06/12/2024
https://www.facebook.com/share/p/1EvR1q5Pbo/?mibextid=WC7FNe
Just published in JAMA 🔥
Axial Spondyloarthritis : A Review
📘 https://jamanetwork.com/journals/jama/article-abstract/2827540
👉 Axial spondyloarthritis is a multisystem inflammatory disease characterized by inflammation of the axial skeleton, including the sacroiliac joints and the spine. Axial spondyloarthritis can also affect the peripheral joints and organs such as the skin, eyes, and gastrointestinal tract (peripheral arthritis, enthesitis, or uveitis in about 20% of cases, https://pubmed.ncbi.nlm.nih.gov/19147614/). Axial spondyloarthritis encompasses radiographic (known as ankylosing spondylitis) as well as nonradiographic disease (https://pubmed.ncbi.nlm.nih.gov/19297345/).
👉 It affects approximately 1% of adults in the US and is associated with impaired physical function and reduced quality of life (https://pubmed.ncbi.nlm.nih.gov/23841117/).
👉 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 is the most common symptom of axial spondyloarthritis and affects more than 80% of patients.
👉 The pathogenesis of axial spondyloarthritis may involve genetic predisposition (https://pubmed.ncbi.nlm.nih.gov/25861975/), gut microbial dysbiosis (https://pubmed.ncbi.nlm.nih.gov/26002022/), and entheseal trauma (https://pubmed.ncbi.nlm.nih.gov/30266977/), with immune cell infiltration of the sacroiliac joints and entheseal insertion areas in the spine.
👉 There are currently no diagnostic criteria for axial spondyloarthritis. The diagnosis, often delayed 6 to 8 years after symptom onset (https://pubmed.ncbi.nlm.nih.gov/33428758/), is based on history (ie, inflammatory back pain, sensitivity, 74%-81%; specificity, 25%-44%), https://pubmed.ncbi.nlm.nih.gov/30713715/), laboratory findings (human leukocyte antigen B27–positive, sensitivity, 50%; specificity, 90%, https://pubmed.ncbi.nlm.nih.gov/38125058/) and elevated C-reactive protein level (sensitivity, 35%; specificity, 91%, https://acrabstracts.org/abstract/systematic-literature-review-and-meta-analysis-informing-the-development-of-2023-spondyloarthritis-research-and-treatment-network-spartan-referral-recommendations-for-axial-spondyloarthritis/), and imaging findings consisting of sacroiliitis on plain radiography (sensitivity, 66%; specificity, 68%, https://pubmed.ncbi.nlm.nih.gov/34049855/) or magnetic resonance imaging (sensitivity, 78%; specificity, 88%, https://pubmed.ncbi.nlm.nih.gov/31797168/).
👉 First-line treatments are exercise therapy and nonsteroidal anti-inflammatory drugs (NSAIDs). Exercise therapy is important for muscle strengthening, to maintain good range of motion and appropriate posture. A multicenter randomized clinical trial of 100 patients with axial spondyloarthritis reported that supervised high-intensity exercise led to improvements in disease activity scores (https://pubmed.ncbi.nlm.nih.gov/30745314/).
👉 As less than 25% of patients achieve complete symptom control with NSAIDs, approximately 75% of patients require biologic drugs (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.
📷 Figure (https://jamanetwork.com/journals/jama/article-abstract/2827540): Multiple mechanisms play a role, including HLA-B27, gut microbiome, and mechanical stress. The interaction between dendritic cells and CD8+ T cells, as well as the activation of CD4+ T cells, promote an inflammatory cascade characterized by the production of several cytokines including interleukin (IL) 23, IL-22, IL-17, and tumor necrosis factor. With chronic inflammation, new bone formation will occur. This is thought to be due to mesenchymal cell proliferation leading to osteoblast differentiation, mediated by multiple signaling pathways including Wnt, bone morphogenetic protein, and hedgehog.
