<p>Enthesitis-related arthritis: current perspectives</p>

Abstract

In this narrative review, we overview the recent literature on enthesitis-related arthritis (ERA). For the purpose of our review, we searched Scopus for recent articles on this subject from 2013 onward, including some classic older articles for perspective. ERA is a juvenile idiopathic arthritis (JIA) subtype more common in males, associated in a majority with human leucocyte antigen B27. Such children generally present with asymmetric oligoarthritis or polyarthritis, predominantly of lower limb joints, associated with enthesitis or sacroiliitis. While diagnosis remains clinical, ultrasound is being increasingly used to detect subclinical enthesitis and for guiding entheseal site injections. Spine MRI can help detect sacroiliitis, inflammatory spinal changes, and pelvic sites of enthesitis in such patients. The recent juvenile spondyloarthropathy disease activity index recognizes the key clinical features of ERA, viz enthesitis and inflammatory back pain, which other disease activity indices used in JIA did not include. Management includes NSAIDs with physical therapy. Conventional disease-modifying agents like sulfasalazine and methotrexate may be used to minimize duration of NSAID use and in those with high inflammatory burden. In patients refractory to these drugs, biologics such as antitumor necrosis factor alpha agents have proven useful, based on evidences from randomized controlled trials and retrospective registry analyses. Factors predicting a poorer outcome in such children include hip or ankle involvement or restricted spinal mobility. Considering that children with ERA have overall poorer long-term outcomes than other subtypes of JIA, there is a need to further optimize therapeutic strategies for such patients.

Enthesitis Related Arthritis in a Longitudinal Southeast Asian Registry: High Prevalence of HLA-B27, Different Sacroiliitis Risk Factors and Less Common Drug-Free Remission

“…NSAIDs remained the mainstay first line therapy for our ERA patients, similar to reports elsewhere [ 2 , 4 , 17 , 23 ]. The majority of ERA patients had SSZ (79%), as it is our practice to use SSZ in all HLA-B27-positive patients unless G6PD deficiency or intolerable adverse reaction occurred.…”

“…The majority of our ERA patients presented with oligoarthritis (90%) similar to other cohort observations [ 4 , 17 ]. However, hip was the most common joint involved both at diagnosis (44%) and later (60%), followed by knee (38% and 58%) and ankle (26% and 43%) joints compared with the American, Taiwanese, Chinese and Canadian cohorts where knee arthritis was the most common joint involved cumulatively (46%, 52%, 45%, 38%, respectively) [ 2 , 17 , 22 , 23 , 24 ]. Upper extremity joints were involved in less than 10% of our patients.…”

Hip involvement in children with enthesitis related arthritis (ERA) is associated with poor outcomes in adulthood

“…Median CRP was 2.31 (0.74-4.82) mg/dl and median ESR was 24.5 (14.7-40) mm/h. Two-thirds (60%) had functional disability (HAQ-DI ≥ 0.5) and median BASFI was 1.6 [1,2].…”

“…About 70-75% of these children are HLA B-27 positive. Over time, some of these children develop features of involvement of the spine in the form of low backache, clinical, and radiological sacroiliitis [2].…”

Patients with enthesitis related arthritis show similar monocyte function pattern as seen in adult axial spondyloarthropathy

“…Enthesitis related arthritis (ERA) category of juvenile idiopathic arthritis (JIA) is characterized by lower limb arthritis and enthesitis and is usually seen in boys older than 6 years (14). HLA-B27 is present in 60-80% of these children (15).…”