Ultrasonographic evaluation of the free intraperitoneal fluid in asymptomatic children.

Background: Free intraperitoneal fluid can be an important sign in an abdominal inflammatory process or abdominal trauma. It is often present in children with abdominal pain, but it is a nonspecific finding. A minimal amount of free intraperitoneal fluid is considered normal.

Objective: The purpose of this study was to evaluate the incidence, location and volume of free fluid in the abdomen and pelvis in a population of asymptomatic children.

Materials And Methods: In this prospective study, we performed clinically indicated abdominal and pelvic sonography, using high-resolution transducers, in 200 asymptomatic children: 104 (52%) girls, 96 (48%) boys; ages 6 days-15 years (mean 3 years 8 months). US studies were performed and prospectively evaluated by two experienced pediatric radiologists. Patients with any condition that could result in the accumulation of free intraperitoneal fluid as well as postpubertal girls were excluded from the study.

Results: Free intraperitoneal fluid was seen in 12 children (6%), only in the pelvis. Fluid volume never exceeded 1 ml.

Conclusion: Our study suggests that 1 ml or less of free intraperitoneal fluid detected in the pelvis is probably insignificant.