Could That Back Pain Be Ankylosing Spondylitis?

Most of us have back pain at some point—90% of us, in fact—and it has lots of potential causes. Ankylosing spondylitis is one of them. Here’s how to know if AS might be behind yours.

by Stephanie Stephens Health Writer

Tema Smith, 36, was living with ankylosing spondylitis (AS) for 20 years—yes, really!—before she even had a clue what the condition was. When she was 12, Smith experienced what she now knows was her first flare from juvenile-onset AS.

From then on, for literally the next two decades, pain and fatigue would come and go, but they were always easily passed off as symptoms of something else:

  • That pain in her feet, ankles, hips, and legs? Of course they hurt, she worked on her feet all day and was accident prone.

  • The wrist and finger pain? She did spend a lot of time writing and playing her violin.

  • Feeling beyond exhausted? She'd been diagnosed with hypothyroidism and then there was the bout of mononucleosis—hello, fatigue!

  • And that low-back pain? It seemed so run-of-the-mill—until one day it really didn’t.

Smith, who lives in Toronto, had major flares of these symptoms at ages 17, 25, 27, 29, and finally, “the flare of flares” at age 32. That’s when she knew something was clearly wrong. She remembers being in tears from both the pain and the frustration of not know what caused it. She saw her doctor, who promptly referred her to a rheumatologist. That specialist said within 10 minutes of her visit: “I think you have AS.” Three months later, test results confirmed it.

AS is a systemic chronic disease that causes pain and inflammation primarily in the spine and sacroiliac (SI) joints, which connect the spine to the hips. AS can also affect organs, such as the eyes, heart, and lungs. There isn’t a cure for the condition—at least not right now—but getting the right medications and therapy started ASAP can not only improve your pain and symptoms, but it can also prevent long-term complications and joint damage. Some studies show treatment can also slow disease progression.

So how do you know if your persistent pain is AS or something else? Let’s dig into the differences between more the more common type of back pain—mechanical—and back pain that might signal something deeper is going on.

The Causes of Mechanical Back Pain and AS Are Different

If you have back pain, you have plenty of company. Up to 90% percent of Americans have some form of acute back pain in their lifetime—meaning pain that lasts up to six weeks—says rheumatologist Fardina Malik, M.D., an instructor in the department of medicine at New York University’s Langone Health in New York City. Mechanical back pain is usually caused by a degenerative process in the joints or discs around the spine, Dr. Malik says.

That can include structural changes to discs, bones, and soft tissue, such as muscles and ligaments, says Lynn M. Ludmer, M.D., medical director of rheumatology at Mercy Medical Center in Baltimore.

What causes routine back pain? Many things, including:

  • Doing too much, resulting in a ligament sprain or tendon or muscle strain

  • Radiculopathy, which occurs when a spinal nerve root is injured. Sciatica is a form of radiculopathy that occurs when the sciatic nerve in the buttocks and back of the leg is compressed.

  • Spondylolisthesis (don't bother trying to pronounce it!), which occurs when a lower-spinal vertebra slips out of place. According to Penn Medicine, this isn't the same as the term "slipped disc," which usually refers to a disc between the vertebrae moving out of place or rupturing.

  • A traumatic injury

  • Spinal stenosis or narrowing of the spinal column

  • Skeletal irregularities of the spine, like scoliosis, which causes the spine to curve

AS, on the other hand, is caused by out-of-control inflammation—no injuries, muscle pulls, or lifting heavy boxes. Estimates say AS may affect approximately 1% of American adults. It’s unclear what triggers the inflammatory response in the first place, but genetics play a role. More on that in a bit.

The Symptoms of Mechanical Back Pain and AS Are Different

According to the Cleveland Clinic, symptoms of mechanical back pain may include:

  • Muscle spasms

  • Pain that radiates to the thighs or buttocks

  • Pain that occurs mostly in the lower back

  • Pain that seems most noticeable when you flex your back or lift heavy objects

While some symptoms may seem to overlap, the signs of AS are pretty distinct once you know what you're looking for. First and foremost: “Chronic back pain lasting three or more months that's caused by inflammation could be ankylosing spondylitis,” says Dr. Malik. So, think about your back pain for just a sec. It could be AS if:

  • Your pain began at a relatively young age, typically before age 45. Smith is among the 10% to 20% of AS patients who develop symptoms before age 16.

