Diagnosing Chronic Back Pain: When to Suspect Axial Spondyloarthritis

Sara Freeman

August 11, 2023

Primary care practitioners have an important role to play in helping to diagnose people with axial spondyloarthritis (axSpA) much sooner than is currently being achieved, according to several experts who are championing the need for the earlier diagnosis of the condition.

AxSpA is an inflammatory condition of the spine and joints that often goes undiagnosed for many years. Worldwide, the average time to diagnosis was found to be up to 6 years in a recent systematic review. But patient advocacy groups in both the UK and US say that the delay can be much longer, possibly up to 10 years or more.

Being Aware Is Key

"We know people get significant pain and functional difficulties if it's not picked up early, and that impacts on patients financially," said Toby Wallace, MBChB, a general practitioner based at the Derwent Practice in Malton,North Yorkshire, England, and one of 12 Champions in Primary Care for the National Axial Spondyloarthritis Society (NASS) in the UK.

Being aware of the condition is vital to improving the time to patients getting diagnosed and treated, Wallace told Medscape Medical News. The quicker patients can be identified and referred onward on to a specialist rheumatology colleague means the sooner they will receive the appropriate care.

Chronic Back Pain

One of the key symptoms of axSpA is back pain, said Wallace. Back pain is an "extremely common" symptom seen in primary care — an estimated 60% or more of adults will have a back problem in their lifetime — but with axSpA, "it's more about it being a persistent pain that is not going away."

Fellow NASS Primary Care Champion and advanced practice physiotherapist Sam Bhide, MSc, calls them the "frequent flyers."

As a first-contact practitioner, much of her practice consists of seeing people presenting with back pain, many of whom may have already been seen by other professionals but diagnosed with mechanical back pain.

"These patients return due to lack of improvement in their ongoing back pain symptoms," Bhide noted. But how do you know if it is axSpA causing the pain?

"Normally, we would look for people who have had back pain for more than 3 months, or that gradually progresses on and off over weeks, months, or years, and their symptoms ease but do not resolve completely," she said.

Eased by Exercise and Medication

"Essentially we are looking for people with inflammatory back pain," Bhide explains.

The pain is often eased with anti-inflammatory medication and with exercise, "which is why these people get missed because they are managing their symptoms with exercises and their anti-inflammatories," she said.

Sleep Disturbance and Morning Stiffness

Sleep disturbance and feeling stiff in the spine for at least 30 minutes upon waking in the morning are other big indicators that chronic back pain may be due to axSpA, Wallace said.

"Waking in the early hours of the morning with pain or stiffness and having to get up and move around is fairly usual."

Signs and Symptoms
  • Age < 45 years

  • Chronic back pain (3+ months)

  • Morning stiffness (> 30 minutes)

  • Improvement with exercise, not rest

  • Responds to anti-inflammatory medications

  • Night awakenings due to pain

  • Alternating buttock pain

  • Enthesitis and tendonitis

  • Swollen fingers (dactylitis)

Aged Under 45 Years

AxSpA typically occurs in younger people, but it can be diagnosed at a later age, said Raj Sengupta, MBBS, a consultant rheumatologist and clinical lead for axSpA at the Royal National Hospital for Rheumatic Diseases in Bath, England.

"In someone who's under the age of 45, if they've had more than 3 months of back pain, then you should be thinking about axial spondyloarthritis already," he said.

"The proviso is that in someone who's older, actually asking them when their back pain started is relevant, because that person may have had symptoms that started at age 20, but for whatever reason, they didn't seek help," said Sengupta. "They could still have undiagnosed axial spondyloarthritis."

Women Can Be Affected As Much As Men

Importantly, it appears that women can be just as affected as men, particularly in the early stages of the disease, said Sengupta.

"In the old days, people just thought of it as a 'men-only' disease, but what we've learned is that the earlier stage of the disease, the prevalence is much more 50:50," he said.

"The sad part is that over the years women have been really underdiagnosed because of this false message that has gone about, saying women can't get it. So, sadly, you see greater delays in diagnosis in women because of that."

Other Symptoms and Associated Conditions

In people with early axSpA, "pain tends to be over the sacroiliac joints, which is over the buttocks, so it's often confused with sciatica," explains Sengupta. Alternating buttock pain is something to take note of, as is tendonitis and enthesitis. The latter is inflammation where the tendons or ligaments are inserted into bone, so it means that people may have problems such as Achilles heel, tennis elbow, or even musculoskeletal chest pain. Dactylitis — swollen fingers or toes — is another sign seen in some people with axSpA.

Associated Conditions (Including Family History)

  • Psoriasis

  • Inflammatory bowel disease

  • Eye inflammation (uveitis or iritis

"Family history is also really important," although not essential, Sengupta said. And not only if there is axSpA in the family, but also if there are other conditions such as psoriasis or inflammatory bowel disease. Another commonly associated condition is eye inflammation, which can be uveitis or iritis.

What About Tests and Tools?

Testing for HLA-B27 — which has a known association with axSpA — and measuring blood levels of C-reactive protein may be helpful, but "even if they are normal, that shouldn't be reassuring you that this can't be ankylosing spondylitis [in a patient with a] strong inflammatory back pain story."

Ordering an MRI scan may be possible within primary care, depending on where you are in the world, but the results do need to be interpreted with expert eyes, Sengupta advises.

There are online tools available to help with the diagnosis of axSpA, Sengupta said, such as the Spondyloarthritis Diagnosis Evaluation Tool (SPADE). Efforts are also underway to create online systems that help to flag symptoms in general practice.

Tests and Tools

  • HLA-B27 association

  • Elevated C-reactive protein

  • Sacroiliitis on MRI

  • SPADE Tool

The bottom line is that many more patients could potentially be identified earlier in primary care by careful assessment of the clinical symptoms and asking about the family history and associated conditions.

At its simplest, if you see "someone under the age of 45, if they've had 3 months of back pain, and they keep on coming back to say, 'My back's really bad,' think about axial spondyloarthritis," said Sengupta.

Sara Freeman is a medical journalist and freelance medical writer based in London, England.

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