Ankylosing Spondylitis, or AS, is a form of arthritis that primarily affects the spine, although other joints can become involved. It causes inflammation of the spinal joints that can lead to severe, chronic pain and discomfort. AS can also cause inflammation, pain and stiffness in other areas of the body such as the shoulders, hips, ribs, heels and small joints of the hands and feet. These changes may be mild or severe, and may lead to a stooped-over posture. Early diagnosis and treatment helps control pain and stiffness and may reduce or prevent significant deformity.
Ankylosing spondylitis affects about 0.1% to 0.5% of the adult population. Although it can occur at any age, spondylitis most often strikes men in their teens and 20s. It is less common and generally milder in women.
Although the cause of anklosing spondylitis is unknown, there is a strong genetic or family link. Most, but not all, people with spondylitis carry a gene called HLA-B27. Although people carrying this gene are more likely to develop spondylitis, it is also found in up to 10% of people who have no signs of the condition.
Early signs and symptoms may include pain and stiffness in your lower back and hips. These symptoms may come on so gradually that you don’t notice them at first. Over time, symptoms may worsen, improve or stop completely at irregular intervals. The areas most commonly affected are the joints between the base of your spine and pelvis, vertebrae in lower back, cartilage between your breastbone and ribs, hip and shoulder joints. Ankylosing spondylitis is a systemic disease, which means symptoms may not be limited to the joints. People with the condition may have fever, fatigue, and loss of appetite.
Diagnosis of ankylosing spondylitis may be delayed if your symptoms are mild or if you mistakenly attribute some of your symptoms to more common back problems.
- Medical history - The doctor will ask the patient about their pain, whether they have any other medical conditions and if any family members have back problems or arthritis.
- Physical exam - The doctor will check if the patient has any pain along the spine and/or pelvis, sacroiliac joints, heels or chest. The patient may also be asked to move and bend in different directions to check the flexibility of the spine.
- X-ray - X-rays allow your doctor to check for changes in your joints and bones, though the characteristic effects of ankylosing spondylitis may not be evident early in the disease.
- Magnetic resonance imaging (MRI) - Using radio waves and a strong magnetic field, MRI scans are better at visualizing soft tissues such as cartilage.
- Blood test - The main blood test used checks for the HLA-B27 gene. This gene is not always present in people with AS. Less than 8 percent of Americans that have the gene actually develop AS. If the gene is present in someone that has symptoms of AS, it may help support the diagnosis of AS. Certain blood tests can check for signs of inflammation, however inflammation can be caused by many different health problems.
There is no cure for AS, but there are treatments that can reduce discomfort and improve function. The goals of treatment are to reduce pain and stiffness, maintain good posture, prevent deformity, and preserve the ability to perform normal activities. Under ideal circumstances, a team approach to treat spondylitis is recommended. Members of the treatment team typically include the patient, doctor, physical therapist, and occupational therapist.
Doctors use a variety of approaches to treat AS that are often used in combinations. The most commonly used treatments are:
- Nonsteroidal anti-inflammatory drugs (NSAIDs) — these medications are commonly used to relieve pain and inflammation. Some people seem to respond better to one NSAID than another. Examples of NSAIDs are aspirin, ibuprofen and naproxen.
- Disease-modifying anti-rheumatic drugs (DMARDs) — these medications help control the disease process and help reduce inflammation. The most commonly used DMARD for AS is sulfasalazine.
- Corticosteroids — Injections of corticosteroids directly into the affected joint can offer quick but only temporary pain relief. Injections may be given in the sacroiliac joint, hip joint or knee. They cannot be given in the spine.
- Biologic agents — this class of medications helps relieve symptoms when NSAIDs or other treatments have not worked. They are given by infusion or injection.
Sometimes side effects can disrupt a person’s life and day-to-day activities. However, it is important that a person never change their dosage or stop taking their medication without talking to their doctor or pharmacist.
Common side effects for the different treatment options for AS include:
- NSAIDs - Nausea, vomiting, heartburn, diarrhea and headache
- DMARDs - Nausea, vomiting, diarrhea, weakness, liver damage and increased risk of developing an infection
- Corticosteroids - Weight gain, increased appetite, anxiety, nervousness and increased risk of developing an infection. Steroids may also interfere with normal growth in children.
- Biologic agents - Cough, nausea, vomiting, rash, weakness, abdominal pain and increased risk of infection