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Ankylosing spondylitis (as)

What is Ankylosing spondylitis (AS)?

Ankylosing spondylitis (AS) (ANK-ki-low-sing spon-di-LIE-tis) is a chronic inflammatory disease that primarily affects the sacroiliac joints (where the spine attaches to the pelvis), spine, and hip joints. Ankylosing is a term meaning stiff or rigid and spondylitis means inflammation of the spine. 

Enthesitis (inflammation of the place where ligaments and muscles attach to bones) accounts for much of the pain and stiffness of AS. This inflammation eventually can lead to bony fusion of the joints (where the fibrous ligaments transform to bone, and the joint permanently grows together). 

Other joints can also develop synovitis (inflammation of the lining of the joint), with lower limb joints more commonly involved than upper-limb joints. 

AS is one of a family of arthritis-related diseases called the seronegative spondylarthropathies. Seronegative means people with the disease test negative for the antibody rheumatoid factor and spondylarthropathy means joint disease of the spine. Ankylosing spondylitis most often develops in young adult men and it lasts a lifetime. 

Early diagnosis and proper treatment can help control the pain and stiffness associated with AS, and may reduce or prevent deformity. Daily exercise of the affected joints is the most important treatment for AS. Medications that relieve pain and inflammation (usually nonsteroidal anti-inflammatory drugs) will allow you to get the exercise you need to maintain flexibility and mobility.  Newer biologic agents such as tumor necrosis factor inhibitors can be very effective in patients who do not have significant relief with nonsteroidal anti-inflammatory drugs.  Although these agents are very effective in the short term, it remains to be seen whether they can alter the progressive ankylosis (fusion of some or all spinal joints) of the disease in the long term.

What causes it?

Although the cause of ankylosing spondylitis (AS) is not known, there is a strong link to the genetic marker HLA-B27. Studies show that 90 percent of people with AS are positive for the HLA-B27 marker. However, fewer than five percent of HLA-B27-positive individuals ever develop AS or a related disease. If an HLA-B27-positive person has a family member with AS, that person’s risk of developing spondylitis is significantly higher than that of other HLA-B27-positive people. This increased risk suggests that other genes, in addition to HLA-B27, are involved in the spondyloarthropathies. Some researchers have proposed that some type of infection may trigger AS in those who are genetically susceptible, but this theory has been difficult to confirm.

What are the symptoms/effects?

Pain in the low back and buttocks are usually the first symptoms of ankylosing spondylitis (AS). In contrast to mechanical low back pain, low back pain and stiffness in AS patients are worse after a period of rest or on waking up in the morning and improve after exercise, a hot bath or a shower. Progressive stiffening of the spine is usual, with ankylosis (fusion of some or all spinal joints) occurring after some years of disease in many, but not all, patients. A majority of patients have mild or moderate disease with intermittent exacerbations and remissions and maintain some mobility and independence throughout life.

Other symptoms you may have include:

