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The Patient With Spondyloarthritis
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The case: A 23-year-old man is being evaluated for a 9-month history of low back pain with prolonged morning stiffness. His symptoms tend to improve over the course of the day. He has used NSAIDs with only temporary relief. Past medical history is nonremarkable. He is taking no other medications. On physical examination, the low back and sacroiliac joints are tender to palpation with decreased flexion and loss of normal lumbar lordosis. Radiographs of the lumbar spine and sacroiliac joints are normal.
Key Supporting Information
Spondyloarthritis or spondyloarthropathy represents a family of inflammatory rheumatic diseases that cause arthritis. The most common is ankylosing spondylitis (AS), which mainly affects the spine. Others include:
- Axial spondyloarthritis (axSpA), which affects the sacroiliac joints, pelvis, and spine;
- Peripheral spondyloarthritis, affecting mostly the arms and legs;
- Reactive arthritis (formerly known as Reiter’s syndrome);
- Psoriatic arthritis; and
- Enteropathic arthritis/spondylitis, which is associated with inflammatory bowel diseases (ulcerative colitis and Crohn’s disease).
Axial spondyloarthritis comprises non-radiographic axSpA (nr-axSpA) and AS, the advanced stage of the disease. Failure to diagnose axSpA early and initiate treatment can result in progressive deformities of the axial skeleton and sacroiliac joints, resulting in loss of function. To decrease the delay in diagnosis and reduce loss of function and disability in patients with axSpA, primary care physicians (PCPs) must be able to recognize the difference between the inflammatory back pain (IBP) that occurs with axSpA and from the discogenic, osteoporotic and osteoarthritic back pain that can occur in the general population.
According to data from the National Health and Nutrition Examination Survey (NHANES), the prevalence of axSpA is between 1% and 1.4%, and the prevalence of AS is between 0.52% and 0.55% in the United States.
Patients with AS experience an average gap of 8 years to 11 years between the onset of symptoms and the time of diagnosis, resulting in delayed treatment and loss of function. Two main reasons for this lag in diagnosis exist. First, until recently the diagnosis of AS relied on the presence of radiographic sacroiliitis, which can take years to develop. The second reason is patients are not referred early enough to a rheumatologist by their PCP for appropriate diagnosis. The predominant symptom of axSpA is chronic lower back pain, which can be difficult for physicians to distinguish among the large number of patients they see with chronic back pain in general.
In order to decrease the delay in diagnosis and alleviate loss of function and disability in patients with axSpA, physicians must be able to differentiate between the IBP that occurs with spondyloarthritis and the osteoarthritic, osteoporotic and musculoskeletal back pain that can occur in the general population. Physicians also must be aware of the extra-articular manifestations of the spondyloarthropathies and understand the appropriate use of classification criteria and the importance of referral to a rheumatologist.
Inflammatory back pain is regarded as the most important symptom for identifying patients with axSpA. However, the use of lower back pain to diagnose axSpA is confounded by the high prevalence of chronic back pain in western industrialized countries. Recent data from NHANES suggest 19% of Americans experience chronic low back pain.
To help clinicians to differentiate between noninflammatory and inflammatory back pain, experts from the Assessment of SpondyloArthritis International Society have outlined criteria that can be used to define IBP in clinical practice. Patients who have experienced chronic back pain for more than 3 months and fulfill four of the following five parameters are thought to have IBP:
- age of onset younger than 40 years
- insidious onset;
- improvement with exercise;
- no improvement with rest; and
- pain at night (with improvement upon getting up).
In the diagnosis of axSpA, it is important that patients have experienced back pain for longer than 3 months because the acute back pain that occurs in a large portion of the general population normally resolves within 12 weeks. In patients with chronic back pain, the probability of having axSpA increases from 5% to 16% if the patient’s symptoms meet this definition of IBP. Although IBP has limited value for diagnosis of axSpA by itself, assessing whether IBP is present can be a feasible way to determine whether the patient needs a referral to a rheumatologist. In one study examining the use of IBP as a referral parameter, 35% of patients (n=322) referred to a rheumatologist with IBP were diagnosed with axSpA.
Among patients with chronic low back pain in primary care, the identification of individuals who are likely to have axSpA or AS and their subsequent referral to a rheumatologist for a correct diagnosis is critical to improve patient outcomes.
Since 1984, the modified New York criteria have been used to classify AS. They require the presence of radiographic sacroiliitis plus at least one of the clinical criteria. However, the inclusion of radiographic sacroiliitis results in a lack of sensitivity toward patients early in their disease course. Furthermore, radiographic sacroiliitis may take several years to develop in patients with AS, and treating patients earlier in the disease course recently has been shown to be more effective.
To standardize the definition of axSpA for the purpose of clinical trial research and increase the sensitivity for early nr-AxSpA, the ASAS developed and validated new classification criteria for axSpA. The classification criteria for axSpA are divided into two arms: the imaging arm and the clinical arm. The ASAS classification criteria apply to patients who are younger than 45 years who have had back pain for 3 months. Patients can be classified as having axSpA if they have sacroiliitis on imaging (magnetic resonance imaging [MRI] or radiograph) plus 1 or more of the features listed below, or if they are positive for HLA-B27 and have 2 or more of the other features listed:
- Inflammatory back pain
- Arthritis
- Enthesitis of the heel
- Uveitis
- Dactylitis
- Psoriasis
- Crohn’s disease or ulcerative colitis
- Good response to nonsteroidal anti-inflammatory drugs
Learning Objectives:
Upon successful completion of this educational activity, participants should be better able to assess ankylosing spondylitis.
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Overview
Author(s)/Faculty: Ronald A. Codario, MD, FACP, FNLA, RPVI, CCMEP
Source: Healio Rheumatology Education Lab
Type: Monograph
Articles/Items: 7
Release Date: 8/15/2015
Expiration Date: 8/15/2016
Credit Type: CME
Number of Credits: 1
Cost: Free
Provider: Vindico Medical Education
CME Information
Provider Statement: This continuing medical education activity is provided by Vindico Medical Information.
Support Statement: No commercial support for this activity.
Target Audience: This activity is designed for this activity is rheumatologists and other health care professionals involved in the treatment of patients with rheumatological disorders.