Ankylosing spondylitis is a disorder that causes chronic pain in the joints, usually starting in the back and buttocks.

There are a few steps to diagnosing ankylosing spondylitis (AS), as well as some early signs that people should be aware of. People also need to understand how diagnoses can vary, and what sort of treatment they will receive.

The first thing that a doctor will want to do is ask the person about their health history. They will also ask a series of questions to find out what symptoms the person is experiencing. There are a few specific signs and symptoms that may point to the early signs of AS.

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While some back pain is triggered by an injury or heavy lifting, AS has no clear trigger.

Is there a family history of AS?

If there is a history of AS in a person's family, they are more likely to have the disease themselves, although this is not a guarantee. The doctor will still need to carry out thorough exams before making any diagnosis.

Does back pain have a known trigger?

Symptoms of AS, such as back pain and pain in the buttocks, will show up with no known cause.

For example, the person has not had an injury that can be linked to the pain, or no undue stress has been put on the back.

Are there any unexplained pains?

When people are young, they do not tend to experience odd pain or stiffness, which is why doctors look out for any unusual pains experienced by young people.

Some individuals with AS will not experience back pain at first but may experience a tight ribcage that makes it hard to breathe. Others may have stiff joints or pain in their ankles, or may even experience inflammation in their wrists.

The pain behaves in much the same way no matter where it is located in the body, however.

Did the pain gradually get worse?

Another sign of AS is that the pain gradually gets worse, often over the course of a few months or more.

What may start as a very slight stiffness can gradually grow into aching, stiff joints, and a rigid-feeling spine as the disorder progresses.

Is the pain worse when sleeping or prone?

With many conditions, chronic back pain gets better when resting. The opposite is true with AS. People who have AS will experience more pain when resting or sleeping. The pain gradually gets better as they move around throughout the day.

Does the pain get better with physical motion?

The pain caused by AS is also different from other types of back pain because exercise makes it better, not worse.

Exercise and stretching can irritate other people with back pain, but someone with back pain caused by AS will feel relief after stretching or doing other forms of exercise.

Do NSAIDs treat the pain?

In the early stages of AS, over-the-counter drugs such as ibuprofen will ease the pain, but it does little to deal with the disorder. However, if a person's symptoms get better with non-steroidal anti-inflammatory drugs (NSAIDs), it is likely that they have AS.

Are there any other symptoms?

There are other symptoms associated with AS, including inflammation of the eye, a history of gut disorders, or general tiredness. Knowing if a person has any of these symptoms helps a doctor decide whether they have AS.

Doctors will often ask these questions to find out if they should continue to the next step of diagnosing AS, which is usually a physical exam.

Doctors diagnose AS using a few different methods. No single test can tell doctors if someone has AS, so they piece together information from a few different areas.

Blood tests

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A doctor will do a range of tests to determine whether a person has AS.

There is one specific blood test associated with AS. It is called the HLA-B27 test, and it tests for the HLA-B27 gene. People with this gene are more likely to have AS. It is not always the case, however, and there are many people with the gene who never develop AS.

Doctors may also try other blood tests that look for marks of inflammation in the body, such as the ESR level or the CRP. These tests can spot common signs of inflammation in the body, but again these are not only caused by AS.

These blood tests are used to give doctors a better picture of the person's health.

Physical exams

During the physical exam, the doctor will usually check for signs of inflammation in the person's body. Typically, a doctor will look at the back, chest, pelvic bones, sacroiliac joints near the bottom of the spine, and heels of the feet.

They will often gently press into these areas and ask about any pain and tenderness felt. Doctors may also ask people to do some quick mobility tests to see if their spine or chest is restricted in any way.

Imaging and scans

After looking for signs in the blood, doctors will often use X-rays, MRIs, or CT scans to check on the bones and joints. They are looking for signs of inflammation, such as widening or thinning space between bones, and may focus on the sacroiliac joints, where AS is known to appear.

Imaging will usually confirm the presence of AS. This will help doctors to track its progression, and recommend treatment options.

Differences in diagnoses

Men and women both experience AS, though it appears to be more common in men. Symptoms may show up in childhood, though most diagnoses of AS occur between the teenage years and the age of 30.

Pregnant women who have AS may have difficulty giving birth, as inflammation in the spine and hips can make an epidural shot problematic. Pregnant women with AS may have to be put under anesthesia during delivery, though it will not directly affect their pregnancy or unborn child.

When to see a doctor

People should see a doctor if they feel that they have any symptoms that are similar to the early signs and symptoms of AS. Slowing the progression of AS and managing symptoms is possible in most cases, but it does require medical attention.

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Treatment will focus on slowing the progression and reducing the symptoms of AS.

Treatment for AS involves reducing the symptoms of inflammation while slowing the progression of the disorder. Treatment plans will typically include using NSAIDs to control pain and inflammation, and may include drugs known as TNF-a inhibitors to slow the progression of the disorder.

Exercise and flexibility can play a major role in reducing symptoms in many people. Doctors will probably include physical therapy, exercise, and techniques to correct posture in a treatment plan.

Breathing exercises can help to expand the chest. Many people will also be encouraged to take up low-impact, full body workouts, such as swimming and cycling. A varied treatment plan is essential for keeping AS in check.

AS is a type of arthritis which most commonly causes back pain. It is not caused by physical trauma or injury but is a chronic disorder caused by inflammation of the spine and joints. Once diagnosed, AS often lasts for a person's entire life.

The disorder occurs in both men and women of all ages. A recent study posted to Arthritis Research and Therapy noted that the first symptoms of AS usually show up before the age of 30, and rarely occur after the age of 45.

The disorder can affect a person's ability to function in their daily lives, disrupt their ability to work, and can significantly reduce how they view their quality of life.

AS progresses differently in each person, some people experience mild symptoms all of their lives that progress slowly while other progress quickly.

Some cases lead to ankylosis, which is the creation of new bone. In AS, this happens when two or more bones in the spine fuse together or the sacroiliac joint becomes fused. Some cases of AS can even lead to disability.

Diagnosing the disorder correctly and taking steps to treat the symptoms is vital for people managing AS.