PEM POCUS Series: Intussusception

Read this tutorial on the use of point of care ultrasonography (POCUS) for pediatric intussusception. Then test your skills on the ALiEMU course page to receive your PEM POCUS badge worth 2 hours of ALiEMU course credit.

 


PATIENT CASE

Johnny is a 2-year-old boy who comes into the emergency department for abdominal pain for the last day. His parents are concerned that he has been having intermittent abdominal pain and has seemed very tired all day. Parents deny bloody stool.

On arrival, his vital signs are:

Vital SignFinding
Temperature36.9C
Heart rate110 bpm
Blood pressure97/50
Respiratory rate22
Oxygen saturation (room air)99%

He is tired appearing, and his abdominal exam is soft but diffusely tender. Given his intermittent abdominal pain, you decide to perform an intussusception point of care ultrasound (POCUS) exam.

ULTRASOUND TECHNIQUE

Intussusception is when one part of the bowel telescopes, or gets stuck, in another part of the bowel. Typically intussusception refers to ileocolic intussusception where the ileum becomes stuck in the colon. To perform the ultrasound, start in the right lower quadrant and trace the colon. See below for a step-by-step technique.

intussusception
Overview of sequential ultrasound transducer positioning on the anterior abdomen to assess for intussusception

Technique

  • The patient should be positioned supine.
  • To aid in comforting the child, the child can be positioned supine in the parent’s lap while undergoing the scan. Having the parent or another provider offer a toy, book, or phone/tablet to distract the child during the scan can also help ease anxiety.
  • Begin in the right lower quadrant (RLQ), using a high frequency linear probe with the probe marker to patient’s right.
  • First, identify the anatomical landmarks in the RLQ (see ultrasound images below):
    • Psoas muscle (green) laterally
    • Right iliac vessels (blue)
    • Abdominal muscles (red)
    • Bladder (yellow) medially

Ultrasound image: Anterior Abdomen (RLQ) View

intussusception RLQ ultrasound

Ultrasound Image: Anterior Abdomen RLQ (More Medial) View

PEM POCUS intussusception RLQ More Medial
  • Perform graded compression, with slow steady pressure to displace bowel gas
  • Follow the colon from the RLQ to right upper quadrant (RUQ) until the liver (purple) and gallbladder are identified

Ultrasound Image: Anterior Abdomen (RUQ) View

PEM POCUS intussusception RUQ
  • Rotate the probe marker to patient’s head and scan the entire length of the transverse colon.
  • Rotate the probe marker back to patient’s right and scan the entire length of the descending colon, making sure to scan all four quadrants.
  • Save representative video clips and still images of each quadrant.
  • If an intussusception is found, measure its diameter in transverse view and note in which quadrant(s) it is found.
  • At the end of scan, if you have found an intussusception, re-image the abdomen to make sure it was not transient.
  • The provider should maintain awareness of the patient’s comfort throughout the scan.

INTUSSUSCEPTION CLASSIC FINDINGS

Normal (no intussusception)

https://www.youtube.com/watch?v=6TYEo1jZUwU&feature=emb_title
Normal: There is no target or sandwich sign, but rather just folded normal bowel. (To replay, press circular arrow in bottom left corner)

Abnormal findings

  • Look for findings of a sandwich sign (or pseudo-kidney sign) in the longitudinal view and target sign (or donut sign) in the transverse view.
  • If visualized, measure the diameter of the intussusception in short axis (transverse) and note which in which quadrant(s) it is located.

Sandwich Sign

https://www.youtube.com/watch?v=MK3WvUbdsgM&feature=emb_title
Anterior abdomen ultrasound: Intussusception – Presence of a sandwich sign (long axis view) and target sign (short axis view)

Target Sign

Intussusception diameter ultrasound
Measurement: The diameter of an intussusception (i.e., target sign) in transverse view involves measuring the distance from outer wall to outer wall.

Additional Anterior Abdominal Ultrasound Videos

Pro Tip
It can be difficult to distinguish intussusception of the small bowel-small bowel (i.e., when the ileum or part of the small bowel telescopes into itself) versus ileocolic (i.e., when the ileum becomes telescopes into the colon). The former often does not require a procedure for reduction, while the latter typically does. If the target sign diameter is <2 cm and transient, a small bowel-small bowel intussusception should be suspected. The length of the intussusception, or how many quadrants are involved, can also be measured for an idea of how much bowel is involved.

