Abstract
A 5-month-old infant presented with paroxysmal crying and vomiting for more than 4 h. Ultrasonography confirmed intussusception in the right abdomen, but intraluminal gas limited precise classification. On the assumption of ileocolic intussusception, air enema reduction was attempted but was unsuccessful. Due to the persistence of symptoms, low-dose computed tomography was performed to further characterize the intussusception subtype. The scan demonstrated concentric ring and pseudokidney-like signs within a segment of the ileum, strongly suggesting small-bowel intussusception. Exploratory laparotomy confirmed ileal-ileal intussusception with Meckel’s diverticulum as the pathological lead point. Segmental ileal resection with primary anastomosis was performed, and histopathology demonstrated ectopic gastric mucosa within the diverticulum. The infant recovered uneventfully and remained well at short-term follow-up. This case emphasizes that failed air enema reduction together with indeterminate ultrasonographic subtyping should raise suspicion for a pathological lead point and that low-dose computed tomography should be reserved as a selective diagnostic tool rather than as a routine step in infants with intussusception.
Introduction
Intussusception is a common cause of acute abdominal pain in children. 1 In adults, however, intussusception is uncommon and usually has an identifiable structural cause such as a polyp, 2 a tumor, 3 or a postoperative lesion, whereas pediatric intussusception is most often idiopathic and usually ileocolic. This etiologic contrast is clinically important because the pretest probability of a pathological lead point (PLP) differs substantially between age groups.
In children, most cases occur between 3 and 36 months of age and are managed initially with image-guided enema reduction. Nonetheless, a PLP should be considered when symptoms are prolonged, enema reduction fails, or imaging suggests small-bowel rather than ileocolic disease. Meckel’s diverticulum (MD) is the most common congenital anomaly of the gastrointestinal tract and a well-recognized PLP in pediatric intussusception. 4
We present a case of an infant with ultrasound-confirmed intussusception, in whom the specific subtype could not be clearly determined. After failed air enema reduction and with persistent symptoms, the possibility of a PLP, such as MD, should be considered. In cases where ultrasound fails to delineate the subtype of intussusception, low-dose computed tomography (CT) can serve as a supplementary diagnostic tool, particularly in select circumstances, and may help guide clinical decision-making regarding treatment strategies.
Case presentation
A 5-month-old male infant was brought to the emergency department at 19:15 on December 26, 2025, presenting with intermittent crying and vomiting that had persisted for over 4 h. Physical examination revealed a palpable mass in the right abdomen with tenderness and rebound tenderness, but no abdominal rigidity. The infant had not passed stool and showed no signs of fever or lethargy. The vomitus consisted of gastric contents without blood. There was no history of allergies. Laboratory tests showed normal coagulation, liver and kidney function, and electrolytes. The hematocrit-to-hemoglobin ratio was 3.05 (normal range: 2.80–3.20).
Abdominal ultrasonography (US) revealed a mixed-echogenic mass measuring 2.3 × 1.9 cm in the right abdomen, with an indistinct boundary from the adjacent bowel. Mild edema of the bowel wall was observed in part of the involved segment. On longitudinal and transverse views, the lesion demonstrated the sleeve sign and concentric ring sign, respectively (Figure 1(a) and (b)). Color Doppler US showed no obvious abnormal flow signals. The sonographic findings were suggestive of intussusception; however, due to marked interference from intraluminal bowel gas, the length of the involved segment, the specific subtype of intussusception, and the presence of a definite PLP could not be clearly determined.
Imaging findings. US demonstrating the sleeve sign on the longitudinal view (a, red arrow) and the concentric ring sign on the transverse view (b, green arrow). Low-dose CT demonstrating pseudokidney-like (c, red arrow) and concentric ring (d, green arrow) appearances in a segment of the ileum in the right abdomen, accompanied by focal bowel wall thickening and edema.
