CPD Shorts: Ultrasound features of paediatric mesenteric adenitis

As part of the Ultrasound Advisory Group series of short learning activities for sonographers to help with their CPD, this article aims to highlight the role of ultrasound in the diagnosis and management of paediatric mesenteric adenitis. 

Six Key Points

1. Mesenteric adenitis is a common clinical finding in the paediatric population. It is characterised by inflammation of the mesenteric lymph nodes, which are located in the abdomen around the small intestine.
2. Mesenteric adenitis is often mistaken for acute appendicitis, as both conditions can present with similar symptoms, such as right lower quadrant pain, fever, and nausea.
3. Ultrasound Features: Ultrasound is the imaging modality of choice for suspected mesenteric adenitis. The typical ultrasound findings of mesenteric adenitis include:
   • Enlarged lymph nodes. The lymph nodes are typically 5mm or more in short-axis diameter.
   • Clustered lymph nodes. The lymph nodes are often clustered together in the right lower quadrant.
   • Hypervascular lymph nodes. The lymph nodes may show increased blood flow on Doppler imaging.
   • Normal appendix. It is important to visualize the appendix to rule out acute appendicitis.
4. Other Findings: In addition to enlarged lymph nodes, ultrasound may also show other findings in patients with mesenteric adenitis, such as:
   • Thickened bowel wall. The bowel wall may be thickened, particularly in the ileocecal region.
   • Free fluid in the abdomen. Free fluid may be present in the abdomen, particularly in more severe cases.
5. Differential Diagnosis: It is important to visualize the appendix to rule out acute appendicitis. The differential diagnosis of mesenteric adenitis includes:
   • Acute appendicitis
   • Intussusception
   • Meckel's diverticulitis
   • Crohn's disease
   • Typhlitis
6. Management:The management of mesenteric adenitis is supportive. Patients are usually treated with pain medication and antibiotics. The condition typically resolves within a few days.

Reflection Prompts

• How often do you see mesenteric adenitis in your practice?
• What are the challenges of diagnosing mesenteric adenitis?
• How do you use ultrasound to diagnose mesenteric adenitis?
• What are the other imaging findings that you may see in patients with mesenteric adenitis?
• How do you manage patients with mesenteric adenitis?

Further Reading

• Quigley, A. Stafrace, S. (2013) Ultrasound assessment of acute appendicitis in paediatric patients: methodology and pictorial overview of findings seen. Insights Imaging. 4 (6): 741-51. doi:10.1007/s13244-013-0275-3.
• Radiopaedia (2022) Mesenteric adenitis. https://radiopaedia.org/articles/mesenteric-adenitis 
• Zu, D. Feng, L. Zhang, L. Ma, S. Zhu, Y.  (2019) Evaluation of Mesenteric Lymph Nodes in a Pediatric Population with Mesenteric Lymphadenitis Using Superb Microvascular Imaging. Medical Science Monitor. 25: 5336-5342. doi:10.12659/MSM.914903.