What is Normal

Normal Lymph node:

Size: Lymph Nodes in the head and neck are generally considered abnormal if they measure greater than 10 mm (1 cm) in the short axis. The exception is the submandibular region, where a short axis of up to 15 mm can be considered normal (8).

The axial short-axis diameter of lymph nodes is more clinically significant, whereas the length of the node in the long axis is less standardized and often less clinically significant. However, the lymph node should still be evaluated in all three planes for a comprehensive assessment. (8)

Shape: Normal lymph nodes are ovoid, or “kidney shaped.“ However, in the submandibular region a normal node can appear round rather than ovoid.

Echogenicity: Normal lymph nodes have a  cortex and medulla. The outer cortex is more hypoechoic due to lymphoid follicles, while the central medulla is more hyperechoic due to a dense network of lymphatic cords and a central sharp linear hyperechoic fatty hilum containing blood vessels.

Surrounding tissue: In a normal or reactive lymph node, the surrounding tissue will not typically demonstrate anatomical or echogenic changes.

Vascularity: in a normal node, the central hilum is vascular on color Doppler.

 

Figure 4. Normal Lymph node with color Doppler. 

 

 

What am I looking at?

 

Lymph nodes are solitary ovoid structures composed of lymphoid tissue and are distributed along the lymphatic vessels.

Figure 2. Lymph node- illustration. Image Source: Dr. Giulia Pula 2024.

 

Each node is divided internally into cortex and medulla and encased by a capsule. Artery and vein enter and exit the lymph node at the hilum.

 

On ultrasound, the skin and subcutaneous tissue are the most superficial layers, with muscle groups just beneath. Depending on the location of the lymph node, you may also see surrounding structures such as the carotid artery, internal jugular vein, trachea, or adjacent glands (e.g., thyroid, submandibular). The lymph nodes themselves are visualized within the soft tissue between these landmarks. Vessels will appear as anechoic structures, tubular and elongated in the long axis or round and circular in the short axis, while glands demonstrate a more homogeneous, finely echogenic texture compared to surrounding muscle.

Figure 3: Cervical layers and normal lymph node on POCUS 

Technique

1. Place patient comfortably supine  
2. Position neck to best expose the swelling*    
3. Apply lots of gel for comfort if the area is tender (7) 
4. Consider pre-procedural analgesia 
5. Using the linear transducer, scan the area of interest in the longitudinal plane  
6. Scan the area of interest in the transverse plane. 
7. Assess the size, shape, echogenicity, borders, and vascularity of any lymph nodes. 
8. Apply color doppler to assess vascular flow to the area 
9. Document and describe characteristics of the mass. 
10. Describe any adjacent tissue findings 

*Usually this requires turning the head away from the swelling and in extension. This might be achieved by placing the patient in a semi recumbent position or in a caregiver’s lap, which might offer some gentle holding as well as comfort

 

Figure 1. Probe positon

 

 

 

When examining any neck swelling or mass using ultrasound, it’s crucial to observe and comment on the following characteristics:

Margins

o Are the margins smooth?

o Is there any definable capsule?

 

Shape/Size

o Describe the mass in three dimensions: Ovoid? Round? Irregular?

o The axial short-axis diameter and overall dimensions, if feasible

 

Echogenicity/internal structure

o Echotexture: Homogeneous? Heterogeneous? Echogenicity?

o Architecture: Shape? Lobulations?

o Is there a central hilum?

o Unique features: Ducts? Calcifications? Foreign body? Shadowing or other artifacts within?

 

Surrounding tissue

o Tissue thickening, edema, cobblestoning or echogenic fat?

o Relationship to other structures such as skin, subcutaneous fat, muscle, bone, glands: adjacent? embedded within? attached to? infiltrating?

o Artifacts in surrounding tissue: Posterior acoustic enhancement? Shadowing?

o Do the combinations of these indicate gas or fluid in the tissue?

 

Vascularity

o Is there increased flow? (Compared to an expected and/or similar structure)

o Location of vascularity: Radiating from a hilum? Peripheral? Adjacent vascular structures?

Indications

o Acute neck mass/swelling 

o Cervical lymphadenopathy 

o Suspected neck skin/soft tissue infection 

 

Equipment

o Ultrasound machine 

o High-Frequency Linear transducer (7-12 MHz) 

o Gel for acoustic interface 

Introduction

Neck mass is a common presenting complaint in the pediatric population with a broad differential diagnosis. Point of care ultrasound (PoCUS) provides a rapid, non-invasive, and real-time evaluation of these masses. Indications for bedside ultrasound assessment include palpable neck masses, cervical lymphadenopathy, and evaluation of suspected neck infections or malignancies. 

