What is the management approach for reactive lymph nodes identified on pediatric abdominal ultrasound?

From the Guidelines

Reactive lymph nodes identified on pediatric abdominal ultrasound should be managed with a watchful waiting approach, as they are often a normal immune response to various stimuli. When these nodes are found incidentally and the child is otherwise asymptomatic, a follow-up ultrasound in 3-6 months is recommended to ensure stability or resolution, as suggested by the principles outlined in the management of abdominal conditions in children, such as suspected appendicitis 1. The key factors to consider in the management of reactive lymph nodes include:

• The size of the lymph nodes, with nodes greater than 1-1.5 cm in short axis potentially warranting further evaluation
• The presence of concerning symptoms such as persistent fever, weight loss, or night sweats
• The appearance of the lymph nodes on ultrasound, with reactive nodes typically being oval in shape, having a preserved fatty hilum, and normal vascularity
• The clinical context, including the likelihood of recent viral infections or other immune stimuli In the absence of concerning features, no medications or procedures are typically needed for isolated reactive lymphadenopathy, emphasizing the importance of avoiding unnecessary interventions while ensuring appropriate follow-up. Further evaluation, including laboratory testing, additional imaging, or referral to pediatric hematology/oncology, may be warranted if the lymph nodes are accompanied by concerning symptoms or if their appearance is suspicious for a pathologic process. The approach to managing reactive lymph nodes in pediatric abdominal ultrasound prioritizes minimizing unnecessary interventions while maintaining vigilance for potentially concerning findings, aligning with the principles of managing suspected appendicitis and other abdominal conditions in children, where the level of clinical risk and the clinical scenario guide the need for imaging and the optimal imaging modality 1.

From the Research

Management Approach for Reactive Lymph Nodes

The management approach for reactive lymph nodes identified on pediatric abdominal ultrasound involves a combination of clinical evaluation, imaging characteristics, and potentially, fine-needle aspiration biopsy.

• The use of point-of-care ultrasound in the pediatric emergency department can facilitate the diagnosis of lymph node swelling and help differentiate between reactive, infectious, and malignant processes 2.
• Ultrasound elastography can also be used to evaluate lymph nodes and detect early malignant infiltration, providing a non-invasive method for assessing lymph node stiffness and homogeneity 3.
• In children, mesenteric lymph nodes with a short-axis diameter of >5-10 mm are commonly found on abdominal CT examination and should be considered a non-specific finding, with a short-axis diameter of 8 mm potentially defining the upper limit of normal mesenteric lymph node size 4.
• The evaluation of abdominal lymph nodes by ultrasound can provide information on the number, localization, dimensions, shape, and architecture of the nodes, which can be helpful in differentiating between benign and malignant involvement 5.
• In a normal pediatric population, abdominal lymph nodes can be present and are often larger and more numerous in the mesenteric region than in the para-aortic region 6.

Key Considerations

• The shape, size, internal echotexture, borders, vascularity, and pattern of perinodal soft tissue should be assessed when evaluating lymph node pathology 2.
• The use of high-frequency probes and graded compression can provide high-resolution images of abdominal lymph nodes in children 6.
• Fine-needle aspiration biopsy may be necessary to establish a diagnosis in cases where there is a considerable overlap between benign and malignant characteristics 5.