#Intussusception

A Bowel Inside a Bowel: Intussusception

The Case

A 14 month-old female with no significant PMH who presented to the Emergency Department with vomiting. Per mom, patient was well yesterday, but today has been refusing food, crying and vomiting. Patient has had no known sick contacts and her vaccinations are up to date. A review of systems was performed and was otherwise negative.

Physical Exam

Vital signs were within normal limits. Patient was listless with decreased responsiveness, but not in distress. No evidence of respiratory compromise. Abdominal exam was unremarkable, with no focal tenderness and no guarding, rigidity or rebound. During the time the examiner was present in the room, the patient had one episode of crying inconsolably and then vomiting.

An abdominal ultrasound was performed and the diagnosis was revealed to be Intussusception

Ultrasound

Ultrasound has been shown to be 97.9% sensitive and 97.8% specific for diagnosing ileocolic intussusception. To evaluate for intussusception, start with the high frequency low penetration linear transducer. In most young children this transducer will provide adequate depth. In an older child, you may have to use the higher penetration curvilinear transducer. If available, use warm gel to minimize patient discomfort and thereby increasing your changes of obtaining clear images. Begin in the transverse plane and slide your probe up to the right upper quadrant, across, and then down the left side, interrogating for the intussusception (Figure 1).

Figure 1: Suggested path of the ultrasound transducer to evaluate for intussusception.  (https://www.acep.org/how-we-serve/sections/emergency-ultrasound/news/september-2018/pediatric-emergency-ultrasound-deep-dive-on-pocus-for-intussusception/)

Figure 1: Suggested path of the ultrasound transducer to evaluate for intussusception.

(https://www.acep.org/how-we-serve/sections/emergency-ultrasound/news/september-2018/pediatric-emergency-ultrasound-deep-dive-on-pocus-for-intussusception/)

Most of the intussusceptions will be found on the right hand side, and are described as a “target sign” when you are viewing the intestinal intussusception in transverse or the “sandwich sign” in long axis.  The “lawn-mower” approach can be used, similar to the approach for SBO, and graded compression along your path can help move bowel gas out of the way to better evaluate the intestine. The hyperechoic rings are the mucosa and muscularis and the hypoechoic portion is the submucosa.  

Case Discussion

Intussusception is the most common abdominal emergency in early childhood, with the majority of cases occurring in patients <2 years of age. It occurs when the bowel telescopes in on itself and gets stuck. The peristaltic waves of the bowel causes waves of pain in the patient. The classic triad is described as pain, vomiting and bloody stools. Ultrasonography is the preferred diagnostic modality to evaluate for intussusception, given the high sensitivity and specificity (97.9% and 97.8% respectively) when performed by a skilled clinician. Ultrasound also has a high negative predictive value (approaching 99.7%) and can rule out intussusception in a majority of patients. Intussusception presents on ultrasound as a peripheral hypoechoic ring surrounding a central echogenic focus described as either a "target sign” or a “doughnut sign.” (Figure 2a) The visualized doughnut represents the layers of the intestinal wall that have invaginated into themselves. Color doppler can be applied to evaluate for tissue ischemia. (Figure 2b) The most common type of intussusception, ileocolic (as in this case) is usually found in the right lower quadrant. There is usually associated focal tenderness in the right lower quadrant (though this patient was non-tender). Treatment of a non-perforated intussusception typically consists of reduction via air enema, but sometimes operative management is indicated.

Figure 2: Ultrasound image of intussusception

Figure 2: Ultrasound image of intussusception

Intussusception Deception: An Atypical Presentation

THE CASE

A previously healthy 10 year-old male presents with one day of RLQ pain and vomiting.  He awoke earlier that morning with mild to moderate pain, ate oatmeal for breakfast, and then vomited twice. About one hour later, he was sitting at his desk at school when he suddenly developed more severe abdominal pain. He initially presented to his pediatrician’s office, and was subsequently referred to Hasbro Children’s Hospital Emergency Department. No known sick contacts and no recent travel outside Rhode Island. No prior surgeries. He denies fever, chills, respiratory symptoms, melena or hematochezia, diarrhea, or urinary symptoms.

