Intus - SUS - ception

Written by: Dr. Megan Varghese

Edited by: Dr. Joann Hsu

Case 

Patient is a 20 month old male presenting with two days of vomiting, and two episodes of non-bloody diarrhea. Otherwise, no fever, cough, congestion, or other systemic symptoms.


Vitals: HR 148, BP 95/58, RR 42, O2 sat 100%, rectal temp: 36C

Physical: pale, ill-appearing, dry mucous membranes, tachypneic with clear lungs, extremities were cool with delayed cap refill.



Intussusception  : Background

  • Intussusception occurs when one portion of the intestine invaginates, or telescopes, into another adjacent portion.

  • This leads to a blockage of the bowel, causing symptoms like severe abdominal pain, vomiting, and bloody stool in some cases.

  • It is most common in infants and young children less than 2 years of age, with peak incidence between 3 months and 1 year of age, but can also occur in adults. (1)

Why does this happen? 

  • Peyer's patches are found in the submucosa of the distal portion of the small intestine, with 50% in the ileum. They are lymphoid follicles which get inflamed during a viral/bacterial infection, leading to intussusception. (2)

  • A common etiology is Henoch Schonlein Purpura colitis.

  • In older children and adults who have recurrence, etiology is from a lead point including polyps, Meckel’s diverticulum, and tumors. 

Intussusception: Presentation

  • Signs and symptoms can vary by age group and time to treatment.

  • The most common in all age groups is abdominal pain, which can be hard to decipher from those < 3 years of age.

  • Grossly bloody stools, commonly seen on board questions, are only present in less than 50% of cases, with highest prevalence in <12 mo, present in 83% of this population, and only 37% to 41% in >12 mo.

  • Other more common symptoms are non bilious emesis, guaiac positive stools, lethargy, and irritability.

  • Rarer symptoms with prevalence of <40% are bilious emesis, abdominal mass, and diarrhea. (3)


Intussusception: Imaging

  • Abdominal X-Ray: Specific, not sensitive, and most common finding is “non-specific bowel gas pattern,” while presence of air in the ascending colon on a three view XR series (prone, supine and lateral decubitus) may effectively rule out intussusception in patients with low suspicion for the diagnosis.(4)

    • There are specific findings including:

      • Absent Liver edge: Soft tissue mass in RUQ 

      • Target Sign: Seen in transverse plane

      • Crescent Sign: Head of the intussusception 

  • Ultrasound

    • While X-rays may be helpful, ultrasound is the diagnostic modality of choice.

    • In experienced hands, ultrasonography has excellent test characteristics with both sensitivity and specificity of >97% and a negative predictive value of 99.7%.(3) 

    • At the bedside, pediatric emergency physicians with limited and focused training are also able to accurately diagnose ileocolic intussusception with a sensitivity of 85% and a specificity of 97%.

Intussusception on ultrasound

  • Ileocolic intussusception accounts for 90% of intussusception cases.

  • Features that favor ileocolic over ileo ileal intussusception are a presence of a hyperechoic core, a larger anteroposterior diameter (mean 2.6 cm vs. 1.4 cm), and greater length of intussusceptum (>3 cm strongly favoring ileocolic). (5)

  • Remember the clinical distinction between ileocolic and ileo ileal intussusception - when only small bowel is involved, it is typically an incidental finding and resolves without intervention. These lesions are smaller and do not meet the criteria for ileocolic intussusception as detailed above.

  • Most commonly found in RLQ.

Aiming for Success:

  • Use warm gel, supine on parents lap

  • linear probe

  • Start in RLQ using a lawnmower technique in both transverse and sagittal planes. 

  • Depth should be atleast 5-6 cm.  

  • Graded compression to move bowel gas 

  • Asses for free fluid

  • Asses for bowel wall ischemia with Color Doppler 


Transverse View: “Target Sign” - layers of the intestine 

Longitudinal: “Sandwich Sign” 

Limitations: 

  • Infectious or inflammatory colitis can be misinterpreted for multiple layers of bowel wall seen in intussusception.

  • Intermittent intussusception can be missed if it self-reduces before the scan, and can recur after official US is obtained.

  • All scans are also operator dependent. 


Management

  • Water / Air enema (pediatric Radiologist performs): Also diagnostic. Resolves intussusception in 90% of cases. Cannot be used if there is evidence of bowel perforation. If it recurs after treatment, surgery team should be consulted.

  • Surgery: manually fixes intussusception, remove any tissue that's ischemic, remove a lead point. If the patient is toxic-appearing, surgery is the main management.  (6)

  • In stable, asymptomatic patients with ileo-ileal intussusception, short length of intussusception <2.3 cm, expectant management is reasonable as many of these cases will resolve spontaneously.


Our Patient: 

  • Patient ultimately was admitted to PICU where he was discovered to have multiple lab abnormalities.

  • Official radiology-performed ultrasound failed to redemonstrate findings shown above from our ED ultrasound.

  • Patient tested positive for multiple gastrointestinal infections.

  • He was treated successfully medically and was discharged after a short hospital stay.  

Take Home Points 

  1. Intussusception is the most common cause of intestinal obstruction in children under 2 years of age and should be on the differential for any fussy baby without an obvious source

  2. Set up for success for the ultrasound, looking for the target / sandwich sign 

  3. Repeat ultrasound in patients you have a high clinical suspicion for intussusception. 





References

  1. Mojica, Michael. “Intussusception – Core EM.” Core EM, 8 February 2019, https://coreem.net/core/intussusception/. Accessed 15 March 2024.

  2. Patel, Amar R. “Case of Irreducible Ileocecal Intussusception Due to Leiomyoma of the Colon.” NCBI, 6 September 2019, https://www.ncbi.nlm.nih.gov/pmc/articles/PMC6820895/. Accessed 15 March 2024.

  3. Bulloch, Blake. “Intussusception: clinical presentations and imaging characteristics.” PubMed, 2012 https://pubmed.ncbi.nlm.nih.gov/22929138/. Accessed 15 March 2024.

  4. Dayan, Peter S. “Accuracy of plain radiographs to exclude the diagnosis of intussusception.” PubMed, https://pubmed.ncbi.nlm.nih.gov/22929143/. Accessed 16 March 2024.

  5. Lioubashevsky N, Hiller N, Rozovsky K, Segev L, Simanovsky N. Ileocolic Versus Small-Bowel Intussusception in Children: Can US Enable Reliable Differentiation? Radiology. 2013;269(1):266-71

  6. “Intussusception - Diagnosis & treatment.” Mayo Clinic, https://www.mayoclinic.org/diseases-conditions/intussusception/diagnosis-treatment/drc-20351457. Accessed 16 March 2024.

Booth EM