UOTW: Pediatric Intussusception
Authors: Cristina Gonzalez, MS4 and Alec Small, DO
Edited by Christopher Parker, DO, and Molly Hartrich, MD
A 4-year-old boy with speech delay presents with his grandmother to the emergency department (ED) with approximately one week of cough, congestion, runny nose, and one day of vomiting yellow emesis and watery, non-bloody diarrhea. He is unable to verbalize any complaints, but his grandmother notes he may have abdominal pain. He last ate, urinated, and defecated yesterday. On examination, he appears weak, occasionally crying in bed, and prefers to be in a knee-to-chest position. He is tachycardic but with otherwise reassuring vitals. Abdomen is soft, non-distended, and non-peritonitic, but it is difficult to appreciate tenderness due to the patient's fussiness and non-verbal status.
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This is the classic POCUS finding for intussusception, the target sign (i.e., bull’s eye), which describes the appearance of the layers of intestines telescoped inside one another (Figure 1).
Figure 1. Cross sectional ultrasound image of intussusception. Red circles are highlighting the bull’s eye or target sign, with a loop of bowel sitting within another bowel segment.
Figure 2. Longitudinal ultrasound image of intussusception, demonstrating intussusceptum and intussuscipiens.
Figure 3. Ultrasound features of intussusception. (a) Target sign, seen in a transverse section through the intussusception with a loop of edematous bowel sitting within another bowel loop. (b) Pseudo-kidney sign, seen in a longitudinal section through the intussusception with the intussusceptum seen passing through the distal segment of bowel. (1)
Emergency practitioners caring for pediatric patients who present to the ED with abdominal pain must first consider life-threatening diagnoses, such as bowel obstruction, appendicitis, cholecystitis, or diabetic ketoacidosis. Ultrasound is commonly used to evaluate abdominal pain and is considered first-line for detecting pediatric intussusception, a common cause of obstruction in children. Ultrasound findings of the target sign, usually ≥ 3 cm in diameter, or pseudo-kidney sign indicate a high likelihood of intussusception (Figure 2 and 3). However, it should be emphasized that appendicitis is a more common cause of acute abdominal emergency than intussusception, and perforated appendicitis can be confused for intussusception, as the fat surrounding the appendix can appear hyperechoic due to inflammation. , POCUS is nonetheless quite accurate for diagnosing intussusception in children. Pediatric emergency medicine providers with only one hour of training can detect intussusception with a sensitivity of 85% and specificity of 97%. Furthermore, ultrasound performed by experienced sonographers has a sensitivity and specificity of nearly 100%.
If signs of intussusception are seen on POCUS and the patient’s symptoms are mild – meaning the child does not exhibit bilious vomiting, dark red (currant jelly) stool, lethargy, altered mental status, or symptoms of shock ¬– the first step is to repeat the ultrasound formally to see if the findings persist, because most small bowel intussusceptions will spontaneously reduce. (4) If the findings persist, radiology will attempt reduction with pneumatic and/or hydrostatic enema, and if unsuccessful, then surgery may be indicated. (9)
Bedside ultrasound showed target sign and an area of thickened bowel. A formal ultrasound was ordered but did not find any evidence of intussusception or secondary signs of acute appendicitis The radiologist reviewed the POCUS performed in the ED and agreed that they were consistent with intussusception. The patient was admitted for monitoring overnight and his condition improved. He was discharged the next day without any complications.
 Bradshaw CJ, Johnson P. Intussusception. Surgery (Oxford). 2022;40(5):311-315. doi:10.1016/j.mpsur.2022.03.001.