Importance of sonographic detection of enlarged abdominal lymph nodes in children.

OBJECTIVE: Abdominal lymph nodes are frequently visualized by sonography in the pediatric population. The term "mesenteric lymphadenitis" is frequently used in the radiologic literature to describe this finding, whereas in the pediatric literature, this term is reserved for specific inflammation of the lymph nodes. The purpose of this study was to compare by sonography the incidence of appearance of enlarged abdominal lymph nodes (EALNs) in healthy children compared with that in children with abdominal pain of various causes.
METHODS: In 200 patients referred for abdominal sonography for various indications, the presence of EALNs, their location, and size were registered. The patients were divided into 3 groups: those with abdominal pain due to an acute abdominal condition (group 1), those with abdominal pain without an acute abdominal condition (group 2), and asymptomatic patients (group 3).
RESULTS: Enlarged abdominal lymph nodes greater than 5 mm were detected in 83.3% of group 1 patients, 73.8% of group 2 patients, and 64% of group 3 patients. A significant statistical difference was found between patients with abdominal pain and asymptomatic children only for lymph nodes of 10 mm and larger (P = .0117). No statistically significant difference was seen in the presence of lymph node clusters between the patients with abdominal pain and asymptomatic children. There was a tendency of increased EALN occurrence with age, peaking at 10 years, with a decrease later.
CONCLUSIONS: Enlarged abdominal lymph nodes are frequently encountered in asymptomatic children and should not always be considered abnormal. Enlarged abdominal lymph nodes exceeding 10 mm in their shortest axis in children with abdominal pain may represent mesenteric lymphadenitis of various causes.