Enthesitis in an inception cohort of enthesitis‐related arthritis

Abstract

Objective. To describe an enthesitis-related arthritis (ERA) inception cohort and determine which entheses and joints are most commonly affected. Methods. We reviewed a retrospective inception cohort study of children with ERA who were diagnosed and treated at The Children's Hospital of Philadelphia between November 2007 and December 2009. Results. During the study period, there were 32 newly diagnosed ERA patients. Fifty-nine percent were male, and the median age at the date of initial evaluation was 12.5 years (interquartile range [IQR] 10.2-14.3 years). The median number of tender entheses at presentation was 2 (IQR 0 -5), and 21 subjects (66%) had at least 1 tender enthesis. The most prevalent tender entheses were the patellar ligament insertion at the inferior pole of the patella, the plantar fascial insertion at the calcaneus, the Achilles tendon insertion at the calcaneus, and the plantar fascial insertion at the metatarsal heads. Enthesitis was most often symmetric. The median number of active joints was 2 (IQR 0 -4). The most commonly affected joints were the sacroiliacs, knees, and ankles. Sacroiliitis, which was defined clinically, was most often symmetric, while peripheral arthritis was most frequently asymmetric. The odds of having active enthesitis at 6 months increased significantly with each additional tender enthesis at the initial evaluation. Conclusion. Among pediatric patients with ERA, lower extremity enthesitis is prevalent at the time of diagnosis and is likely to persist 6 months later. Future studies should address standardization of the enthesitis examination, the pattern of enthesitis over time, enthesitis response to therapy, and the impact of enthesitis on quality of life.

Enthesitis-related arthritis

“…Positive and negative predictive values of clinical examination as compared to ultrasound as the gold standard for detecting enthesitis are 0.55 and 0.73, respectively [15]. Enthesitis may be detectable at one site during 47 % of visits and at three sites during 18 % of visits to the clinic in patients with ERA [16]. Use of pressure of 40 lb/in 2 with a dolorimeter helps standardize the pressure applied, reducing intra-and interobserver variability.…”

“…Hence, not all tender points are entheseal sites. Enthesitis is a more common presenting symptom in juvenile as compared to adult SpA and has been linked with ongoing disease activity 6 months after diagnosis [8,16]. Of note, the American College of Rheumatology (ACR) pediatric response criteria (Table 1) do not take into consideration presence or absence of enthesitis, hence limiting their use in patients with ERA [17].…”

Juvenile Spondyloarthritis

“…HLA-B*27:05 is the most common subtype seen in JSpA (9). While HLA-B27 positivity is reported in more than 95% of adults with AS, recent JSpA studies demonstrate a lower prevalence of approximately 50% (10,11). Several theories regarding the role of HLA-B27 in directly or indirectly stimulating an inflammatory response include: 1) HLA-B27 misfolding, 2) HLA-B27 binding of arthrogenic peptides, and 3) HLA-B27 dimerization (12).…”

“…Enthesitis is inflammation at the attachment of tendons, ligaments, and joint capsule to bone that results in pain, swelling and tenderness. The most commonly tender entheses are the insertions of the patellar ligament at the inferior patella, plantar fascia at the calcaneus, and the Achilles tendon (10). Recent work suggests that children with JSpA have altered pain thresholds in comparison to healthy children and that tenderness at the entheses overestimates objective signs of inflammation visualized with imaging modalities such as ultrasound (20).…”

Discordant inflammatory changes in the apophyseal and sacroiliac joints: serial observations in enthesitis-related arthritis

“…1 The most commonly affected joints at diagnosis are the sacroiliac joints (SIJs), knees, ankles and hips. 2 Axial inflammation is a hallmark of ERA and up to 35-48% of children with ERA have clinical or radiographic evidence of sacroiliitis. [3][4][5][6] A subset of children with sacroiliitis will progress to spondylitis as adults, which is characterized by back pain, stiffness and eventual fusion of the vertebra.…”