Spondyloarthropathies / Ankylosing spondylitis

Axial spondyloarthritis (axSpA) is a chronic inflammatory disease that affects the axial skeleton, mainly the spine and sacroiliac joints. The condition encompasses both non-radiographic axial spondyloarthritis (nr-axSpA) and radiographic axial spondyloarthritis (r-axSpA), which was previously referred to as ankylosing spondylitis (AS). In this essay, we will discuss the diagnosis, phenotypes, and treatment of axSpA in detail.


The diagnosis of axSpA can be challenging and may require a combination of clinical, laboratory, and radiographic assessments. The following are the diagnostic criteria for axSpA:

Clinical features: The presence of chronic back pain, which lasts for at least three months, and is worse in the morning and improves with exercise, is the hallmark symptom of axSpA. Other clinical features include stiffness in the back, limited spinal mobility, and peripheral arthritis.

Imaging: Radiographic evidence of sacroiliitis is the most specific feature of axSpA. Magnetic resonance imaging (MRI) can detect early changes of sacroiliitis, even before radiographic evidence appears. Other imaging features include bone marrow edema and syndesmophytes (bony outgrowths that form in the spine).

Laboratory tests: There are no specific laboratory tests for axSpA. However, blood tests can help exclude other conditions that can mimic the disease, such as rheumatoid arthritis or infections. HLA-B27 testing may also be useful as it is strongly associated with axSpA, although not all patients with axSpA are HLA-B27 positive.


AxSpA is a heterogeneous disease, and patients can present with different phenotypes that may require tailored treatment strategies. The following are the three main phenotypes of axSpA:

Radiographic axSpA (r-axSpA): This phenotype is characterized by radiographic evidence of sacroiliitis, which is visible on X-ray. Patients with r-axSpA tend to have more severe and progressive disease, with more frequent and severe spinal fusion.

Non-radiographic axSpA (nr-axSpA): This phenotype presents with clinical symptoms of axSpA, such as chronic back pain and stiffness, without radiographic evidence of sacroiliitis on X-ray. However, these patients may have positive MRI findings, such as bone marrow edema or inflammation of the sacroiliac joint, indicating early disease.

Peripheral spondyloarthritis: This phenotype involves inflammation of the peripheral joints, such as the knees, ankles, and wrists, in addition to axial symptoms. Peripheral spondyloarthritis can occur in isolation or in combination with axSpA.

There are various treatment options available that can help manage the disease.

Non-Steroidal Anti-Inflammatory Drugs (NSAIDs) are commonly used as a first-line treatment for axSpA, as they help to relieve pain and inflammation. They work by blocking the production of prostaglandins, which are responsible for causing pain and inflammation. Examples of NSAIDs include ibuprofen, naproxen, and diclofenac. NSAIDs can be taken orally or topically, and are usually taken on an as-needed basis.

Disease-Modifying Anti-Rheumatic Drugs (DMARDs) are a group of medications that work to modify the underlying disease process of axSpA. Unlike NSAIDs, DMARDs are slow-acting and can take several weeks or months to take effect. They are typically used in combination with NSAIDs for maximum benefit. Examples of DMARDs used for axSpA include sulfasalazine and methotrexate.

Biologic therapy targets specific proteins involved in the inflammatory process, such as tumor necrosis factor (TNF) or interleukin-17 (IL-17). These medications are administered via injection or intravenous infusion and are reserved for patients who have not responded to NSAIDs and/or DMARDs. Examples of biologics used for axSpA include adalimumab, etanercept, infliximab, golimumab, certolizumab pegol, and secukinumab.

Janus Kinase (JAK) Inhibitors are a newer class of medications that work by blocking a group of enzymes called Janus kinases, which are involved in the inflammatory process. They are taken orally and have been shown to be effective in treating axSpA. Tofacitinib is an example of a JAK inhibitor that has been approved for the treatment of axSpA.

Physical Therapy and Exercise are important components of the overall treatment plan for axSpA. They can help to improve flexibility, strength, and range of motion, and can also help to reduce pain and stiffness. A physical therapist can develop an individualized exercise program that is safe and effective for each patient.