Arthritis and Rheumatology Conditions and Diagnoses

What is spondyloarthritis?

Spondyloarthritis (SpA) is a type of arthritis that involves joints along the spine as well as hips, shoulders, knees and ankles.

When there is arthritis in a joint it can be warm and swollen, and painful to move or sometimes just to touch. This is a result of inflammation. In SpA, the inflammation often occurs where tendons attach our muscles to bones, or where ligaments attach to bones together.

SpA can occur in children and adults. There are many forms of SpA, with the most common one known as ankylosing spondylitis (AS). When this occurs in children it is called juvenile ankylosing spondylitis (JAS). The name comes from the Greek words for 'bent' (angkylos) and 'spine' (spondylos), and describes what can occur if the disease is present for many years without treatment. Sometimes patients have several, but not all of the features of JAS, and we say they have an incomplete or undifferentiated form of the disease.

SpA usually develops in people who are 20-30 years old, but one out of every 6 or 7 cases begins in the teenage years. If you haven't developed AS by the time you're 45, chances are good that you won't. Although the exact number of individuals SpA is not known, it occurs in about 5-9 out of every 1,000 people. Since about half of these people has AS, there are close to 500,000 cases in the US alone.

Causes of SpA

SpA affects people all around the world, and although its exact cause is not known, it occurs mostly because of our genetic makeup.

What are the signs and symptoms of SpA?

There are several conditions that fall under the SpA category, including:

• Juvenile ankylosing spondylitis (JAS)
• Undifferentiated SpA
• Reactive arthritis
• Arthritis associated with inflammatory bowel disease (IBD) and psoriasis (See table 1)

Since they differ in important ways, each will be considered separately.

Juvenile Ankylosing Spondylitis (JAS)

In many patients, JAS begins as arthritis in the large joints of the lower extremities, particularly the hips and knees. It is also common to have pain and tenderness where tendons or ligaments attach to bones--most commonly at the heel, the top and bottom of the kneecap (patella), the 'ball' of the foot, and bottom of the foot at the heel (plantar fascia). Arthritis in the joints of the foot, particularly between the tarsal and metatarsal bones in the mid-foot region (tarsitis), is also relatively common. It is uncommon for arthritis to occur in the elbows and wrists, but it does occur in the shoulders. All children with JAS develop arthritis in the lower back (sacroiliitis) and spine.

Sometimes patients with JAS will have inflammation in other parts of their body. Eye inflammation (anterior uveitis) occurs in approximately one half of patients. Uveitis almost always causes pain and redness, and therefore is very different from the eye inflammation that can occur with juvenile rheumatoid arthritis (JRA), which often does not cause symptoms. Less commonly, heart valves can be affected in patients with JAS or AS.

Diagnosing JAS can be difficult if the spine and/or lower back are not involved when other symptoms begin, since it may not occur for several years after other symptoms have begun. In studies looking at children who eventually developed JAS but initially had arthritis that looked just like JRA, it was found that they were more likely to have had lower extremity arthritis and pain and tenderness where tendons or ligaments attach to bones during the first year of their illness, and frequent involvement of the foot (tarsitis).

Thus when many of the symptoms are present but the child has yet to develop back pain (sacroiliitis), we typically call it "probable" JAS, or classify it as an "undifferentiated" SpA. Some studies suggest that as many as 50% of these children will develop complete JAS with time either in late adolescence or as an adult. However, this depends on genetic factors, and it is not yet possible to predict with certainty who will and who won't progress.

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Undifferentiated SpA

Undifferentiated SpA includes SEA syndrome (Seronegative Enthesopathy and Arthropathy). These patients have inflammation where a tendon or joint inserts on bone (enthesitis) along with arthritis, and like most individuals with JRA, do not have a rheumatoid factor (a protein which is made by the white blood cells). It is not clear which patients with SEA syndrome will go on to develop Ankylosing Spondylitis (AS). Studies that have been done suggest this is quite variable, and could be anywhere from 10-90% within about 5 years. The wide variation in outcome may be due to environmental and genetic factors.

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Reactive arthritis (ReA)

Reactive arthritis (ReA) usually occurs 2-4 weeks after an infection in some other part of the body like the gastrointestinal tract. Gastrointestinal infections are usually accompanied by diarrhea, abdominal pain, and cramping, and are caused by bacteria like Salmonella. The inflamed joints do not contain these bacteria, but are still the site where many inflammatory cells accumulate and cause symptoms for reasons that are unknown. Like other forms of SpA, development of ReA is much more common in people with HLA-B27 (This is a gene that is present in about 70-90% of patients with arthritis that affects the spine). ReA in children can be short-lived with complete resolution of symptoms, or may continue with a more chronic course. Some patients may go on to develop complete AS over several years, but again this is difficult to predict.

Arthritis Associated with Inflammatory Bowel Disease (IBD) or Psoriasis

Arthritis occurs more commonly in people with IBD such as Crohn's disease or ulcerative colitis, than in the general population. The arthritis can involve peripheral and/or spinal joints including the sacroiliac (SI). When the spine or SI joints are involved it is usually associated with the HLA-B27 gene. Peripheral or spinal arthritis is also more common in people with psoriasis, with the latter being associated with HLA-B27.

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How is spondyloarthritis diagnosed?

There are a number of signs and symptoms doctors use to diagnose SpA. This information may come from a history of how your symptoms affect you, your physical exam findings, and abnormal X-rays of your sacroiliac joints (See table 2 for definitions). Making this diagnosis can be difficult as some findings are not present when the disease starts, but develop over time, while others may never appear. This is particularly true in children, where lower back pain, sacroiliitis and abnormal X-ray findings are less common in the early stages. As a result juvenile SpA is frequently mistaken for JRA.