On exam, BP 115/71, HR 80, Temp 98.5F, RR 20, SpO2 99%. He is ill-appearing and acutely distressed. He has RLQ tenderness to palpation and involuntary guarding. He has normal testicular lie without tenderness, edema or erythema.  

DIAGNOSTIC STUDIES

Lab studies notable for WBC 7.9, blood glucose 114.

Abdominal/appendiceal ultrasound was ordered and showed an enteroenteric intussusception in the RLQ with adjacent inflammation and free fluid concerning for possible focal perforation (Figure 1).

Figure 1. “Crescent in a donut” sign. Transverse view of intestinal intussusception. The hyperechoic crescent is formed by mesentery that has been dragged into the intussusception.

Figure 1. “Crescent in a donut” sign. Transverse view of intestinal intussusception. The hyperechoic crescent is formed by mesentery that has been dragged into the intussusception.

DISCUSSION

Intussusception occurs when a part of the bowel invaginates into itself, causing venous and lymphatic congestion. Untreated, intussusception may lead to ischemia and perforation.

Classic Presentation

Intussusception most commonly occurs in infants and toddlers ages 6 to 36 months-old, and approximately 80 percent of cases occur in children younger than 2 years-old [1]. Classically, parents report 15-20 minute episodes, during which their child seems acutely distressed, characterized by vomiting, inconsolable crying, and curling the legs close to the abdomen in apparent pain. They may also describe a “normal period” between episodes or offer a history that includes grossly bloody stools.

75 percent of cases of intussusception in young children have no clear trigger. Some evidence suggests that viral illness plays a role, particularly enteric adenovirus, which is thought to stimulate GI tract lymphatic tissue, in turn causing Peyer’s patches in the terminal ileum to hypertrophy and act as lead points for intussusception [2].

Atypical Presentation

Approximately 10 percent of intussusceptions occur in children older than 5 years [3]. Unlike their younger counterparts, these patients tend to present atypically, with pathologic lead points that triggered the event [4]. The patient described above illustrates this well. At 10 years-old, he presented with peritonitis after his intussusception caused focal perforation, and had no prior history of colicky abdominal pain or bloody stools. Ultimately, he was found to have Meckel’s diverticulum. This is the most common lead point among children, but other causes include polyps, small bowel lymphoma, and vascular malformations [5].

Figure 2. Elongated soft tissue mass. Case courtesy of A.Prof Frank Gaillard,  radiopaedia.org

Figure 2. Elongated soft tissue mass. Case courtesy of A.Prof Frank Gaillard, radiopaedia.org

Diagnostic Testing

Plain abdominal radiographs are not sufficient to rule out intussusception, but they can be useful to exclude perforation and ensure that non-operative reduction by enema is safe.  Some signs of intussusception on abdominal x-ray include an elongated soft tissue mass (classically in the right upper quadrant as in Figure 2) and/or an absence of gas is the distal collapsed bowel, consistent with bowel obstruction.

The optimal diagnostic test for intussusception depends on the patient’s presentation. When infants or toddlers present classically with intermittent severe abdominal pain and no signs of peritonitis, air or contrast enema is the study of choice because it is both diagnostic and therapeutic (Figure 3).

Figure 3. Intussusception treat with air enema. Case courtesy of Dr Andrew Dixon,  radiopaedia.org

Figure 3. Intussusception treat with air enema. Case courtesy of Dr Andrew Dixon, radiopaedia.org

When the diagnosis is unclear, however, abdominal ultrasound is preferred. Ultrasound has been shown to be 97.9% sensitive and 97.8% specific for diagnosing ileocolic intussusception, and is increasingly becoming the initial diagnostic study of choice at some institutions [6,7]. In addition to the ultrasound finding of “crescent in a donut” shown above, other sonographic signs of intussusception include the “target sign” (Figure 4) and the “pseudokidney sign” (Figure 5).

