What is Ankylosing Spondylitis?

Ankylosing spondylitis (AS) is a chronic inflammatory disease of the axial skeleton, with variable involvement of peripheral joints and non-articular structures. AS has a strong genetic predisposition.. The most common symptom of AS is low back pain. It mainly affects joints in the spine and the sacroiliac joint in the pelvis. In severe cases, complete fusion and rigidity of the spine can occur.

Signs and symptoms.

Ankylosing spondylitis is a seronegative spondyloarthropathies, in which rheumatoid factor tests are negative and the characteristic pathological lesion is an inflammation of the site where tensile connective tissue [such as ligaments or tendons] insert into bone. The signs and symptoms of ankylosing spondylitis are nonspecific.

Inflammation of the sacroiliac joint is usually one of the earliest manifestations of AS. The initial symptoms are usually a chronic dull pain in the lower back or gluteal region and stiffness of the lower back in the morning stiffness that improves with activity. Pain is often severe at rest, but improves with physical activity. Loss of spinal mobility, with limitation of anterior flexion, lateral flexion, and extension of the lumbar spine, is seen. The most serious complication of the spinal disease is spinal fracture, AS can occur in any part of the spine or the entire spine. Arthritis in the hips and shoulders may also occur. Other common symptoms of AS include chest pain and generalized fatigue.

Pathophysiology.

Ankylosing spondylitis (AS) is a systemic rheumatic disease, meaning it affects the entire body. There is a strong genetic association. Tumour necrosis factor-alpha (TNF α) and IL-1 are implicated in ankylosing spondylitis. Autoantibodies specific for AS have not been identified.

There is no proof to involve a self- antigen. At least in the related reactive arthritis, which follows infections, the antigens involved are likely to be derived from intracellular microorganisms. There is, however, a possibility that CD4+ T lymphocytes are involved in an aberrant way

Complications

Complications of AS that do not involve the joints are inflammation of the anterior chamber of the eye, Inflammation of the prostate inflammation of the aorta, aortic valve insufficiency progressive fibrosis of the upper portion of the lung. Mortality attributable to AS is largely the result of spinal trauma, aortic insufficiency, respiratory failure, amyloid nephropathy, or complications of therapy such as upper gastrointestinal bleeding.

Diagnosis.

There is no direct test to diagnose AS. The Schober's test is a useful clinical measure of flexion of the lumbar spine performed during the physical examination. Magnetic resonance imaging (MRI), and X-ray studies of the spine, which show characteristic spinal changes and inflammation of the sacroiliac joint, combined with a genetic marker blood test are the major diagnostic tools.

The earliest changes in the sacroiliac joints demonstrable by plain x–ray shows erosions and sclerosis. Progression of the erosions leads to pseudo widening of the joint space and bony ankylosis. X-ray spine can reveal squaring of vertebrae with spine ossification with fibrous band run longitudinally which produce bamboo spine appearance. Options for earlier diagnosis are tomography and MRI of the sacroiliac joints.

Medication

The major types of medications used to treat AS are pain-relievers and drugs aimed at stopping or slowing the progression of the disease. Pain-relieving drugs come in two major classes. The mainstay of therapy include NSAIDs which reduce inflammation and pain. Indomethacin is a drug of choice. Opioid painkillers are used to treat the progression of the disease, They are Disease-modifying anti-rheumatic drugs, Tumour necrosis factor-alpha blockers and Anti-interleukin-6 inhibitors.