Musculoskeletal ultrasound findings in adult-onset Still's disease: A case series.

Adult-onset Still's disease (AOSD) is a rare systemic inflammatory disorder of unknown etiology characterized by high spiking fever, salmon-like skin rash, arthritis, and elevated serum ferritin levels. Early detection of AOSD is remarkably difficult because of the lack of serologic biomarkers, nonspecific presentation, and rarity of the disease. Although arthralgia and arthritis are the most frequent symptoms and are correlated with health-related quality of life in patients with AOSD, the inflammatory changes associated with these symptoms have not been elucidated. We performed musculoskeletal ultrasound (MSKUS) in 11 patients between January 1, 2008 and July 31, 2023, seven of whom had abnormalities. MSKUS findings of those cases suggested that some patients with AOSD could present with tenosynovitis, tendonitis/peritendonitis, bursitis, and enthesitis along with synovitis. This case series demonstrate the diversity of inflammatory articular manifestations of AOSD identified by MSKUS.