  • You wake up several times during the night with back pain, and then it's really hard to go back to sleep.

  • You wake up in the morning feeling very stiff—it's the worst time of your day.

  • Your lower back and buttocks may hurt first, and discomfort can switch from one side of the body to the other and back again.

  • Your pain actually gets worse with rest. But if you start walking or stretching, usually after 45 minutes to an hour, your back pain gets better and you might even forget you woke up miserable as your day goes on.

  • You also have irritable bowel disease (IBD), psoriasis, or uveitis—a type of eye inflammation.

  • You have tightness in your ribcage making breathing difficult.

AS, mainly affects the spine, but beyond that, the disease:

  • Can affect hips, ribs, shoulders, knees, and feet

  • Can also affect organs, such as the eyes, heart, and lungs

  • In severe cases, bone spurs can fuse the spine into an inflexible column.

The Path to Diagnosis Is the Same (to a Point)

When you visit your doctor for back pain, the first step will be a physical examination and discussion of your symptoms. Don’t expect any blood work to rule out a potential underlying disease like AS right away. You may not even get any imaging tests either. It isn’t realistic to do imaging on every patient who comes in with back pain.

“We try to narrow it down to patients with chronic back pain and other clinical features that raise suspicion for AS,” says Dr. Malik. “A chronic low-back pain patient whose images don't show SI joint issues may have another cause of back pain.”

If your doctor suspects you've got something other than mechanical back pain going on, they’ll refer you to a rheumatologist who specializes in AS or arthritis. If you don’t get a referral, but think you need one, Dr. Ludmer says it’s important to speak up.

“Since it is uncommon, some primary care physicians do not think about the AS diagnosis in patients with chronic back pain and overlook clues to that diagnosis,” says Dr. Ludmer. “If a physician is not taking a patient's complaints seriously, they may need to find another physician.”

If your rheumatologist thinks you might have AS, they will:

  • Take your medical history and ask you about family history: Any history of AS or autoimmune diseases in other family members?

  • Do an overall physical exam.

  • Do blood work. This could include measuring C-reactive protein (CRP) and erythrocyte sedimentation rate (SED), which both indicate inflammation when elevated. A genetic test can also look for HLA-B27, but its presence is only an indicator, not a “for sure.” Though not often tested, genes IL23R and ERAP1 also raise the chance of developing AS, according to the National Institute of Arthritis and Musculoskeletal and Skin Diseases (NIAMS), so they're not a "for sure" either.

  • Perform imaging, such as X-ray, CT scan, or MRI to assess bone and joint health. Rheumatologists look closely at the spine and pelvic area, in particular the SI joint.

Smith's blood work, for example, showed high inflammation and that she had the HLA-B27 gene. Her MRI revealed sacroiliitis—an inflamed SI joint—and some swelling in her spine.

“Since AS has strong genetic links, having a family history of the disease can be a strong clue,” Dr. Ludmer says. “HLA-B27 can be helpful in considering the diagnosis, but the majority of people in the United States with this gene do not have AS, so its presence needs to be considered in the context of other features.”

Treatments AS and Mechanical Back Pain Vary

For mechanical back pain, the type of treatment you’ll get depends on what’s causing the pain. Some issues will resolve with rest and over-the-counter pain relievers, while other issues may require prescription medications, injections, or even surgery.

For AS, treatments typically include:

  • Nonsteroidal anti-inflammatory drugs (NSAIDs). These include aspirin, Advil (ibuprofen), Aleve (naproxen), or Cambia (diclofenac). Patients who use NSAIDs have been shown in studies to have less X-ray damage over time. NSAIDS are also used as remedies for other back pain, but the doses needed to treat AS may be higher since AS has an inflammatory basis compared to mechanical back pain. Dr. Ludmer points out that people with AS shouldn’t dismiss the role of NSAIDs as an initial treatment to help with symptoms of joint pain and stiffness.