Common causes of neck swelling in children include enlarged lymph nodes, most often due to inflammatory or reactive responses, infections, or – less commonly – malignancies. Congenital developmental masses, benign neoplastic lesions, and salivary gland infections also contribute to the range of potential causes. Malignancies can also be a cause of neck swelling and are important to consider in the differential diagnosis although rare. 

In the evaluation of a neck mass, a comprehensive approach is essential. This involves gathering a detailed medical history, conducting a thorough physical examination, and investigations including laboratory work and imaging studies when clinically indicated (1). Cervical lymphadenopathy ranks among the most common contributors to neck swelling in children. This module will specifically concentrate on the assessment of the diverse causes of lymph node swelling using PoCUS. 

 

Why Ultrasound?

Ultrasound (US) is considered the primary imaging modality of choice for evaluating inflammatory neck masses because of its widespread availability, excellent resolution, and lack of ionizing radiation (2,3). Ultrasonography can define the size, shape, and characteristics of the mass and any associated vascularity. Ultrasonography can also define the tissues surrounding the mass, providing more clues to the etiology. Further, US is safe, cost-effective, and available in real time. It is also readily available in most hospital settings. 

 

 

PoCUS imaging of neck masses compares favourably to formal radiological assessments. One study assessed PoCUS with radiology department ultrasonography (RaDUS), while another compared PoCUS with multiple radiological evaluations (RaDUS, CT, or both). Both studies involved pediatric patients aged 0 to 18 years presenting with neck swelling to the emergency department. POCUS trained pediatric emergency physicians concurred with radiology-based imaging diagnoses in 77% -78% of cases in two studies with. Corresponding kappa values were also comparable—0.69 (95% CI 0.44–0.94) and 0.71 (95% CI 0.60-0.83) respectively (4,5).  

These studies not only highlight the diagnostic accuracy of PoCUS but also shed light on its ability to identify a wide range of neck pathologies. The spectrum of diagnoses includes, but is not limited to, lymph node abnormalities (infections, inflammation, and malignancies), solid tumors, congenital cysts, parotitis, and others. These findings support PoCUS as a reliable, rapid, and non-invasive diagnostic tool in the pediatric emergency setting, offering a valuable complement to history, physical exam, and other imaging modalities.  

In addition, performing PoCUS was found to reduce emergency department length of stay i in children presenting with neck masses (5,6). 

 

 

 

Primary Author: Elad Machtey, MD

Secondary Author(s): Melissa Skaugset, MD, FRCPC

Reviewer(s): Mark Bromley, MD, FRCPC; Melanie Willimann, MD, FRCPC

 