  • Sacroiliitis (inflammation of the sacroiliac joint, which is the joint where the spine attaches to the pelvis) is the most common initial feature of AS. It causes pain in the buttocks that sometimes radiates down the thighs, but never below the knee.
  • Inflammatory sacroiliac and back pain usually begins slowly (over several weeks or months), persists for more than three months, is worsened by inactivity (such as nighttime rest), and is improved by exercise.
  • Inflammation and stiffness travel up the spine over a period of years to produce progressive pain and restriction.
    • As your lumbar spine stiffens and fuses, you may become unable to touch fingers to floor by a considerable distance.
    • Disease in the thoracic spine may result in a stooped-shoulder appearance.
    • Rigidity of the chest wall reduces your ability to take a deep breath.
    • Involvement of the thoracic spine may be associated with chest pain and tenderness of the sternum (breastbone), which you may confuse with heart-related chest pain. If in doubt, always check with your doctor.
    • Disease in the cervical spine will restrict your ability to extend and rotate the neck.
    • Enthesitis (inflammation of the place where ligaments and muscles attach to bones) accounts for much of the pain, stiffness, and restriction at the joints. Enthesitis affects the joints of the spine, but also commonly affects the plantar fascia (a fibrous band that runs along the bottom of the foot) and Achilles tendon insertion points at the heel, producing disabling pain.
    • Fatigue is common and troublesome in people with AS, and impaired sleep due to pain and stiffness is a major contributor to this fatigue.
    • Fever and weight loss may occur.
    • Synovitis (inflammation of the lining of the joint) may precede, accompany, or follow the onset of spinal symptoms. Hips, knees, ankles, and toe joints may be affected, but upper-limb joints are less commonly involved.
    • Acute anterior uveitis (iritis) develops at some time in about one-third of people with AS. If you develop red, sore, gritty eyes or blurring of vision, you must get urgent treatment by an ophthalmologist. Untreated iritis can lead to permanent visual impairment.
    • Up to one-quarter of people with AS also have features of inflammatory bowel disease. If you develop diarrhea and abdominal discomfort, with or without passage of blood or mucus, you should consult your doctor.
    • Systemic inflammation can also result in aortic insufficiency, pulmonary fibrosis, prostatitis (inflammation of the prostate) or salpingitis (inflammation of the uterine tube) in  less than 5 percent of people with AS.
    • Osteoporosis develops in many patients and, without adequate treatment, leads to vertebral and other fractures.
    • Depression, with loss of libido and reduced capacity for work, may contribute to lack of wellbeing.
    • Pregnancy may pose particular problems for young women with AS. Unlike rheumatoid arthritis, there is no tendency for AS to remit during pregnancy. Sacroiliitis may produce severe pain during delivery and fused sacroiliac joints may hinder the process.

How is it diagnosed?

A diagnosis of ankylosing spondylitis (AS) is usually made by a rheumatologist which requires the following:

  • X-ray evidence of sacroiliitis (inflammation of the sacroiliac joint, which is the joint where the spine attaches to the pelvis)

And one of the following three clinical criteria:

  • Low back pain and stiffness for more than 3 months, which improves with exercise, but is not relieved by rest
  • Limitation of motion of the lumbar spine in both the bending to the side and to the front.
  • Limitation of chest expansion relative to normal values corrected for age and sex

Early in the disease course, however, the X-ray evidence required by the criteria may not be present. Your doctor can make a diagnosis of AS based on your symptoms and start treatment without the X-ray evidence.

If your symptoms lead your doctor to believe that you have AS, he or she may run a blood test for the presence of the HLA-B27 genetic marker , the presence of which will enhance the diagnosis. Your doctor may also run some tests to rule out other causes of back and sacroiliac pain, including:

  • Prolapsed intervertebral disc
  • Fibromyalgia
  • Spinal tumors
  • Bone tumors
  • Infection in spinal or sacroiliac joint
  • Pelvic inflammatory disease
  • Metabolic bone disease
  • Diffuse idiopathic skeletal hyperostosis (DISH, sometimes called Forrestier’s disease)

What are the treatment options?

Although no medication or therapy can prevent ankylosing spondylitis (AS) from progressing, a treatment plan of medication and exercise can help you maintain a normal upright posture and spinal mobility, minimize the impact of hip and other joint manifestations, and reduce pain and stiffness. A full treatment plan will include the following:

  • Exercise: Stretching and spinal exercise can improve mobility and posture and minimize the long-term impact of AS. Daily spinal exercise can take the form of stretching prescribed by a physical therapist, gym exercises, or participation in a favored sport (swimming is a good choice, but contact sports should be considered with caution). Before exercising, a warm shower followed by light arm movements or walking will make the exercise more comfortable.
  • Posture: Maintaining or improving spinal alignment is one of the primary goals of treatment. Maintaining correct posture is essential. It is important for you to learn to monitor changes in your spinal alignment so postural adjustments can be made and progressive worsening can be prevented. You can check your posture and monitor changes a few different ways.
  • Stand against a wall with heels, buttocks, and shoulders touching the wall.
  • With your chin parallel to the floor, try to touch the back of your head to the wall.
  • Measure your body height frequently Breathing: Deep breathing exercises and rib cage expansion, along with avoidance of cigarettes, can help keep your chest and rib cage flexible.(This same sentence is repeated down, which one should we keep?)

