Differentiation of psoas muscle abscess from septic arthritis of the hip in children

A 20-year review was conducted of children presenting with psoas abscess at two major pediatric hospitals. Eleven children with psoas abscesses were i dentified. The extreme variability in the clinical presentation of this con dition is shown. Psoas abscess was most difficult to differentiate from sep tic arthritis of the hip in pediatric patients. This study also shows the o ften circuitous investigative route traversed before arriving at the diagno sis of psoas abscess. Atypical features, such as femoral nerve neurapraxia or bladder irritability in association with hip pain, should alert the clin ician to consider psoas abscess. Based on this study, a diagnostic algorith m to differentiate between psoas abscess and septic hip was formulated.