Small bowel-small bowel intussusception

https://www.youtube.com/watch?v=Po7wef5sVFw&feature=emb_title
Small bowel-small bowel intussusception – Note the small size of the target lesion. Because the ultrasound video scans to a depth of 3.3 cm (see bottom right side of the screen), the target sign appears to be approximately only 1 cm in diameter.

 

https://www.youtube.com/watch?v=AFrdsZFIV_U&feature=emb_title
Small bowel-small bowel intussusception – There is a target sign, but it is small (<2 cm) with a small fat (white) core.

 

Ileo-colic intussusception

https://www.youtube.com/watch?v=Iw3UQfLBmPo&feature=emb_title
Ileo-colic intussusception with classic target sign – Note the lymph nodes (black) inside the mesenteric fat (white) in the center of the target.

FACTS and LITERATURE REVIEW

Mimickers of Intussusception

There are additional pathologies that can be mistaken for intussusception such as an intussuscepted appendix, appendicitis surrounded by abscess, and Meckel’s diverticulum, which are beyond the scope of this course. Any concerning finding for intussusception should be followed by a confirmatory study by the radiology department.

Benefits of intussusception POCUS scans

Although few studies have looked at point of care ultrasonography (POCUS) for intussusception, the existing studies have shown excellent test characteristics and a decreased length of stay with using POCUS.

Two studies assessed the test characteristics of the intussusception POCUS.

PublicationStudy MethodologySensitivitySpecificity
Riera et al. (2012)​1​This journal publication was a prospective study of 82 patients who underwent POCUS by pediatric emergency medicine (PEM) providers. The gold standard was a comprehensive radiology ultrasound.85%97%
Trigylidas et al. (2017) ​2​This abstract reported a retrospective study of 105 intussusception POCUS scans by PEM providers. The gold standard was either a direct radiology over-read of the POCUS scans or a radiology department ultrasound.96.2%92.6%
Lin-Martore et al. (2020)6This systematic review and meta analysis included 1,303 patients and 6 studies.94.9%99.1%
Bergmann et al. (2021)7This prospective study of 256 children across 17 sites (35 sonologists) compared POCUS and radiology performed ultrasound using a gold standard of clinically important intussusception which was defined as an intussusception that required radiographic or surgical reduction during or within 7 days of the incident ED visit.96.6%98%

In terms of ED length of stay (LOS), Kim et al. (2017) reported that after the introduction of an intussusception POCUS scanning protocol, the LOS decreased by >200 minutes.​3​

Differentiating small bowel-small bowel from ileocolic intussusception

In general, true ileocolic intussusceptions are:

  • Found on the right side of the abdomen
  • >2 cm in diameter
  • Have mesenteric fat (which is white) and lymph nodes in the center
  • Do not self resolve

There have been studies looking at distinguishing small bowel-small bowel from ileocolic intussusception. These, however, have been radiology-based and not POCUS studies, making generalizability to the ED setting challenging. Thus, if there is a concern for an intussusception, a radiology ultrasound should be ordered.

One small study with 27 patients by Wiersma et al. (2006) found that small bowel-small bowel intussusceptions had a smaller mean diameter and length compared to ileocolic intussusceptions.​4​

Type of intussusception# of patients and scansMean diameter (range)Mean length (range)Location
Small bowel-small bowel10 patients, 11 scans1.5 cm (1.1-2.5 cm)2.5 cm (1.5-6 cm)Distributed throughout the abdomen (6 paraumbilical, 2 RUQ, 2 RLQ, 1 LLQ)
Ileocolic14 patients, 16 scans3.7 cm (3-5.5 cm)8.2 cm (5-12.5 cm)All on right side of abdomen

Lioubashevsky et al 2013​5​ had a larger sample size (174 patients) with similar findings. The authors also measured the ratio of the inner fat core to the intussusception outer wall and identified the presence or absence of lymph nodes within the lesion.

