
Seminars in Arthritis and Rheumatism
(1994) Pathogenesis of ankylosing spondylitis
Best Practice and Research Clinical Rheumatology
(2006)- et al.
Differential association of HLA-B*2705 and B*2709 to ankylosing spondylitis correlates with limited peptide subsets but not with altered cell surface stability
The Journal of Biological Chemistry
(2002) - et al.
HLA-B27 misfolding is associated with aberrant intermolecular disulfide bond formation (dimerization) in the endoplasmic reticulum
The Journal of Biological Chemistry
(2002) - et al.
Spontaneous inflammatory disease in transgenic rats expressing HLA-B27 and human β2m: an animal model of HLA-B27 associated disorder
Cell
(1990) - et al.
ERAAP synergizes with MHC class I molecules to make the final cut in the antigenic peptide precursors in the endoplasmic reticulum
Immunity
(2006) - et al.
Features of spondyloarthritis around the world
Rheumatic Diseases Clinics of North America
(1998)