  • Biologics, such as a tumor-necrosis factor (TNF) blocker or interleukin-17 (IL-17) inhibitor, work similarly to block the proteins that fuel inflammation. For AS patients who continue to have symptoms despite high-dose, continued NSAIDs, biologic medications really can be help, Dr. Ludmer says. They target proteins the body produces during an inflammatory response. FDA-approved TNF inhibitors include Humira (adalimumab) and Remicade (infliximab); Cosentyx (secukinumab) is an IL-17 inhibitor.

  • Physical therapy to help relieve pain and increase strength and flexibility, as well as maintaining motion, Dr. Ludmer says.

  • Surgery for severe pain or joint damage, sometimes to replace hip joints. A laminectomy to remove bone over the spinal canal may be done if fractures put weight on the spinal cord and adjacent nerves. Surgery is usually discussed if previous treatment options haven't provided enough relief. The idea, as always, is to ensure the best quality of life with a condition like AS.

Dr. Ludmer cautions that “AS does not come in one size. We do not know how to predict who will go on to do permanent damage, but joint replacements in hips and shoulders are not uncommon as is loss of motion in the all areas of the spine. The damage may be slow and difficult for patients—and physicians—to detect.”

That's why early detection and treatment is so important. Jed Finley, a special-education teacher from St. Louis, was diagnosed at age 12 with AS. Now 38, Finley considers himself lucky to have gotten a diagnosis so early in life so he could begin treatment. He shares this message with anyone who suspects AS may be causing their back pain: “If you have back pain that you know isn't normal, don't let your doctor leave the room until you are satisfied because they can't get a good understanding of a patient in just five minutes.”

Finley and Smith are great examples of “if you feel something, say something.” And in Smith's case, keep saying something. If your back pain isn't getting better, and you suspect it's something more, listen to your body, and talk to your doctor.

  • Ankylosing Spondylitis: The Arthritis Foundation. (n.d.).
  • Primer on Ankylosing Spondylitis (1): National Institute of Arthritis and Musculoskeletal and Skin Diseases. (n.d.).
  • Primer on Ankylosing Spondylitis (2): Mayo Clinic. (n.d.). "Ankylosing Spondylitis."
  • Primer on Ankylosing Spondylitis (3): The Spine Hospital. (n.d.).
  • Juvenile Spondyloarthritis: Spondylitis Association of America. (n.d.). "Overview of Juvenile Spondyloarthritis."
  • Ankylosing Spondylitis and Spondyloarthropathy: Medscape. (2019) "How does the prevalence of ankylosing spondylitis (AS) and undifferentiated spondyloarthropathy (USpA) vary by age?"
  • Spondylolisthesis: Penn Medicine. (2017). "What Does Your Spondylolisthesis Diagnosis Mean?"
  • Mechanical Back Pain: Cleveland Clinic. (n.d.). "Acute Mechanical Back Pain."
  • Spondyloarthritis and Gender: The Journal of Rheumatology. (2017). “Understanding How the Diagnostic Delay of Spondyloarthritis Differs Between Women and Men: A Systematic Review and Metaanalysis."
  • Axial Spondylarthritis Prevalence: Arthritis Care & Research. (2014). "Prevalence of Axial Spondylarthritis in the United States: Estimates from a Cross-Sectional Survey."
  • Chiropractic and Ankylosing Spondylitis: American Chiropractic Association. (2016). "Chiropractic and Ankylosing Spondylitis."
  • Ethnicity and Disease Severity in Ankylosing Spondylitis: Clinical Rheumatology. (2017). "Ethnicity and disease severity in ankylosing spondylitis: a cross-sectional analysis of three ethnic groups."
Stephanie Stephens
Meet Our Writer
Stephanie Stephens

Stephanie Stephens is a very experienced digital journalist, audio/video producer and host who covers health, healthcare and health policy, along with celebrities and their health, for a variety of publications, websites, networks, content agencies and other distinctive clients. Stephanie was accepted to THREAD AT YALE for summer 2018 to author and produce an investigative series. She is also active in the animal welfare community.