Type of Intussusception# of patientsMean diameter (range)Mean length (range)Ratio of fat core to the intussusception outer wall% of patients with lymph nodes in the lesion
Small bowel-small bowel57 patients1.4 cm 
(1.1-2.5 cm)
2.5 cm 
(1.5-6 cm)
<114%
Ileocolic143 patients2.6 cm 
(1.3-4 cm)
8.2 cm 
(5-12.5 cm)
>189.5%

References [click to expand] +

  1. Riera A, Hsiao A, Langhan M, Goodman T, Chen L. Diagnosis of intussusception by physician novice sonographers in the emergency department. Ann Emerg Med. 2012;60(3):264-268. PMID 22424652
  2. Trigylidas TE, Kelly JC, Hegenbarth MA, Kennedy C, Patel L, O’Rourke K. 395 Pediatric Emergency Medicine-Performed Point-of-Care Ultrasound (POCUS) for the Diagnosis of Intussusception. Annals of Emergency Medicine. October 2017:S155. DOI
  3. Kim J, Lee J, Kwon J, Cho H, Lee J, Ryu J. Point-of-Care Ultrasound Could Streamline the Emergency Department Workflow of Clinically Nonspecific Intussusception. Pediatr Emerg Care. September 2017. PMID 28926507
  4. Wiersma F, Allema J, Holscher H. Ileoileal intussusception in children: ultrasonographic differentiation from ileocolic intussusception. Pediatr Radiol. 2006;36(11):1177-1181. PMID 17019589
  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):266-271. PMID 23801771
  6. Lin-Martore M, Kornblith AE, Kohn MA, Gottlieb M. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception in Children Presenting to the Emergency Department: A Systematic Review and Meta-analysis. West J Emerg Med. 2020 Jul 2;21(4):1008-1016. doi: 10.5811/westjem.2020.4.46241. PMID: 32726276.
  7. Bergmann KR, Arroyo AC, Tessaro MO, et al; P2Network. Diagnostic Accuracy of Point-of-Care Ultrasound for Intussusception: A Multicenter, Noninferiority Study of Paired Diagnostic Tests. Ann Emerg Med. 2021 Jul 2:S0196-0644(21)00340-1. doi: 10.1016/j.annemergmed.2021.04.033. Epub ahead of print. PMID: 34226072.

Case Resolution

You place a linear, high-frequency probe on the right side of the patient’s abdomen. You perform a bedside ultrasound scan, viewing transversely and longitudinally through the upper and lower abdomen. You observe the following:

https://www.youtube.com/watch?v=tQRLWPc8Heo

What is the diagnosis?

This is an intussusception!

The intussusceptum (red) is the part of the bowel that has telescoped into the intussuscipiens (blue). When ileum becomes trapped in the colon, this can lead to ischemia and necrosis over time. This is what causes the classic “currant jelly stools”, which are bloody stools.

Tip: The classic triad of colicky abdominal pain, palpable mass and bloody stool are present in less than 50% of patients, and intussusception should be suspected for patients with vomiting, abdominal pain, and/or lethargy.​1​

Hospital course

Johnny underwent an air enema reduction in the Radiology department, which successfully reduced the ileocolic intussusception.

Reference

  1. Daneman A, Alton D. Intussusception. Issues and controversies related to diagnosis and reduction. Radiol Clin North Am. 1996;34(4):743-756. PMID 8677307.

The PEM POCUS series was created by the UCSF Division of Pediatric Emergency Medicine to help advance pediatric care by the thoughtful use of bedside ultrasonography.

Learn more about bedside ultrasonography on the ALiEM Ultrasound for the Win series

By |2021-07-31T07:17:48-07:00May 10, 2021|Gastrointestinal, PEM POCUS, Ultrasound|

SAEM Clinical Image Series: Distended Abdomen after ROSC

distended abdomen

A 64-year-old female presented to the emergency department (ED) in cardiac arrest. Her family members heard her fall in the bathroom and started CPR. EMS intubated the patient and 20 minutes of CPR was done en route. Return of spontaneous circulation (ROSC) was achieved after fifteen minutes of resuscitation in the ED.

