Managing ankylosing spondylitis

New recommendations for GPs from the National Ankylosing Spondylitis Society. By Dr Louise Warburton

All patients with AS need a specialist review to look for comorbities of the disease, such as spinal deformity (SPL)
All patients with AS need a specialist review to look for comorbities of the disease, such as spinal deformity (SPL)

The National Ankylosing Spondylitis Society (NASS) has recently produced a set of standards for best practice for managing patients with ankylosing spondylitis (AS).

AS is an inflammatory condition of the spine, which often produces pain, stiffness, deformity and disability throughout adult life.

It usually begins in adolescence or early adulthood, a critical period in terms of education, work and the establishment of social frameworks and relationships.

AS belongs to a group of rheumatic conditions characterised by inflammation in the spine, known as the spondyloarthropathies. Four distinct members of the spondyloarthropathies family are recognised: AS, psoriatic arthritis, reactive arthritis and enteropathic arthritis associated with inflammatory bowel disease.

Spondyloarthropathies may begin in childhood or the teenage years; juvenile spondyloarthropathies often present with uveitis, hip, knee and/or foot involvement. In many cases this does not evolve into typical AS.

Undifferentiated forms of spondyloarthropathies exist in adults and children, and these may or may not progress to a distinct form.

The prevalence of AS is 0.2-0.5% of the adult white population. It is likely that approximately 200,000 people have AS in the UK. The prevalence of spondyloarthropathies is similar to that of rheumatoid arthritis.

AS is a chronic progressive disease. It is characterised by periods of fluctuating intensity, leading to slowly increasing spinal and peripheral joint damage. Minimising the effects of disease progression and complications requires early recognition, careful long-term monitoring and prompt appropriate treatment. AS usually starts as inflammatory back pain.

Inflammatory back pain

The criteria for diagnosis of inflammatory back pain include back pain of more than three months' duration with:

  • Age at onset less than 40 years
  • Insidious onset
  • Improvement with exercise
  • No improvement with rest
  • Pain at night (with improvement on getting up)1

Inflammatory back pain is quite different from mechanical back pain. When assessing patients with inflammatory back pain, always ask about other important features in the history which may increase the likelihood of having a spondyloarthropathy, such as arthritis, enthesitis (commonly in the heel), uveitis, dactylitis (swelling of a whole digit such as finger or toe), psoriasis, Crohn's disease/colitis, or a family history of spondyloarthropathies.

Patients may or may not have a raised CRP; a positive response to NSAIDs is also part of the criteria for diagnosis of a spondyloarthropathy, as is HLA-B27 serology.

Sacroiliitis is part of the disease and is diagnosed by MRI scanning, which shows changes in the joints many years before X-ray changes become apparent.

Looking Ahead report

NASS has published a report on the treatment of patients with AS, Looking Ahead: Best practice for the care of people with ankylosing spondylitis.

The report concentrates on a few problematic areas in the diagnosis of AS and offers seven areas of recommendation.

Recommendations for AS by NASS

Recommendation 1

Back pain assessment pathways should include a system for the recognition of inflammatory back pain

Recommendation 2

Patients with suspected AS should be referred to a rheumatologist

Recommendation 3

The diagnosis of early AS/axial spondyloarthropathies should be made without waiting for X-ray changes: MRI is the investigation of choice

Recommendation 4

Patients with AS should have access to all appropriate specialists and treatments

Recommendation 5

Patients with AS should be made aware of the availability of anti-TNF therapy and offered treatment if eligible

Recommendation 6

Patients with severe spinal deformity should have access to expert surgical assessment and treatment

Recommendation 7

Patients with AS should be followed up regularly and have ready access to expert reassessment

Another area of concern is that the treatment of patients with AS varies considerably from one part of the country to the next.

Key points from the NASS report
  • AS usually starts as inflammatory back pain.
  • It can take up to 10 years for the features of AS to be evident on X-ray and therefore there is often a long delay in diagnosis.
  • Patients with inflammatory back pain who present to their GP or to musculoskeletal triage services can go unrecognised.
  • If a diagnosis of inflammatory back pain is made, the patient should be referred to a rheumatologist for further assessment.
  • GPs should be alert to the presentation of inflammatory back pain and treat this differently from mechanical back pain.
  • Early referral of these patients allows treatment to be commenced and reduces the likelihood of permanent spinal deformity.
  • Biological therapies, such as etanercept, are available and very effective in treating AS.

Management of AS

NSAIDs offer symptomatic relief. Exercise is extremely important and patients should have access to physiotherapy and hydrotherapy.

Patients who do not respond to these measures are now treated with anti-TNF drugs and these produce significant benefits.

Recent improvement in the treatment of AS makes it possible that GPs will see patients with AS who have not seen a rheumatologist for some time.

In the past, these patients were often discharged because not much could be done to help them, apart from arranging physical therapies.

We now recognise all patients with AS need a specialist review to look for comorbidities of the disease:

  • Osteoporosis and fragility fracture
  • Spinal deformities which could be amenable to surgery
  • Cardiac complications
  • Anaemia
  • Secondary osteoarthritis
  • Depression
  • Uveitis

Case study

Mr A, 26 years old, came to the surgery complaining of back pain. I noted that one of my colleagues had already referred him to the orthopaedic surgeons for the pain, which had started five years previously.

He had seen the orthopaedic surgeons and an X-ray at the time was normal, so he was discharged with advice and physiotherapy.

He was now experiencing pain in the thoracic region and lower back which was worse in the mornings, but also came back in the evenings when he was sitting down watching TV. Quite often he could not sleep due to the pain and found it difficult to turn over in bed. Thoracic back pain is a red flag symptom, so I was keen to examine Mr A.

He had quite a marked kyphosis and found it difficult to touch his toes. He also had difficulty bending sideways and his chest expansion was considerably reduced.

I requested a repeat X-ray and some blood tests. The blood tests were normal and the X-ray largely normal, but there was a suggestion of sacroiliitis.

For this reason, I referred Mr A to rheumatology, where an MRI showed definite sacroiliitis. He already had quite advanced spinal changes and thoracic kyphosis. Even if the X-ray had been normal, I would still have referred Mr A to rheumatology.

Twelve months later, he had failed to respond to conservative treatment measures, with physiotherapy and NSAIDs, and was commenced on etanercept.

This was immediately successful and Mr A managed to regain some of his spinal posture and carry on working as a butcher.

  • Dr Warburton is a GPSI in rheumatology in Telford, Shropshire, and a senior lecturer at Keele University.

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1. Sieper J, Rudwaleit M, Baraliakos X et al. The Assessment of SpondyloArthritis international Society (ASAS): a guide to assess spondyloarthritis. Ann Rheum Dis 2009; 68(Suppl II): ii1-ii44. doi:10.1136/ard.2008.104018.

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