From the Guidelines
The presence of visible lymph nodes in the right lower quadrant on ultrasound in a 14-year-old male with abdominal pain and no visualization of the appendix is concerning for possible appendicitis or another inflammatory process, and warrants further evaluation. The ultrasound findings are significant because visible lymph nodes in this area are often enlarged due to inflammation or infection, which can be associated with appendicitis 1. Non-visualization of the appendix itself does not rule out appendicitis, as an inflamed appendix can sometimes be obscured by bowel gas or positioned in a location difficult to image.
Key Considerations
- The definition of an equivocal or nondiagnostic US for acute appendicitis varies widely in the literature, but careful definition of this category has major implications on imaging utilization 1.
- Some consider nonvisualization of the appendix as an equivocal result, however, in several retrospective studies, an appendiceal US in which the appendix is not visualized and no inflammatory findings are present in the RLQ has high negative predictive value 1.
- Further imaging is unlikely to be contributory unless there is discordance between the clinical picture and the negative US result, but can be beneficial after equivocal US examinations in which the appendix is either visualized or not visualized, and there are findings that could reflect appendicitis 1.
Recommendations
- The patient should be monitored for worsening pain, fever, vomiting, or other signs of progressing inflammation, as prompt treatment is important if appendicitis is confirmed.
- Further evaluation, potentially including additional imaging like a CT scan, continued clinical monitoring, or surgical consultation, should be considered depending on the severity of symptoms, physical exam findings, and laboratory results 1.
- Repeat clinical assessment can also be beneficial in these cases, which can obviate further imaging at the expense of delay in diagnosis and the risk associated with extending the hospital visit 1.
From the Research
Significance of Visible Lymph Nodes
- The presence of visible lymph nodes in the right lower quadrant on ultrasound in a 14-year-old male with abdominal pain and no visualization of the appendix may indicate an increased likelihood of appendicitis, as suggested by studies 2, 3.
- A study published in 2013 found that the presence of prominent lymph nodes, along with other secondary inflammatory changes, increased the odds ratio of appendicitis 2.
- Another study published in 2019 found that the presence of inflammatory changes in the right lower quadrant, including lymph nodes, was a significant predictor of appendicitis in patients with a non-visualized appendix 3.
Diagnostic Considerations
- The diagnosis of appendicitis can be challenging, especially when the appendix is not visualized on ultrasound, and the presence of lymph nodes should be considered in conjunction with other clinical and laboratory findings 3, 4.
- A case report published in 2019 highlighted the importance of considering atypical presentations of appendicitis, including subhepatic appendicitis, which may present with elevated lipase levels and prominent lymph nodes 4.
- Ultrasound is a useful diagnostic tool for evaluating children with acute right lower quadrant pain, and findings should be interpreted in the context of clinical judgment and other diagnostic tests 5, 6.
Ultrasound Findings
- Ultrasound findings, including lymph nodes, should be considered in the context of other secondary inflammatory changes, such as free fluid, phlegmon, and pericecal inflammatory fat changes, which can increase the specificity and sensitivity of the diagnosis of appendicitis 2.
- The presence of lymph nodes, along with other ultrasound findings, can help guide further diagnostic testing and management, including the potential need for surgical intervention 3, 6.