Spondyloarthritis, Spondyloarthropathies, SpA 4.5/5 (8)

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Spondyloarthritis (Spondyloartropathies, SpA)


Back pain, including in the iliosacral joints, is typical of spondyloarthritis

Spondyloarthritis is a group of rheumatic autoimmune (inflammatory) diseases that affect joints and back. Some related complications (eyes, joints, tendons, skin, blood vessels, gut) can sometimes resemble Systemic connective tissue diseases: og Vasculitis.

Classification criteria (see below) distinguish between "radiological" SpA and "non-radiological" SpA. The classification criteria are designed to be able to compare fairly similar cases of disease in research and quality studies.

  • These criteria easily lead to over-diagnosis and are not recommended in practice to diagnose, although they contain many typical features of the disease

Authorities in Norway (NAV / HELFO) often require that classification criteria are met before benefits (drugs on a «blue prescription», social security) are given. 


It is estimated that 0,5-1% of the population has spondyloarthritis, of which Ankylosing spondylitis and psoriatic arthritis make up the majority of cases. The part of the incidence caused by Ankylosing spondylitis is highest in the far north (where the hereditary factor HLA-B27 is most common).

Classification of SpA according to ASAS criteria

(reference: Rudwaleit M, 2009)

1. Prerequisites

  • Age at start of symptoms is less than 45 years
  • Inflammatory back pain present (see section "Symptoms" below)
  • SpA is divided into two main groups:
    • Radiological sakroiliitt (on CT or X-ray images) + one SpA item (see below). Radiological SpA is largely identical to Bekhterev's disease (ankylosing spondylitis)
    • Non-Radiological SpA: HLA B27 (hereditary predisposition, detected in blood) or inflammation (inflammation) in sacroiliac joints by MRI examination + least Two SpA items (see below)
      • Non-radiological SpA can have different courses
        • An early form of radiological SpA or:
        • A milder type with better prognosis

2.SpA items/findings

The ASAS criteria originally intended to capture patients early after the onset of disease. However, diagnosing early causes an increased risk of someone being diagnosed incorrectly. One must pay special attention to the following

  • Only 30% with inflammatory back pain develops spondyloarthritis (reference: Wang R, 2018), in some studies even fewer
  • After physical training and among some others who are healthy, MR images show changes that can be misinterpreted as inflammation (reference: the winter J, 2018)


Arthritis in a few large joints (knees, ankles, hips)


Swollen and hot knees occur at Spondyloartritt

Inflammatory back pain which has lasted at least 3 months

  • Morning stiffness in the back for at least 30 minutes
  • Improvement by physical activity, not to be at rest
  • Wake up in the second half of the night because of pain
  • Alternating pelvic pain (gluteal)

Other symptoms

  • Heel pain with signs of inflammation (entesitis)
  • Joint inflammation (arthritis) in major joints
  • Swollen fingers or toes (dactylite)
  • Eye inflammation in the form of acute uveitis / iridocyclitis
  • Good effect of NSAIDs (Ibux, Voltaren and others)

Medical examination

Clinical examination

  • Arthritis in large joints
  • Reduced movement in the back
  • Inflamed Achilles tendons, tendon attachments or plantar fascia (enthesitis)
  • Psoriasis
  • Bowel disease (Ulcerative colitis, Crohn's disease)
  • Eyes with redness or uneven pupils

Blood tests

  • Elevated tests for inflammation (CRP, ESR)
  • HLA B27 present (25-95%, against 8-16% in the population)


  • MRI, CT or X-ray examinations
    • The radiographs show signs of inflammation in sacroiliac joints (Between pelvic and spinal cord)
    • Inflammatory changes in the spinal column
    • MRI images can easily be misinterpreted (please see below)


Made based on symptoms and examination findings

  • The tissue type HLA-B27 occurs in approx. 8% in the population of Southern Norway and twice as often the furthest north in Norway and alone is not a criterion for the diagnosis
  • MRI examination of iliosacral joints may show changes earlier than CT and X-ray examination
    • "Usures" in the joints are inflammatory changes in the cartilage and bone substance that usually persist
    • MRI changes that show "edema" is an uncertain finding that can go back and is not necessarily caused by rheumatic inflammation.
    • When different specialists interpret the same MRI images of the iliosacral joint at «non-radiographic SpA», they disagree / come to a different conclusion in about one in three cases

Incorrect diagnosis (similar conditions, differential diagnoses)


Physical therapy, self training and symptomatic medications like NSAIDs (for example Voltaren / diclofenac) is the basic

  • NSAID reduces pain and improves physical mobility. It is discussed whether or not disease development (on radiological images) is also reduced
  • Some people need disease-suppressing add-on that can also include Biological treatment with TNF inhibitors
    • TNF inhibitors reduce symptoms and improve mobility. There are indications that also the disease development (on radiological images) is inhibited

Guidelines and recommendations

 EULAR: van der Heijde D, 2016 (Treatment)

Norwegian Rheumatological Association / The Norwegian Medical Association (Axial spondyloarthritis)


Ankylosing spondylitis

Psoriatic arthritis

Rheumatic manifestations at Ulcerative colitis and Crohn's disease

Reactive arthritis

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