Given that ileocolic intussusception (ICI) is the most common subtype in infants, air enema reduction was considered. The infant subsequently underwent air enema reduction under continuous pressure monitoring, with pressures ranging from 4 to 10 kPa (~30–75 mmHg). A total of three attempts were made, each lasting ~3 min. Under fluoroscopy, the mass shadow did not disappear, and no reflux of air across the ileocecal valve into the terminal ileum was observed, indicating failed pneumatic reduction.
In view of the persistent symptoms and to further clarify the subtype of intussusception, low-dose CT was performed while the infant was relatively calm and at rest, after discussion with and consent from the parents. CT demonstrated a concentric ring or pseudokidney-like appearance in a segment of the ileum in the right abdomen, with focal bowel wall thickening and edema, but no evidence of intestinal obstruction, perforation, or ischemic necrosis, suggesting small-bowel intussusception (SBI; Figure 1(c) and (d)). The low-dose CT protocol was as follows: scanning was performed using a Philips CT 6000 scanner (Philips Healthcare, Best, The Netherlands), with a tube voltage of 80 kV and a tube current of 40 mAs. Images were acquired with a slice thickness of 5 mm and an interslice gap of 5 mm, followed by iterative reconstruction at 1.5 mm. No contrast agent was administered. The infant was relatively calm and motionless after soothing, without the need for sedation. Radiation parameters were volume CT dose index (CTDIvol) 3.9 mGy and dose-length product (DLP) 48.75 mGy·cm, consistent with a low-dose CT protocol.
Emergency laparotomy was performed at 1:30 a.m. on December 27, 2025. Intraoperatively, a diverticulum measuring ~1.7 cm in length with a base width of ~1.5 cm was identified on the ileum, ~50 cm proximal to the ileocecal valve, and was considered the lead point of the intussusception (Figure 2(a) and (b)). The intussuscepted bowel wall was edematous and thickened, with focal purplish-red discoloration and mesenteric congestion. Gentle manual reduction was difficult. Subsequently, a segmental ileal resection of ~2.5 cm, including the diverticulum, was performed, followed by primary anastomosis. Histopathological examination confirmed MD, and hematoxylin–eosin staining (×40 magnification) demonstrated ectopic gastric mucosa within the diverticulum (Figure 2(c) and (d)).
Operative and histopathologic findings. Intraoperative photographs demonstrating the intussuscepted ileal segment (a, red arrow) and MD as the PLP (b, green arrow). Hematoxylin–eosin staining at ×40 magnification showed diverticular mucosa (c, d, red arrows) and ectopic gastric mucosa (c, d, green arrows).
Postoperative management was initiated immediately and included fasting, intravenous fluid support, and antibiotic therapy. During the postoperative hospital stay, vital signs remained stable, abdominal distension and vomiting resolved, the wound condition was stable, and there were no signs of fever or peritoneal irritation. The recovery was uneventful, and the infant was discharged on December 30, 2025. At the telephone follow-up 1 week later, the parents reported normal feeding, sleep, wound healing, and general condition, with no recurrent abdominal pain. The detailed timeline is shown in Table 1 (Supplemental Material).
Timeline.
CT: computed tomography; ICI: ileocolic intussusception; MD: Meckel’s diverticulum; SBI: small-bowel intussusception; US: ultrasonography.
Discussion
Although ICI is the most common subtype in infants, 1 this case highlights that epidemiologic probability cannot substitute for individualized subtype assessment. 5 In the present patient, US demonstrated the typical concentric ring and sleeve-like signs, supporting the diagnosis of intussusception, but it failed to reliably distinguish ileocolic from SBI. This limitation was mainly attributable to marked intraluminal gas, poor acoustic windows, and suboptimal cooperation of the infant, which prevented accurate evaluation of the involved bowel length, precise anatomic location, and the presence of a definite PLP. 6 In addition, the sonographic features of SBI and ICI may partially overlap; therefore, without adequate visualization of lesion location, extent, and its relationship to the ileocecal region, the target sign alone is often insufficient for confident subtype classification.
