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Magnetic Resonance Imaging Identifies Features in Clinically Unaffected Knees Predicting Extension of Arthritis in Children with Monoarthritis
JANET M. GARDNER-MEDWIN, ORLA G. KILLEEN, CLIVE A.J. RYDER, KAREN BRADSHAW, and KARL JOHNSON ABSTRACT. Objective. A proportion of children with oligoarthritis have an aggressive disease course. Identifying these children at presentation would help guide prognosis and management. We examined if magnetic resonance imaging (MRI) of clinically unaffected joints is more sensitive than clinical assessment in identifying those at risk of developing arthritis in more than one joint. Methods. Ten children were recruited; they had a mean age of 9.4 (range 5.2–14.2) years at presentation of a monoarthritis. MRI of a clinically unaffected knee was performed within 4 months of presentation, and was reported by 2 pediatric radiologists blinded to the clinical findings. All MR examinations included post-gadolinium sequences. Joints with clinically apparent arthritis were recorded regularly over a median of 37.0 (range 6.6–47.0) months by a median of 6.0 (range 2–8) pediatric rheumatologists blinded to the MR result. Results. Four children developed arthritis in other joints over a median of 3.9 (range 3–6) months after the MRI scan; all had abnormal MRI scans at presentation. Three of these developed clinical features in the previously normal knee 4–11 months after MRI identified small joint effusions, synovial hypertrophy, and lymph node enhancement. One child developed a polyarthritis, but never developed clinical features in the imaged knee over 3.8 years of followup. Four other children had a persistent monoarthropathy with a median followup of 29.5 (range 6.6–42.0) months. All 4 had normal MRI. Two children had reactive arthritis. Conclusion. MRI distinguished between patients with a persistent monoarthritis and those who developed further clinical arthritis up to 1 year later. The results suggest a widespread inflammatory process may exist in children whose arthritis extends, and this has implications for our understanding of disease and the design and timing of therapeutic interventions. (First Release Sept 15 2006; J Rheumatol 2006;33:2337-43) Key Indexing Terms:
JUVENILE IDIOPATHIC ARTHRITIS From the Department of Child Health, Royal Hospital for Sick Children, Yorkhill; and Division of Developmental Medicine, University of Glasgow, Glasgow, and Birmingham Children's Hospital, Birmingham, United Kingdom. J.M. Gardner-Medwin, MRCP, PhD, Senior Lecturer in Paediatric Rheumatology; O.G. Killeen, MRCPCH, Clinical Research Fellow, Division of Developmental Medicine, University of Glasgow and Birmingham Children's Hospital; C.A.J. Ryder, MRCP, Consultant Paediatric Rheumatologist; K. Bradshaw, MRCP, FRCR, Consultant Radiologist; K. Johnson, MRCP, FRCR, Consultant Paediatric Radiologist, Department of Child Health, Royal Hospital for Sick Children. Address reprint requests to Dr. J. Gardner-Medwin, Department of Child Health, Royal Hospital for Sick Children, Yorkhill, Glasgow, G3 8SJ, UK. E-mail: jgm4w@clinmed.gla.ac.uk Accepted for publication June 7, 2006.
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