The presence of an intra-articular knee effusion requires an extensive differential diagnosis and a systematic diagnostic approach. Pediatric knee effusions occur most commonly as acute hemarthroses after traumatic injury. However, the knee joint is susceptible to effusions secondary to a wide variety of atraumatic causes. Special attention is required in the atraumatic effusion to distinguish features of infectious, postinfectious, rheumatologic, hematologic, vasculitic, and malignant disease. This review discusses the various etiologies of both traumatic and atraumatic pediatric knee effusions highlighting the historical, physical examination, and laboratory characteristics to aid the emergency provider in diagnosis and initial management.
*Fellow (Mathison), Associate Chief (Teach), Division of Emergency Medicine, Children's National Medical Center; and †Instructor in Pediatrics (Mathison), Professor of Pediatrics and Emergency Medicine (Teach), George Washington School of Medicine and Health Sciences, Washington, DC.
Reprints: David J. Mathison, MD, Division of Emergency Medicine, Children's National Medical Center, 111 Michigan Ave NW, Washington, DC 20010 (e-mail: firstname.lastname@example.org).
Unless otherwise noted below, each faculty's spouse/life partner (if any) has nothing to disclose.
The authors have disclosed that they have no significant relationship with or financial interests in any commercial companies that pertain to this educational activity.
All staff in a position to control the content of this CME activity have disclosed that they have no financial relationships with, or financial interests in, any commercial companies pertaining to this educational activity.
Lippincott CME Institute has identified and resolved all faculty conflicts of interest regarding this educational activity.