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Issue 1, Volume 5
Axial Spondyloarthritis (axSpA): Early and Differential Diagnoses

About the Author

5 Articles in this Series
Comorbid Pain in Axial Spondyloarthritis, including Fibromyalgia
Anatomical Distribution of Sacroiliac Joint MRI Lesions in Axial Spondyloarthritis and Control Subjects
Treatment of Axial Spondyloarthritis: What Does the Future Hold?
Understanding Barriers in the Pathway to Diagnosis of Ankylosing Spondylitis: Results From a US Survey of 1690 Physicians From 10 Specialties
Sex and Gender Differences in Axial Spondyloarthritis: Myths and Truths


Axial Spondyloarthritis (axSpA): Early and Differential Diagnoses

Axial spondyloarthritis (axSpA) refers to inflammatory/immune arthritis primarily affecting the spine. The prototype is ankylosing spondylitis (AS) but the classification also includes psoriatic arthritis and axSpA associated with inflammatory bowel disease (IBD). AxSPA is sometimes referred to as axial spondyloarthropathies.

Typically, the disease begins in the sacroiliac joints and gradually ascends up the spine. More than 80% of patients with axSpA present with signs and symptoms of inflammatory back pain, including morning stiffness > 30 minutes, pain that gets better with activity or exercise, and bilateral alternating buttock pain. Any patient under the age of 45 years presenting with more than 3 months of persistent low back pain should be suspected of having axSpA.

AxSpA takes longer to diagnose than any other rheumatic disease, with an average diagnostic delay of 7 to 10 years. Most clinicians are more alert to inflammatory back disease in patients with psoriasis or inflammatory bowel disease (IBD) or in any patient with extra-articular features, such as uveitis. Such extra-spinal features are seldom present in ankylosing spondylitis, which is one of the reasons that its diagnosis is especially delayed.

There are a number of reasons why the diagnosis of axSpA is so challenging:

1.     Chronic low back pain (CLBP) is ubiquitous; most often, there is no clear structural or inflammatory cause (referred to as non-specific CLBP). However, 10% to 20% of patients with CLBP have an inflammatory cause, usually axSpA. (See Inflammatory or Non-Inflammatory Chronic Back Pain)

2.     In contrast to patients with rheumatoid arthritis, most patients with axSpA have no obvious joint swelling. The physical examination is often unrevealing.

3.     AxSpA has traditionally been considered a male-dominant disease and the diagnosis in women has been especially problematic.

4.     The most helpful early diagnostic tests, the presence of HLA-B27 positivity and abnormal MRI of the sacroiliac joints, are not commonly ordered by non-rheumatologists.

The five papers chosen for this literature review primarily focus on the diagnostic challenges involved in axSpA. The first is an extensive survey of primary care providers and various specialists, including pain management clinicians, that aims to decipher the perceived barriers to making an accurate diagnosis of ankylosing spondylitis.

The second paper reviews the importance of gender in the diagnosis of axSpA, noting that the clinical presentation is much different in females, adding to diagnostic delays. The third discusses the non-inflammatory mechanisms that may cause pain in axSpA, particularly concurrent fibromyalgia. The fourth paper delves into imaging of the sacroiliac joints, highlighting a recent analysis that fine-tunes the interpretation of sacroiliac joint MRIs for a more timely diagnosis of axSpA. The last article discusses the potential future of axSpA therapy.

Many physicians are not aware of the major advances in the treatment of axSpA during the past decade. We now treat axSpA just like rheumatoid arthritis, beginning disease-modifying medications quickly, before irreversible damage ensues. Here, too, early diagnosis is essential for optimal outcome.

First Article:
Understanding Barriers in the Pathway to Diagnosis of Ankylosing Spondylitis: Results From a US Survey of 1690 Physicians From 10 Specialties
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