Degenerative Disc Disease and AS

Ankylosing spondylitis (AS) and degenerative disc disease are both illnesses of the spine that share many of the same painful symptoms. Sometimes it is even hard for doctors to tell the 2 conditions apart. But even though they may look and feel similar, there are some important differences to keep in mind.

What is degenerative disc disease?

When you are young, rubbery discs between the vertebrae of your back allow you to twist and bend and give you height. These discs start to wear down as you age. By the time you are 40, you will most likely have some disc degeneration. But for some people, the disc fully wears away, causing bone to rub against bone. The result is pain and stiffness. There are a few causes of degenerative disc disease, also called spondylosis or osteoarthritis:^1,2

• Age-related disc dryness
• Tears on the surface of the disc from day-to-day activities
• Injury

Since there is not much blood supply to a disc in your back, it cannot repair itself if it is injured. The disc will then start to wear away for good.

You will usually feel the symptoms of degenerative disc disease in your lower back and neck. Pain ranges from mild to severe and may come and go. It could also spread to your buttocks, thighs, arms, and hands and get worse as you sit, bend, lift, or twist. Weakness in your leg muscles or trouble lifting the front part of your foot (called foot drop) could be a sign of nerve root damage.³

How are ankylosing spondylitis and degenerative disc disease similar?

AS and degenerative disc disease can look alike, even to doctors. They share many of the same symptoms and may even appear similar on images of the spine.

Both conditions cause:^1,4

• Pain in the lower back
• Pain that spreads to the neck and buttocks
• Pain that comes and goes

The illnesses may also look the same on X-ray and MRI images. Doctors use these screening techniques to look for changes to the spine linked to AS. But these changes could also look like degenerative lesions.

In fact, a 2018 study of X-ray and MRI images of people with each condition found that more than 70 percent who were thought to have AS actually had degenerative lesions of the spine. Researchers say with proper training, doctors can learn to spot differences in the 2 conditions.⁵

A different study also looked at the link between disc degeneration and AS. Researchers examined 1 group of people with AS and another without the condition. They found that disc degeneration was much higher in people with AS. This could mean that having AS could raise your risk of eventual disc erosion in your back.⁶

Here are some other research findings on the connection between AS and degenerative disc disease:⁶

• People with AS have a higher risk of hardened and narrow arteries (called atherosclerosis). This condition also plays a role in degenerative disc disease since arteries supply some blood to discs.
• Those with AS and degenerative disc disease may both have higher levels of enzymes involved in the breakdown of cartilage and tissue in bones.

How are AS and degenerative disc disease different?

Although these illnesses can look the same, there are some key differences:^1,4

• AS is caused by your genes and things in the world around you. Degenerative disc disease happens when 1 or more discs in your back wear down.
• Degenerative disc disease usually happens later in life, after age 40. AS typically appears between the ages of 17 to 45.
• AS pain is due to inflammation. Degenerative disc disease pain happens because of physical changes to the spine.
• Inflammation from AS can also cause other symptoms like a lack of energy, anemia, bowel problems, and eye inflammation (called iritis or uveitis).

How are AS and degenerative disc disease treated?

Treatment is different for AS and degenerative disc disease. Both conditions are treated with anti-inflammatory drugs, physical therapy, and lifestyle modifications like daily exercise, as tolerated. However, because AS is an autoimmune inflammatory condition, treatment typically includes the use of biologic drugs.

Surgical options vary for both AS and degenerative disc disease, as well. Those with degenerative disc disease may need surgery on the affected disc if the pain is severe. Surgery may be needed with AS, though it is not as common and usually involves hip joint replacement.