Figure 4. Target Sign. Transverse view of the intestinal intussusception. The hyperechoic rings are formed by the mucosa and muscularis, and the hypoechoic bands are formed by the submucosa. Case courtesy of A.Prof Frank Gaillard,  radiopaedia.org

Figure 4. Target Sign. Transverse view of the intestinal intussusception. The hyperechoic rings are formed by the mucosa and muscularis, and the hypoechoic bands are formed by the submucosa. Case courtesy of A.Prof Frank Gaillard, radiopaedia.org

Figure 5. Pseudokidney sign. Longitudinal view of intestinal intussusception. This view of the intussuscepted bowel mimics a kidney. Case courtesy of A.Prof Frank Gaillard,  radiopaedia.org

Figure 5. Pseudokidney sign. Longitudinal view of intestinal intussusception. This view of the intussuscepted bowel mimics a kidney. Case courtesy of A.Prof Frank Gaillard, radiopaedia.org

Treatment

Without clinical or radiographic signs of perforation, non-operative reduction is first-line treatment. Operative intervention is indicated when the patient is acutely ill, has a lead point needing resection, or the intussusception is in a location unlikely to respond to non-surgical management. For example, small bowel intussusceptions are less likely than ileocolic intussusceptions to respond to non-operative techniques [8].  


CASE CONCLUSION

The patient was taken emergently to the OR, where he underwent exploratory laparoscopy with laparoscopic appendectomy and resection of a Meckel’s diverticulum. No intussusception was noted intraoperatively.  He recovered well, and was discharged home two days later.


A BIT MORE ABOUT MECKEL’S DIVERTICULUM

Meckel’s diverticulum is the most common congenital anomaly of the GI tract. It is a true diverticulum (meaning it contains all layers of the abdominal wall) that is a persistent remnant of the omphalomesenteric duct, which connects the midgut to the yolk sac of the fetus. The “rule of twos” is the classic mnemonic to recall some other important features: it occurs in approximately 2% of the population; the male-to-female ratio is 2:1; it most often occurs within 2 feet the ileocecal valve; it is approximately 2 inches in size; and 2-4% of patients will develop complications related to Meckel’s diverticulum (such as intussusception), usually before age 2 [9].


TAKEAWAY POINTS

  • Consider intussusception in older patients. While it is less likely, approximately 10% of cases occur in patients over 5 years old.

  • In older patients, suspect pathological lead points, such as Meckel’s diverticulum, as potential etiologies of intussusception.

  • Obtain an abdominal x-ray before performing diagnostic/therapeutic enema to rule out perforation.

  • Ultrasound is the preferred test when the diagnosis is uncertain.

  • Patients with small bowel intussusceptions or known lead points are less likely to respond to non-operative reduction.

  • Patients who are acutely ill-appearing require surgery as first-line treatment.


Faculty Reviewer: Dr. Jane Preotle


SOURCES

  1. Intussusception: clinical presentations and imaging characteristics.. Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/22929138

  2. Adenovirus infection and childhood intussusception. - NCBI. Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/1415074

  3. Surgical approach to intussusception in older children: influence of .... Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/25840080

  4. The clinical implications of non-idiopathic intussusception. - NCBI. Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/9880737

  5. The leadpoint in intussusception. - NCBI. Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/2359000

  6. Pediatric Emergency Medicine-Performed Point-of-Care Ultrasound. Retrieved June 22, 2018, from http://www.annemergmed.com/article/S0196-0644(17)31265-9/fulltext

  7. Comparative Effectiveness of Imaging Modalities for the Diagnosis .... Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/28268146

  8. Small bowel intussusception in symptomatic pediatric patients - NCBI. Retrieved June 22, 2018, from https://www.ncbi.nlm.nih.gov/pubmed/11910476

  9. Sagar, Jayesh, Vikas Kumar, and D. K. Shah. "Meckel's diverticulum: a systematic review." Journal of the Royal Society of Medicine 99, no. 10 (2006): 501-505.