You should avoid stooped positions in your daily life. Do not slouch in your chair and do not lean over a work surface for a long time. Working at a slightly tilted drafting table can help keep you upright. Take frequent work breaks to stretch.

When sleeping, you should try to find a pillow that will support your head while still allowing your neck to be fully extended. There are specially contoured pillows available in the stores for this purpose. Changing positions frequently in the night is also helpful in reducing morning stiffness.

Lying on your stomach for 15 minutes per day can help maintain hip extension. If you cannot lie flat on your stomach, a pillow or folded towel under the abdomen may help. If you cannot turn your head to the side, place a rolled-up towel under your forehead. If these tips still don’t help you get in the position, lie on your bed on your back with buttocks at the edge and hips extended.

  • Work and recreation adjustments: You may need to make changes to your work situation, such as using a drafting table rather than a standard desk to avoid stooping over, changing from a job that requires much bending and lifting, or taking breaks from a sedentary job to move around or lie on the ground to extend your spine. You may need to change your recreational outlets, such as you may need to avoid contact sports to take up swimming, badminton, walking, or cross-country skiing.
  • Medications:
    • Nonsteroidal anti-inflammatory drugs (NSAIDs, such as ibuprofen, indomethacin, naproxen, etc.) are used to control the pain and stiffness of AS enough to allow an active, sustained program of exercise. Long-acting NSAIDs, (such as Indomethacin SR) taken at night may be valuable in promoting sound sleep and reducing morning stiffness.
    • Corticosteroid injections (such as cortisone) may relieve enthesitis (inflammation of the tendon and muscle insertion to bone sites) at the Achilles tendon or plantar fascia insertion sites at the heel.
    • Oral corticosteroids(such as prednisone and prednisolone, etc.) can help calm severe symptomatic flares or they can be used to maximize progress at the beginning of an exercise program. They probably won’t, however, be used long term.
    • Tumor necrosis factor inhibitors (such as etanercept and infliximab) are now being used to treat pain and to improve function and mobility. It is not yet known if these drugs can modify the course of the disease and prolong the time before joints begin to fuse.
    • Other medications that your doctor may try, but are not the main therapeutic options, include sulfasalazine and methotrexate.
  • Surgery: Total hip, shoulder or knee replacement are options for restoring mobility in those joints when they have become severely damaged. Corrective spinal surgery has become a safer prospect since the advent of magnetic resonance imaging and may be necessary if your spine fuses into a severely bent position.
  • Support and counseling: Problems of fatigue, poor sleep, depression, low self esteem, work difficulties, etc. may lead you to seek support, counseling, or antidepressant medications.
  • Steroid eye drops: Steroid eye drops may be used to treat acute anterior uveitis, a complications associated with AS. These drops should not be used without an eye exam by an ophthalmologist to make sure there is not some other problem, such as a serious viral infection, that steroid eye drops would make worse. Sometimes drops that relax the iris muscle, which controls the pupil, is used to relieve pain.

Who is at risk? /How can I prevent it?

The prevalence rate of ankylosing spondylitis (AS) can vary from 0.2 percent in white Americans to 1.4 percent in Norwegians, to 6 percent in Haida Native Americans in northern Canada. The prevalence generally, but not exclusively, reflects the prevalence of the genetic marker HLA-B27 in the different populations. Men are disproportionately affected, with three men affected for every woman affected. Some investigators say that more women are affected than are diagnosed because the disease affects women somewhat differently than men and is not recognized as well.

Age of onset typically ranges from adolescence to 35 years, peaking around 28 years. AS does occur in children, but it does not usually involve the spine until later in the course, so it often takes years to come to a firm diagnosis.