Ultrasound in pediatric patients with clinically first joint pain

Abstract

© JOURNAL OF THE MEDICAL ASSOCIATION OF Thailand | 2019 Background: Joint pain in children is a presentation of important differential diagnoses including juvenile idiopathic arthritis (JIA) and septic arthritis, which can cause permanent joint destruction. In children, un-cooperativeness and thick subcutaneous fat may limit evaluation of joint inflammation. Objective: To evaluate association of physical examination and ultrasound findings in pediatric patients with clinically first joint pain and association of ultrasound findings and final diagnosis. Materials and Methods: Children (16 years old or younger) with clinically first joint pain but equivocal clinical diagnosis were eligible if they were sent for ultrasound of the joint. Images were reviewed by two investigators using consensus agreement. The ultrasound findings were assessed for joint effusion, synovial thickening, synovial hyperemia, peri-articular soft tissue swelling, and bone erosion. Clinical examination and final diagnosis were reviewed from medical record. Patients with incomplete clinical data and those with underlying disease of hemophilia were excluded. Results: The retrospective study consisted of 50 patients (87 joints). Most common ultrasound abnormality was joint effusion in 19 of 87 (21.8%) joints. There was significant association between ultrasound findings and physical examination (p<0.001). Ultrasound detected abnormal findings in two of 30 joints, which were not detected on physical examination. Provisional diagnoses were septic arthritis (44%) and acute inflammatory arthritis (26%). Only eight patients (16%) were sent under clinical suspicion of JIA. Thirty-three patients had diagnoses changed after ultrasound. At the final diagnosis, only one patient (2%) was diagnosed as septic arthritis and 17 patients (34%) as JIA. Most common diagnosis associated with synovial thickening and synovial hyperemia was JIA [in 10 of 15 (66.7%) and six of eight (75%) of cases, respectively]. Negative ultrasound finding was found in cases clinically suspected of neoplasm. Conclusion: Ultrasound in pediatric patients with clinically first joint pain showed significant correlation with physical examination. In some cases, ultrasound can contribute positive findings even when physical sign is not present. Synovial thickening, synovial hyperemia, peri-articular soft tissue swelling, and negative finding by ultrasound showed significant correlation with final diagnoses. The findings of synovial thickening and synovial hyperemia frequently associated with JIA.