Background Spondyloarthritis (SpA), including ankylosing spondylitis (AS), psoriatic arthritis (PsA), reactive arthritis (ReA), enteropathic arthritis, undifferentiated spondyloarthritis (uSpA), and synovitis-acne-pustulosis-hyperostosis-osteitis (SAPHO) syndrome, often involves the entheses. The differences between early-onset and late-onset SpA are poorly understood.
Objectives To evaluate comparatively clinical characteristics, including positron emission tomography/computed tomography (PET/CT) using 18F-fluorodeoxyglucose (FDG) findings, of patients with between both early-onset and late-onset SpA in our hospital.
Methods We detected SpA group that developed in less than 45 years old as early-onset SpA (EOSpA), and in more than 65 years old as late-onset SpA (LOSpA). The clinical symptoms, laboratory findings and the results of PET/CT scans of twenty patients with EOSpA and twenty LOSpA were comparatively examined.
Results LOSpA had fever, body weight loss and severe systemic symptoms. Three of LOSpA (3/20) developed PMR-like symptoms. LOSpA showed significantly higher inflammatory reaction than EOSpA. Images of PET/CT scans revealed widespread FDG accumulations at the entheses in LOSpA patients, in comparison with EOSpA. The maximum SUVs were statistically higher in LOSpA patients compared EOSpA patients at the entheses (P < 0.05). Furthermore, three of LOSpA (3/20) had peripheral edema in lower extremities, and it pathologically showed panniculitis. There were no significant differences in HLA typing between EOSpA and LOSpA.
Conclusions LOSpA revealed severe clinical symptoms, inflammatory reactions, and widespread and strong enthesitis and arthritis compared with EOSpA. It is important to differentiate SpA, RS3PE syndrome and PMR in cases with peripheral edema, myalgia and pantalgia. We must investigate further cases of LOSpA in order to elucidate its pathophysiology and mechanisms of development.
Disclosure of Interest None Declared