Spinal ankylosing spondylitis: a variant form of ankylosing spondylitis or a distinct disease entity?

Female with Ankylosing Spondylitis from the 7th–6th century BCE Lori Berd burial (Armenia)

A female skeleton from the Lori Berd archaeological cemetery, located near the city of Stepanavan (Lori Province of Armenia) is described. Palaeopathological analysis revealed a variety pathology (ankylosis of the sacroiliac joints, ankylosis of the vertebrae, syndesmophytes, ankylosed of the costovertebral and costotransverse joint fusions, kyphosis, lordosis, fracture of the anterior inferior iliac spine and traumatic lesions). This paper reports a new case of ankylosing spondylitis in a skeleton and a differential diagnosis performed to determine the etiology of the condition. The vertebral bodies remodel and together with the associated syndesmophytes form a continuous, smooth bone surface that is sometimes referred to as “bamboo spine”. In this skeleton changes in the spine, ribs, the sacrum, acetabulum, head of the femur and greater trochanter, as well as the anterior inferior iliac spine are typical of ankylosing spondylitis in advanced stage. Addtionally, there were signs of a traumatic death with injuries sustained to the scapula and vertebra. Using osteological markers in combination with the reconstruction of the archaeological context, the burial pattern suggests that the pathology the female suffered was likely due to her physical deficiencies.

Imaging for the diagnosis and follow-up of ankylosing spondylitis: development of recommendations for clinical practice based on published evidence and expert opinion

OBJECTIVE

To develop recommendations regarding imaging studies for the diagnosis and follow-up of patients with axial forms of ankylosing spondylitis (AS) seen in everyday practice.

METHODS

Evidence from the literature and expert opinion were used to develop the recommendations. Using the Delphi consensus procedure, a scientific committee selected five areas of interest, about which scientific evidence was sought by searching Medline and the databases maintained by the French Society for Rheumatology, European League against Rheumatism, and American College of Rheumatology. Based on this evidence, a panel of experienced rheumatologists drafted recommendations, using expert opinion if needed to supplement gaps in evidence. For each recommendation, the level of evidence and the extent of agreement among the experts were specified.

RESULTS

The five areas of interest dealt with the usefulness of imaging studies for the diagnosis, follow-up, prognostic evaluation, and assessment of treatment responses in patients with AS. The literature search retrieved 144 articles based on titles and abstracts. After elimination of articles that did not include an analysis of the radiological evaluation of AS, 73 articles were left for review. Eight recommendations were drafted then validated by having all panel participants vote during a final meeting.

CONCLUSION

Eight recommendations about the use of imaging studies in patients with AS were developed. They can be expected to improve clinical practice uniformity and, in the longer term, to optimize the management of patients with AS.

Assessments in ankylosing spondylitis

Assessment of disease status and response to therapy in ankylosing spondylitis is a rapidly expanding area of research. The assessment in ankylosing spondylitis international working group has contributed greatly to this development, defining core sets of health domains for use in daily practice and in clinical trials, developing and validating measurement instruments corresponding to these health domains, and developing response and remission criteria for use in clinical trials. This chapter reviews available measures of three major areas of disease impact in ankylosing spondylitis (disease activity, structural damage and functioning), and discusses which measures are relevant for use in clinical practice.

Radiologic diagnosis and pathology of the spondyloarthropathies

Five different subtypes of spondyloarthropathy (SpA) are now recognized. Clinical and radiologic involvement of the sacroiliac joint is an outstanding feature of the SpA, especially ankylosing spondylitis (AS). In this partly debilitating form of SpA a unique type of inflammatory axial involvement is observed which is characterized by inflammation and new bone formation at different spinal sites. In longstanding disease sacroiliitis, spondylitis and spondylodiscitis are easily recognized by conventional radiography and even better by computed tomography--especially when bony changes have already taken place. The advantage of dynamic magnetic resonance imaging (MRI) is to visualize morphologic changes and inflammation at the same time. This facilitates detection of sacroiliitis and spondylitis/spondylodiscitis at early time points. Hopefully, this will lead to other forms of therapy to prevent ankylosis of the spine. The origin of the granulation tissue infiltrating cartilage and bone in AS might be the synovium, the subchondrium or the bone marrow itself. T cells and macrophages seem to play an important role in this inflammatory process in which TNF-alpha is present in severe cases. The mechanisms responsible for the increased bone formation observed in the course of AS are unknown.

Prevalence of spondylarthropathies in HLA-B27 positive and negative blood donors

OBJECTIVE

To determine the overall prevalence of spondylarthropathy (SpA) among whites.

METHODS

To screen for SpA symptoms, such as inflammatory back pain (IBP), joint swelling, psoriasis, and uveitis, or a specific family history, questionnaires were mailed to 348 blood donors (174 HLA-B27 positive and 174 HLA-B27 negative). From the responding 273 persons (78%; 140 B27 positive, 133 B27 negative), 126 were selected for further evaluation based on the symptoms reported. Of this group, 90 persons agreed to undergo physical examination (71.4%; 46 B27 positive, 44 B27 negative). There was no difference between the B27-positive and -negative groups in terms of age (mean +/- SD 38.4 +/- 10 versus 39.5 +/- 11 years) and sex ratio (67% versus 68% were men). In addition, 58 donors (32 B27 positive, 26 B27 negative) agreed to undergo magnetic resonance imaging (MRI) of the sacroiliac joints. A diagnosis of SpA and ankylosing spondylitis (AS) was made according to the European Spondylarthropathy Study Group criteria and the New York criteria.

RESULTS

SpA was diagnosed in 20 persons: 19 of 140 B27-positive (13.6%) and 1 of 133 B27-negative (0.7%) subjects (15 male and 5 female). AS was diagnosed in 9 persons (7 male and 2 female; 45%), undifferentiated SpA (USpA) in 7 (5 male and 2 female; 35%), psoriatic arthritis (PsA) in 3 (2 male and 1 female; 15%), and chronic reactive arthritis (ReA; Reiter's syndrome) in 1 (male; 5%). On the basis of a B27 frequency of 9.3% among the population of Berlin (3.47 million persons), the estimated prevalence of SpA was 1.9%, AS was 0.86%, USpA was 0.67%, and PsA was 0.29%. The relative risk of developing SpA in B27-positive subjects was calculated as 20.7 (95% confidence interval 4.6-94.2; P = 0.001). Of 58 persons with IBP, sacroiliitis was detected by MRI in 15 of 32 B27-positive (46.9%) and 1 of 26 B27-negative (3.9%) subjects (P = 0.002). Four of these 16 donors did not fulfill diagnostic criteria for SpA.

CONCLUSION

With a calculated prevalence of 1.9%, spondylarthropathies are among the most frequent rheumatic diseases in the white population. HLA-B27 positive persons carry a 20-fold increased risk of developing SpA. AS and USpA are the most frequent SpA subtypes. Persons with IBP who are B27 positive have a 50% likelihood of having sacroiliitis.

The epidemiology of ankylosing spondylitis

This review focuses on various epidemiological aspects of ankylosing spondylitis (AS). Diagnostic criteria currently available are described, and their use in scientific studies as opposed to everyday clinical practice is discussed. Present knowledge of the prevalence of AS is addressed in detail with particular emphasis on discrepancies caused by variations in population frequencies of HLA B27 and those caused by differences in study designs.