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References

1. Guan L, Liu Z, Pan G, Zhang B, Wu Y, Gan T, Ouyang G. The global, regional, and national burden of appendicitis in 204 countries and territories, 1990–2019: a systematic analysis from the Global Burden of Disease Study 2019. BMC gastroenterology. 2023 Feb 22;23(1):44.
2. Wickramasinghe DP, Xavier C, Samarasekera DN. The worldwide epidemiology of acute appendicitis: an analysis of the global health data exchange dataset. World Journal of Surgery. 2021 Jul;45:1999-2008.
3. Hamill JK, Liley A, Hill AG. Historical aspects of appendicitis in children. ANZ journal of surgery. 2014 May;84(5):307-10.
4. Ferris M, Quan S, Kaplan BS, Molodecky N, Ball CG, Chernoff GW, Bhala N, Ghosh S, Dixon E, Ng S, Kaplan GG. The global incidence of appendicitis: a systematic review of population-based studies. Annals of surgery. 2017 Aug 1;266(2):237-41.
5. https://emergencycarebc.ca/clinical_resource/suspected-appendicitis-in-children/
6. Schneider C, Kharbanda A, Bachur R. Evaluating appendicitis scoring systems using a prospective pediatric cohort. Annals of emergency medicine. 2007 Jun 1;49(6):778-84.
7. Cundy TP, Gent R, Frauenfelder C, Lukic L, Linke RJ, Goh DW. Benchmarking the value of ultrasound for acute appendicitis in children. Journal of pediatric surgery. 2016 Dec 1;51(12):1939-43.
8. Lee SH, Yun SJ. Diagnostic performance of emergency physician-performed point-of-care ultrasonography for acute appendicitis: A meta-analysis. Am J Emerg Med. 2019;37(4):696-705. doi:10.1016/j.ajem.2018.07.025
9. Matthew Fields J, Davis J, Alsup C, et al. Accuracy of Point‐of‐care Ultrasonography for Diagnosing Acute Appendicitis: A Systematic Review and Meta‐analysis. Mark Courtney D, ed. Acad Emerg Med. 2017;24(9):1124-1136. doi:10.1111/acem.13212
10. Cho SU, Oh SK. Accuracy of ultrasound for the diagnosis of acute appendicitis in the emergency department: A systematic review. Medicine (Baltimore). 2023;102(13):e33397. doi:10.1097/MD.0000000000033397
11. Scheier E, Shapira Levy E, Fisher A. POCUS for pediatric appendicitis in the pediatric emergency department: An 8‐year retrospective review. J Clin Ultrasound. 2024;52(9):1355-1359. doi:10.1002/jcu.23813
12. Kasmire K, Davis J. Emergency Department Point‐of‐Care Ultrasonography Can Reduce Length of Stay in Pediatric Appendicitis: A Retrospective Review. J Ultrasound Med. 2021;40(12):2745-2750. doi:10.1002/jum.15675
13. Pogorelic Z, Rak S, Mrklic I, Juric I. Prospective validation of Alvarado score and Pediatric Appendicitis Score for the diagnosis of acute appendicitis in children. Pediatric emergency care. 2015 Mar 1;31(3):164-8.
14. Sağ S, Basar D, Yurdadoğan F, Pehlivan Y, Elemen L. Comparison of appendicitis scoring Systems in Childhood Appendicitis. Turkish Archives of Pediatrics. 2022 Sep;57(5):532.
15. Kharbanda AB, Vazquez-Benitez G, Ballard DW, Vinson DR, Chettipally UK, Kene MV, Dehmer SP, Bachur RG, Dayan PS, Kuppermann N, O’Connor PJ. Development and validation of a novel pediatric appendicitis risk calculator (pARC). Pediatrics. 2018 Apr 1;141(4).
16. Sivit CJ. Diagnosis of acute appendicitis in children: spectrum of sonographic findings. AJR. American journal of roentgenology. 1993 Jul;161(1):147-52.
17. Jeffrey Jr RB, Laing FC, Townsend RR. Acute appendicitis: sonographic criteria based on 250 cases. Radiology. 1988 May;167(2):327-9.
18. Goldin AB, Khanna P, Thapa M, McBroom JA, Garrison MM, Parisi MT. Revised ultrasound criteria for appendicitis in children improve diagnostic accuracy. Pediatric radiology. 2011 Aug;41:993-9.
19. Rioux M. Sonographic detection of the normal and abnormal appendix. AJR Am J Roentgenol. 1992;158(4):773-778. doi:10.2214/ajr.158.4.1546592
20. Quigley AJ, Stafrace S. Ultrasound assessment of acute appendicitis in paediatric patients: methodology and pictorial overview of findings seen. Insights Imaging. 2013;4(6):741-751. doi:10.1007/s13244-013-0275-3
21. Sivitz AB, Cohen SG, Tejani C. Evaluation of acute appendicitis by pediatric emergency physician sonography. Annals of emergency medicine. 2014 Oct 1;64(4):358-64.
22. Borbély Márton. Appendicitis ultrasound [Internet]. Wikimedia Commons; July 6, 2024. Available from: https://commons.wikimedia.org/wiki/File:Appendicitis_ultrasound.png.

Summary

• Ultrasound is the diagnostic method of choice in pediatrics for appendicitis, and POCUS can provide rapid, real-time assessment.
• The appendix position varies, making it challenging to locate, especially in retrocecal or pelvic positions.
• Begin with the point of maximal tenderness, then use anatomical identification and graded compression to improve visualization.
• If the appendix is found, scan in both short and long axes and apply color Doppler to assess vascularity and inflammation.
• Dilation of the appendix >6mm, along with secondary findings such as wall thickening, hypervascularity, free fluid, echogenic fat, lymphadenopathy, and the presence of an appendicolith are key findings confirming appendicitis.
• PoCUS for appendicitis should be used as a rule-in test, where a positive result supports the diagnosis—helping guide immediate management decisions, but a negative scan alone does not reliably rule it out.
  • With increased scanning experience and full visualization of the appendix from base to tip, the reliability of PoCUS as a rule-out tool may improve, but this requires a high level of proficiency.