Written by: Dr. Jaron Kurian

Edited by: Dr. Joann Hsu

The case:

7 y/o F with no PMH comes in today for evaluation of RLQ abdominal pain, associated with nausea and vomiting.

Exam significant for right lower quadrant tenderness.

Labs significant for WBC 19

Pediatric abdominal ultrasound

In general, you will be reaching for the linear probe rather than the curvilinear, but this will depend on the age/size/body habitus of the child.
The linear probe allows for greater resolution in near and far fields, but has limited depth and width. In contrast, the curvilinear probe has worse resolution in the far and lateral fields in comparison but allows for a larger/deeper image.
You can get away with the higher resolution linear probe in children oftentimes because there is much less depth to travel through in pediatric abdominal scans.

Bedside ultrasound showed:

Appendicitis

Acute inflammation of the vermiform appendix
Most common non-obstetric surgical emergency in pregnancy
Most common abdominal surgical emergency in patients < 50
Most common between 10-30 years, but no age is exempt
Most commonly caused by luminal obstruction by a fecalith 33% of patients have atypical presentation
Retrocecal appendix can cause flank or pelvic pain
Gravid uterus sometimes displaces appendix superiorly → RUQ pain

Technique:

Sonographer Dependent!!!!
Begin by placing the transducer in a transverse position and applying deep graded compression to displace the gas between transducer and bowel
Beginning at the hepatic flexure the bowel is traced down to the caecum.
The patient should point to the location of pain .
The external iliac artery and vein can provide a good landmark for finding the appendix because of the location and pulsatility - turn on color if you’re not sure if there are vessels.
Don’t forget to look in both transverse and longitudinal planes
Limiting Factors:
- Bowel gas and patient habitus are the biggest limiting factors to visualising the appendix.
- Up to 60% of appendices are retrocaecal and thus may be obscured.
- Not identifying an appendix does NOT exclude appendicitis.

What are you looking for:

A blind ending & tubular structure that is not undergoing peristalsis, noncompressible, and at least 6 cm or greater in diameter.
When you locate this, turn your probe to view the appendix in short axis and measure the anterior to posterior diameter
Echogenic inflammatory periappendiceal fat change - “hot fat'“
Wall thickness can measure ~ 3 mm or greater
An appendicolith may be present which will cast an acoustic shadow
Perforated appendix is demonstrated when the appendicular wall has ruptured producing fluid or a newly formed abscess.
The appearance is hyperechoic with an echo-poor abscess surrounding the appendix.
There may be a reflective omentum around the appendix, a thickened bowel, and enlarged lymph nodes.
Asymmetrical wall thickening may indicate perforation. free fluid in the periappendiceal region

Happy scanning!

An Appi a Day