Ankylosing spondylitis

Ankylosing spondylitis (AS) is a chronic, progressive inflammatory arthritis primarily affecting spine and sacroiliac joints, causing eventual fusion of the spine; it is a member of the group of the spondylarthropathies. Complete fusion results in a complete rigidity of the spine, a condition known as bamboo spine. more...

Treatment is with physiotherapy and medication. Some cases remain mild, while other result in marked disability.

Signs and symptoms

The typical patient is a young man of 15-30 years old (although women are also affected) with pain and stiffness in the spine. It is also associated with iridocyclitis (anterior uveitis), ulcerative colitis, psoriasis and Reiter's disease, through HLA-B27 (see below).

Osteopenia or osteoporosis of AP spine, causing eventual compression fractures and a back "hump" if untreated.

Organs affected by AS, other than the axial spine, are the hips, heart, lungs, heels, and other areas (peripheral).

Ankylosing spondylitis affects the eyes in up to 40 percent of cases, leading to episodes of eye inflammation called acute iritis. Acute iritis causes eye pain and increased sensitivity to light (photophobia).

Diagnosis

The diagnosis is by X-ray studies of the spine, which show characteristic spinal changes and sacroiliitis. A normal X-ray does not exclude the disease.

Variations of the HLA-B gene increase the risk of developing ankylosing spondylitis, those with the HLA-B27 variant are at highest risk of developing the disorder. HLA-B27, demonstrated in a blood test, is occasionally used as a diagnostic, but does not distinguish AS from other diseases and is therefore not of real diagnostic value. Effective Diagnosis can also happen via MRI scans. Unattended cases normally lead to knee pain, resulting in a fair assumption of normal rheumatism.

Pathophysiology

AS is a systemic rheumatic disease, and about 90% of the patients are HLA-B27 positive. HLA-DR and IL1ra are also implicated in ankylosing spondylitis. Although specific autoantibodies cannot be detected, its response to immunosuppresive medication has prompted its classification as an autoimmune disease.

Hypotheses on its pathogenesis include a cross-reaction with antigens of the Klebsiella bacterial strain (Tiwana et al. 2001). Particular authorities argue that elimination of the prime nutrients of Klebsiella (starches) would decrease antigenemia and improve the musculoskeletal symptoms. On the other hand, Khan (2002) argues that the evidence for a correlation between Klebsiella and AS is circumstantial so far, and that the efficacy of low-starch diets has not yet been scientifically evaluated. Similarly, Toivanen (1999) found no support for the role of kebsiella in the etiology of primary AS.

Epidemiology

The sex ratio is 3:1 for men:women. In the USA, the prevalence is 0.25%, but as it is a chronic condition, the number of new cases (incidence) is fairly low.

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