Your doctor may do a test for HLA-B27 if he or she thinks you have SpA. But remember, even though most people with SpA have HLA-B27, most people with HLA-B27 do not have SpA. Again, this is to test for the HLA-B27 gene that is present in about 70-90% of patients with arthritis that affects the spine. That means that even if you have HLA-B27, you may not have SpA or AS. Other symptoms and signs of the disease must be present for the diagnosis to be made. When used along with other information the HLA-B27 test can be quite helpful, particularly in recognizing juvenile SpA and differentiating it from JRA.

Distinguishing Juvenile Spondyloarthritis from JRA

Some studies have suggested that as many as 10-15% of children diagnosed with JRA may eventually develop a SpA. When the arthritis first begins there are several clues that are useful in deciding whether it is SpA or JRA (See table 3). In general, SpA tends to occur in older boys and involve a small number of large joints (i.e. hips, knees and ankles). Back pain or stiffness is more frequent in pediatric SpAs than JRA, and anti-nuclear antibodies (ANA) are rare in SpA, while HLA-B27 is common.

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What are the usual treatments?

Juvenile SpA is treated like JRA in many ways, although treatments are tailored to the severity of your disease and where it is most prominent. Doctors most often use non-steroidal anti-inflammatory drugs (NSAIDs) initially.
Arthritis in the knees, ankles and hips can frequently be treated with an injection of corticosteroids into the joint space to help lessen inflammation. Unfortunately, arthritis of the spine including the sacroiliac joint cannot be treated this way.

Both sulfasalazine and methotrexate have been helpful for patients with SpA and peripheral arthritis. These are called disease modifying anti-rheumatic drugs (DMARDs) and they require that your doctor obtain blood tests to look for lowering of your blood counts or problems with your liver.

Medications called biologics have been shown to be highly effective in reducing symptoms in adults with SpA. These drugs also work well in children with JRA, and are expected to work for SpA, although fewer studies have been done. Your doctor should discuss this with you.

Another very important component of treatment is physical therapy and activity aimed at maintaining flexibility and improving strength. Activities like swimming are particularly good, as they do not put weight on your joints. Different types of shoe inserts or even special shoes can be used to relieve pain when there is arthritis in your foot (tarsitis) or if you have inflammation under or on the back of your heel.

Last but not least, it is extremely important for patients and families to learn as much as possible about SpA. Although symptoms and the amount of inflammation may come and go with time and treatment, this is not a disease that can be cured at this time. Patients who cope the best and continue to function at a high level are those who approach maintaining physical activity as a lifestyle choice, and not simply depending upon disease therapy that can be attempted when symptoms worsen.

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What can I expect for the future?

Faced with a newly diagnosed chronic disease, most people want to know what the future will hold. In our experience this is one of the most difficult questions to answer because everybody is different. Making the correct diagnosis is very important since SpA is sometimes confused with JRA, and the outcome can be very different. Some studies where children with JAS were followed for about 15 years suggest they may not be able to accomplish as much as others their age. However, other studies have emphasized very positive outcomes with more than 75% of patients either employed or still taking classes, and only about 10-20% being disabled even after 20-30 years. The outcome is probably even more favorable for other SpAs, since JAS tends to be more severe. Given the early successes of treatment with biologics, the number of fully functional patients is likely to improve.

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Research Resources

Individuals who want more information about SpA or are interested in contributing to the genetic studies can contact the Spondylitis Association of America (SAA). For information try the SAA web site (http://www.spondylitis.org/), email (info@spondylitis.org), or call Toll-free (US Only) 1-800-777-8189. The regular number is: 1-818-981-1616. For research questions email (info@asresearch.org) or call toll-free (1-888-777-8189).

Table 1. Types of Juvenile Spondyloarthritis

• Juvenile ankylosing spondylitis (JAS)
• Undifferentiated spondyloarthritis
  • Seronegnative enthesopathy and arthropathy (SEA) syndrome
  • Enthesitis-related arthritis
• Reactive arthritis (ReA)
• Arthritis associated with Inflammatory bowel disease (IBD)
• Arthritis associated with Psoriasis

Table 2. Features exhibited by many patients with spondyloarthritis

Inflammatory spinal pain

Back pain developing before age 45 that is slow in onset, with symptoms improved by exercise and worsened by rest. This is accompanied by morning stiffness and generally must be of at least 3 months duration.

Synovitis

Inflammation of the synovium, or the layer of cells lining the joint space, which produces symptoms of arthritis; typically involving the lower limbs or shoulders in SpA.

Positive family history

Parents, sisters & brothers, grandparents, aunts, uncles or cousins with any of the following: AS, psoriatic arthritis, acute uveitis, reactive arthritis or inflammatory bowel disease with arthritis.

Psoriasis

Psoriasis is a skin disease that causes a scaly, pink rash in patches on the face, scalp and especially extensor surface of the joints.

Inflammatory bowel disease

Most often Crohn's disease or ulcerative colitis diagnosed by a physician.

Buttock pain

Past or current pain alternating between either buttock.

Enthesopathy

Past or current pain, or tenderness, where the Achilles tendon or plantar fascia insert on bone (back of heel or underneath heel). Enthesis is the general term for where a tendon or joint capsule inserts on bone, and enthesitis refers to inflammation at these sites.

Diarrhea

Abrupt onset of loose watery stool within one month prior to the onset of arthritis.

Sacroiliitis

Inflammation in one or both sacroiliac joints that is evident on X-rays.

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Table 3. Features distinguishing JRA from JSpA

Written 7/05

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