Axial spondyloarthritis: understanding inflammatory arthritis

Axial spondyloarthritis (AxSpA) is a type of inflammatory arthritis that affects the joints of the axial skeleton. The axial skeleton includes the bones that form the body’s vertical axis, which includes the bones of the face, jaw, skull, spine, and ribcage. AxSpA can also affect the sacroiliac joints, the joints that connect the spinal column to the pelvis.

There are two main types of this condition, ankylosing spondylarthritis and nonradiographic AxSpA:

• With ankylosing spondylarthritis, damage to the joints of the axial skeleton is visible on X-rays. This type is also known as radiographic AxSpA.
• With nonradiographic AxSpA, damage is not visible with an X-ray, but visible damage may be detected with magnetic resonance images (MRIs).

The most common symptom is pain in the lower back, buttocks, and/or hips. Typically, this pain gets worse at night, after sleep, and after periods of inactivity, and a person with AxSpA will feel back pain and stiffness in the morning.

Other symptoms can include fatigue, digestive problems, and loss of appetite. AxSpA can also cause pain, swelling, and/or redness in a variety of joints—in the hands, feet, legs, shoulders, upper spine, and/or neck. Typically, symptoms will be mild at first and get worse over time. Early symptoms may not be obvious or may be attributed to causes other than AxSpA.

In most cases, symptoms begin before age 30, and nearly all cases begin before age 45.

What is inflammatory arthritis?

Joint pain and other symptoms of AxSpA are the result of inflammation. Under normal circumstances, inflammation is a response to injury or infection—if you’ve ever had a sore throat when sick or the skin around a cut becomes swollen and tender, this is inflammation at work. It is the immune system flooding an area of the body with inflammatory chemicals, clearing out injured and infected cells, and healing damaged tissue.

AxSpA is characterized by inflammation caused by abnormal immune system activity. Instead of acting on injured or infected cells, the immune system releases substances that cause inflammation in the joints. The reasons why this occurs in some people are not fully understood and the causes of AxSpA are not fully understood.

Another key difference between the inflammation that occurs with AxSpA and normal inflammation—inflammation caused by a minor infection or injury is acute, while inflammation caused by AxSpA is chronic. Acute inflammation resolves within a short period of time. Chronic inflammation lasts for months, years, or indefinitely.

Over time, AxSpA inflammation can cause permanent damage to the joint tissues. This can lead to chronic pain, permanent loss of joint function, and in some instances, disability. This is what is meant when AxSpA is described as a progressive condition—it is a condition that tends to get worse over time.

For people with AxSpA, inflammation can affect other parts of the body. AxSpA is associated with other inflammatory conditions including inflammatory bowel disease, uveitis (an inflammatory eye disorder), and psoriasis. It is also associated with an increased risk of cardiovascular disease.

How is AxSpA treated?

There is no cure for AxSpA, but there are treatments that can help a person manage the condition. The main goals of treatment are to relieve symptoms, prevent the disease from getting worse, and stay as healthy as possible.

Treatment typically includes medications that reduce inflammation. In many cases, treatment begins with non-steroidal anti-inflammatory drugs (NSAIDs). If more aggressive treatment is needed, a person may be prescribed a tumor necrosis factor (TNF) blocker, interleukin-17 (IL-17) inhibitor, or a Janus kinase (JAK) inhibitors. These are drugs that act on specific substances in the immune system to reduce inflammation.

Physical therapy and exercise are also considered an essential part of a treatment plan for AxSpA, and can help with posture, range-of-motion, strength, proper sleep position, and movement. Surgical procedures (such as surgery to replace a damaged hip) may be needed in some cases, but this is not common.

If you or a loved one is living with AxSpA, your best source of information will be a healthcare provider.