Diagnosis of axial spondyloarthritis includes ankylosing spondylitis and non-radiographic axial spondylitis arthritis, based on the presence of sacroiliitis on MRI or plain radiography and at least one spondyloarthritis feature or HLA -B 27 positivity, and at least two spondyloarthritis features.
Usually occurs in the second or third decade of life, with less than 5% of patients diagnosed when older than 45 years of age.
Axial spondyloarthritis is an immune-mediated inflammatory condition involving the sacroiliac joints, spine, and peripheral joints.
It affects approximately 1% of adults in the US and is associated with impaired physical function and reduced quality of life.
It refers to an inflammatory chronic back pain characterized by gradual onset starting before age 45 years, prolonged morning stiffness, improvement with exercise, and lack of improvement with rest.
These are the most common symptoms of axial spondyloarthritis and affects more than 80% of patients.
Typically appears in those younger than 45 years and has a peak age you don’t say between 20 and 30 years.
The pain is inflammatory as suggested by: improvement with exercise, pain at night, insidious onset of pain, aged onset younger than 40 years, and no improvement with rest.
Patients with axial spondyloarthritis may also have inflammatory arthritis in large peripheral joints, most commonly knees.
Patients with axial spondyloarthritis may also have an oligoarticular, asymmetric inflammation at tendon insertions, inflammatory eye disease (uveitis); psoriasis; and inflammatory bowel disease.
The etiology of axial spondyloarthritis may involve genetic predisposition, gut microbial dysbiosis, and entheseal trauma, with immune cell infiltration of the sacroiliac joints and entheseal insertion areas in the spine.
No diagnostic criteria for axial spondyloarthritis, and the diagnosis is often delayed 6 to 8 years after symptom onset.
Diagnosis is based on history of inflammatory back pain, human leukocyte antigen B27–positive [sensitivity, 50%; specificity, 90%] and elevated C-reactive protein level [sensitivity, 35%; specificity, 91%]), and imaging findings consisting of sacroiliitis on plain radiography (sensitivity, 66%; specificity, 68%) or magnetic resonance imaging (sensitivity, 78%; specificity, 88%).
Management:
First-line treatments are physical therapy and nonsteroidal anti-inflammatory drugs (NSAIDs).
Fewer than 25% of patients achieve complete symptom control with NSAIDs.
Approximately 75% of patients require biologic drugs such as tumor necrosis factor inhibitors [anti-TNF agents], interleukin 17 inhibitors [anti–IL-17 agents]) or targeted synthetic disease-modifying antirheumatic agents (Janus kinase [JAK] inhibitors) to reduce symptoms, prevent structural damage, and improve quality of life.
Anti-TNF agents significantly improved ASAS20 score measuring pain, function, and inflammation in 58% to 64% of patients compared with 19% to 38% for placebo.
Similar outcomes were attained with anti–IL-17 agents (48%-61%, vs 18%-29% with placebo) and JAK inhibitors (52%-56%, vs 26%-29% with placebo).
Anti-TNF agents, anti–IL-17 agents, and JAK inhibitors have been associated with reduced radiographic progression of axial spondyloarthritis.
Axial spondyloarthritis predominantly affects the sacroiliac joints and spine but is also associated with extraskeletal manifestations such as uveitis, psoriasis, and inflammatory bowel disease.
Chronic back pain and stiffness can occur over time leading to new bone formation, structural damage, and ultimately fusion of the sacroiliac joints in the spine in some patients, known as bamboo spine.
If at least four of the five criteria are identified, it has a sensitivity of 79.6% and a specificity of 72.4% in diagnosing inflammatory back pain.
In a patient with at least three months of inflammatory back pain, plain x-rays may show sacroiliitis with a sensitivity of 48%.
An under recognized cause of chronic low back pain is axial spondyloarthritis, an inflammatory rheumatic disease that predominately involves spine and sacroiliac joints.
T-weighted MRI of the pelvis or symptomatic spinal area can show sacroiliitis or spondylitis with the sensitivity of 85%.
In axial spondyloarthritis the disease is predominantly of the axial skeleton, but peripheral joints, and entheses, and extra articular organs such as the skin, eyes, and intestines are also frequently affected.
Nonsteroidal anti-inflammatory drugs are the mainstay of treatment.
Other biologic agents such as antitumor necrosis factor alpha may be employed.
Sulfasalazine is commonly utilized, especially for patients with peripheral arthritis, although its role in management has not been clinically demonstrated.