It was also clinically reasonable that, after failed pneumatic reduction, repeat expert US was not prioritized and immediate surgery was not undertaken. Following enema reduction, increased bowel gas, luminal distension, and possible edema of the ileocecal region or involved bowel segment may further aggravate acoustic attenuation and artifacts such that repeated US may still fail to resolve the key unanswered questions. 7 At the same time, failed enema reduction does not necessarily mandate immediate laparotomy. Current evidence indicates that prompt surgical intervention is mainly required in children with perforation, generalized peritonitis, shock, progressive clinical deterioration, or a high suspicion of bowel necrosis. 8 In relatively stable patients with an unclear intussusception subtype, additional imaging may help avoid urgent surgical decision-making based on insufficient anatomical information.
In this context, the main value of low-dose CT was its ability to provide anatomical information that could not be adequately obtained by US. In this case, CT more clearly localized the lesion to the ileal segment in the right abdomen, demonstrating concentric ring and pseudokidney-like signs, as well as focal bowel wall thickening and edema. It also excluded major complications, including overt bowel obstruction, perforation, and ischemic necrosis, thereby supporting the diagnosis of SBI. Although CT is not recommended as a routine first-line examination for pediatric intussusception, it may serve as a selective adjunctive diagnostic tool in specific situations, such as atypical age at presentation, unusual lesion location, failed enema reduction, atypical clinical features, or suspected PLPs, rather than as a routine step after failed enema reduction.9,10 For lead points such as MD, CT may not always directly identify the lesion itself, but it can provide stronger evidence for secondary SBI through findings such as an abnormal traction focus, persistent invaginated bowel layers, lesion location, and associated bowel wall abnormalities. 11
Conclusions
In summary, this case provides a practical clinical strategy: Failed air enema reduction and indeterminate ultrasonographic subtype classification should raise suspicion for a PLP, while low-dose CT should be used as a selective adjunctive diagnostic tool rather than as a routine step for all infants and young children with intussusception.
Supplemental Material
sj-docx-1-sco-10.1177_2050313X261454853 – Supplemental material for Failed air enema reduction leading to the diagnosis of small-bowel intussusception secondary to Meckel’s diverticulum with ectopic gastric mucosa in a 5-month-old infant: A case report
Supplemental material, sj-docx-1-sco-10.1177_2050313X261454853 for Failed air enema reduction leading to the diagnosis of small-bowel intussusception secondary to Meckel’s diverticulum with ectopic gastric mucosa in a 5-month-old infant: A case report by Zheng Wang and Cheng-xin Yu in SAGE Open Medical Case Reports
Footnotes
Acknowledgements
The authors thank all clinicians and staff involved in the diagnosis and care of this patient.
Ethical considerations
According to the policy of the Yichang Central People’s Hospital, formal approval from the ethics committee was waived for this single-patient case report.
Consent to participate
Written informed consent for participation was obtained from the patient’s legal guardians.
Consent for publication
Written informed consent for publication was obtained from the patient’s legal guardians.
Author contributions
Zheng Wang drafted the manuscript, prepared the figures, and analyzed the data. Cheng-xin Yu critically revised the manuscript. All authors reviewed and approved the final manuscript.
Funding
The authors received no financial support for the research, authorship, and/or publication of this article.
Declaration of conflicting interests
The authors declared no potential conflicts of interest with respect to the research, authorship, and/or publication of this article.
Data availability statement
The data are not publicly available because they contain information that could compromise participant privacy.
Reporting guidelines
This case report was prepared in accordance with the CARE reporting guidelines. A completed CARE checklist is provided as a supplementary file. The authors confirm that this case report addresses the key CARE items, including identification as a case report in the title, an unstructured abstract, an introduction, patient information, clinical findings, a timeline, diagnostic assessment, therapeutic intervention, follow-up and outcomes, discussion, and informed consent. Patient perspective was not available because of the patient’s age.
Supplemental material
Supplemental material for this article is available online.
References
Supplementary Material
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