Etiology And Pathogenesis Of Ankylosing Spondylitis
Ankylosing spondylitis (Bechterew's disease) is a rheumatic inflammatory disease, manifested a primary lesion of intervertebral joints and sacroiliac joints. In addition, Ankylosing spondylitis, especially in the initial stage of the disease, often arthritis of peripheral joints. The prevalence of Ankylosing spondylitis about almost the same as in rheumatoid arthritis. However, there are exceptions: the disease is not common in Australian Aborigines and stoves seen in blacks in Africa and America. Approximately 90% of patients with clinically distinct forms of Ankylosing spondylitis - men, with onset usually fall on the age of 17-25 years. But Ankylosing spondylitis may develop as women, children and the elderly. Suggest that women suffer from them not less than men, but they Ankylosing spondylitis occurs mainly in the erased or atypical form.
Etiology and pathogenesis of ankylosing spondylitis is not definitively established. The possible connection between Ankylosing spondylitis with urogenital and intestinal infections. Do not rule out that the leading role in the pathogenesis of inflammatory processes play an immunopathological mechanism. Some authors, based on indirect data, tend to think Ankylosing spondylitis special variant of reactive arthritis, etiologically associated with enteric pathogens such as pneumonia. However, convincing evidence that the direct participation of an infectious agent in the development of Ankylosing spondylitis, are absent, and the use of antibiotics, as a rule, no significant effect on the course of the disease.
Important role in the development of ankylosing spondylitis given to hereditary predisposition. Genetic marker of the disease is considered to be major histocompatibility complex antigen HLA-B27, which is found in 85-95% of patients, whereas in the general population frequency of the carrier-ment of the antigen is 10-14%. The presence of antigen HLA-B27 correlated with the development of sacroiliac and anterior uveitis Hereditary disease Ankylosing spondylitis confirm an increased frequency of lesions of a few members of one family (family aggregation) and a high degree of concordance for the disease in identical twins.
The defeat of the spine is usually ascending in nature: first, in the pathological process involved the sacroiliac joint, and intervertebral joints of the lumbar spine, then the joints of the thoracic and in the later stages - cervical. In the same sequence involve other structures of the spine, in particular, spinal ligaments, intervertebral discs and vertebral bodies. When morphological study of the synovial membrane obtained from the affected joints revealed signs of chronic inflammation, characterized mainly plasma infiltration with moderate proliferation of integumentary cells and small deposits of fibrin on the surface of synovitis. The inflammatory process is characterized by slow but steadily progressive course. With time going destruction of articular cartilage, there are erosive changes in subchondral bone and fibrous, and then the bone ankylosis of sacroiliac and intervertebral joints. Furthermore, there is sclerosis, dysplasia and ossification of cartilage (ossification) of the synovial membrane and articular capsule, which leads to complete immobility of affected joints. At later stages of the disease, predominantly in women, similar changes develop in lonnom junction.
In parallel, there are sclerotic changes and ossification of spinal ligaments, especially in the field of attachment to the bodies of the vertebrae. The defeat of the intervertebral discs causes them to degenerative changes and the gradual destruction of the fibrous ring with subsequent ossification. Ossification of the fibrous ring at the periphery of the intervertebral disc and the development of bony growths on the edges of vertebral bodies leads to the formation of bone bridges between them - syndesmotic Education syndesmotic and ossification of spinal ligaments exacerbate the limited mobility of the spine caused by ankylosis of intervertebral joints. There is also a defeat of vertebral bodies, manifesting the appearance of bone de. defects (erosions) of the front edge and adjacent to the reflex-forming disk plates. As a result, the deformation of the vertebrae may occur.
As already mentioned, in ankylosing spondylitis, along with the spine and joints are often involved the limbs. In addition you may experience inflammatory-degenerative processes, in particular, eye, aorta, shells, hearts, lungs. Perhaps the development of amyloidosis of the kidneys and other internal organs.
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