At baseline, the patient ambulated with her walker and was conversant. She was having abdominal pain and nausea for the past three days after recently being diagnosed with a urinary tract infection. On arrival to the ED, the patient was pulseless with ventricular fibrillation. The patient received ten doses of epinephrine, two doses of sodium bicarbonate, calcium, amiodarone, magnesium, and one dose of naloxone during the resuscitation. One defibrillatory shock was administered. She was started on a norepinephrine drip and an amiodarone drip.

Computed tomography (CT) of the head was negative. CT of the chest was significant for left pneumothorax and left-sided subcutaneous emphysema. A pigtail chest tube was placed. After a few hours, she developed worsening abdominal distension. An abdominal CT scan revealed the images shown.

(more…)

SAEM Clinical Image Series: An Oropharyngeal Mass

oropharyngeal mass

A fifty-year-old male presented to the emergency department (ED) unconscious with CPR in progress. Per EMS report, the patient was found down surrounded by emesis with no pulse or respirations. Fifteen minutes of CPR was performed prior to arrival in the ED with a King Tube in place. The King Tube was filled with emesis and increasingly difficult to bag. The King Tube was removed to attempt intubation and maximize oxygenation and ventilation.

When the Mac 4 blade was placed in the mouth, a large, pink, fleshy, and vascularized structure was seen in the mouth just anterior to where the uvula should have been located.  Attempts were made to compress the mass into the tongue, separate the tongue from the mass, and sweep the mass out of the way. All attempts failed to expose the epiglottis. An attempt was made to remove the mass, but it appeared to be part of the mouth.  The decision was made to proceed with a cricothyrotomy; a 6.0 tube was successfully placed, and the patient was able to be ventilated. Return of spontaneous circulation was never achieved and the patient expired in the ED.

(more…)

Unlocking the MIC-KEY: Understanding and Troubleshooting Low-Profile Gastrostomy Tubes

You are working an overnight clinical shift at your community emergency department when a worried mother brings in her 15-year-old child with cerebral palsy due to their gastric tube “coming out.” As you begin to obtain a history of the patient’s gastric tube (when it was placed, where it was placed, why is it in place, etc.) you realize you will be the one replacing it tonight, and frankly you haven’t done this before. The following post serves as a refresher on the use, placement, and complications of gastrostomy tubes.

(more…)

By |2020-08-23T17:00:00-07:00Aug 24, 2020|Emergency Medicine, Gastrointestinal|

Diagnose on Sight: Scrotal Swelling

pneumoscrotum

Case: A 58-year-old male with no past medical history presents to the emergency department for evaluation of right lower quadrant abdominal pain associated with right scrotal swelling. The patient reports that he had a colonoscopy the day before to remove a 20 mm polyp, which had been seen on an outpatient CT scan. He states that he noticed that his right scrotum appeared slightly swollen immediately away after the procedure, but since then the swelling had increased and he developed mild right lower quadrant abdominal pain. Physical examination reveals mild tenderness to the right lower quadrant and swelling of the right scrotum with palpable crepitus of the right scrotum and inguinal canal.  There is no overlying skin discoloration.  What is the most likely diagnosis?

(more…)

Trick of the Trade: Deflate an Undeflatable Gastrostomy Tube

A 54-year-old female with a past medical history of throat cancer presents for gastrostomy tube (G-tube) replacement. The initial G-tube was placed 3 years ago. Most recently, the patient had the G-tube changed 7 months ago. She presents to the Emergency Department because the G-tube is leaking from the tubing that is external to the skin. When you attempt to deflate the cuff, you are unsuccessful.

(more…)

By |2020-02-13T22:46:36-08:00Feb 19, 2020|Gastrointestinal, Tricks of the Trade|

IDEA Series: Just-in-Time Training for Diagnostic Paracentesis

AP wrist radiograph

According to the National Health And Nutrition Examination Survey, approximately 630,000 adults in the United States have cirrhosis of the liver, 69% of which are reportedly unaware of having liver disease. A diagnostic paracentesis is a simple procedure for identifying spontaneous bacterial peritonitis in cirrhotic patients with ascites. A just-in-time training (JITT) model incorporating low-fidelity equipment readily available in the ED can facilitate procedural teaching of the diagnostic paracentesis.

(more…)
By |2019-12-21T13:00:22-08:00Dec 18, 2019|Academic, Gastrointestinal, IDEA series|
Go to Top