Any list of “Top 10 Emergency Department diagnoses in children you can’t miss” should include intussusception. This episode reviews the diagnosis and management in practical manner that should help you on your next shift. It also features the talents of Kriti Gupta, MD, a Pediatric Emergency Medicine fellow from New York Presbyterian Brooklyn Methodist Hospital who is both the producer and host of this episode.
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Hi everyone, on today’s episode I wanted to chat about intussusception in a nice, easy digestible way (and yes, that pun is very much so intended). I make no promises that there aren’t more of these coming ahead. This is a high yield, board favorite diagnosis, and it serves us well to keep it on our differentials in practice for that next child who presents to our emergency room with abdominal pain.
As always, we must start with the foundations — or as Sherlock Holmes would say if he was a doctor-detective extraordinaire, “it’s alimentary, my dear Watson”. Intussusception is when a segment of bowel invaginates into a more distal segment of bowel. This can theoretically happen anywhere along the intestinal tract within the small and large intestines, but the most common area of occurrence is ileocecal. Sometimes when small bowel to small bowel intussusception (or “ileoileal” intussusception) occurs, even that can eventually run itself into the ileocecal valve.
This clash of bowels can happen for a number of reasons. It’s worth knowing that 90% of cases are idiopathic but it is hypothesized that many occur due to lymphoid hyperplasia in Peyer’s Patches after viral infections (specifically, there exists a correlation with adenovirus); alternatively, bacterial infections from E. coli, Campylobacter, Shigella, and Salmonella have been linked to it as well. In the remaining 10% of cases, there exist what are called “lead points” that drag a segment of bowel to invaginate into another segment. These lead points include (but are not limited to) polyps, a Meckel’s diverticulum, intestinal duplications, intraintestinal tumors, cystic fibrosis due to blockage caused by easier mucus build-up, and Henoch-Schonlein Purpura. Usually, if an intussusception is easily reduced and the child does well, we tend to not go searching for such alternate causes.
We hear the diagnosis be thrown around frequently, but how common is it and when are we most likely to see it? The typical age of presentation is between 3 and 12 months of age (with a peak incidence between 5-9 months). It is therefore the leading cause of acute intestinal obstruction in infants. 80% of cases occur before age 2. Because it tends to happen in younger children, it generally falls out of favor as a top differential diagnosis as the child outgrows toddlerhood.
One board favorite association to be aware of is the link between the oral, live rotavirus vaccine and the occurrence of intussusception in infants. In the 1990’s, the original rotavirus vaccine (called Rotashield) was actually taken off the market and replaced with the current brands used more widely in the United States now, after studies done by the CDC showed that otherwise low risk infants were at increased risk of developing intussusception approximately 2 weeks after the second dose of the vaccine. While this wasn’t statistically significant, the CDC estimated that an additional 1-2 cases per 10,000 vaccinated infants may occur, thereby cautioning pediatricians of this side effect. The new rotavirus vaccines (called RotaTeq and Rotarix) have been studied as well, and there still remains a small increased risk of intussusception after their administration, but less than with the prior vaccine.
Having discussed that, let’s chat about the disease process itself. Children who experience this disease therefore present with a range of symptoms, all of which I’m sure are.. Well, gut-wrenching. You’ll often hear the textbook triad of colicky abdominal pain, bilious emesis, and currant jelly stools. I want to note a couple things about the latter part of this triad, though. The first is that that “bilious” emesis (emphasis on bilious) is a rather rare complaint; initially, the child can certainly have emesis that is nonbilious and reflexive, but you wouldn’t expect it to be bilious until later in the disease course when the invagination creates a more sustained obstruction past the duodenum. Second, be aware of that buzzword we hear everywhere, the infamous “currant jelly stools” (which really has ruined many types of jelly for me, personally) – if there is red stool, know that this, too, is a rather late finding. We’ll discuss the mechanism of why this is the case shortly.
So, let’s dive into the most common complaint in that triad – the abdominal pain. Because the bowel can intermittently invaginate and then go back to normal, the pain tends to be episodic and colicky in nature, which distinguishes it from other common pediatric causes of abdominal pain. This is a child who, if old enough, may be found to draw their knees up to their chest when they experience the pain. In between the episodes, the child can appear to be on a spectrum; they could be described to be anywhere between happy and playful to ill-appearing and listless. This depends largely on how long the intussusception has been going on. Early on, they may appear well in between episodes and may not have the strongest gastrointestinal complaints. However, in patients whose symptoms have been going on relatively longer (think > 48 hours) the intermittent nature of bowel ischemia over time lends itself to the buildup of acidosis. This acidosis renders some children more fatigued and lethargic in between episodes, even at baseline. Lastly, always keep in mind that infants can confuse you with their presentation for a lot of things, including when presenting with intussusception. Sometimes, neurologic complaints like hypotonia or lethargy may present to a stronger degree in this age group. So, the moral of the story here is to always keep intussusception on the differential for a variety of these complaints, including in the altered infant.
Now, let’s talk about physical findings. If we were to catch a child acutely in an intussusception episode, we may palpage a sausage-like mass in the abdomen; typically, this would be in the RLQ or RUQ, depending on which segment of the intestine was affected. We may appreciate abdominal distention, emesis, or possible stool in the rectal vault. We may not see visibly bloody stool, but a fecal occult blood test may turn out positive. If we DO see visibly bloody stool, once again, it is a late finding that indicates significant bowel wall ischemia has occurred. Currant jelly consistency of stool forms when ischemia leads to sloughing of intestinal villi – the “currant” is a combination of sloughed off blood, mucus, and mucosa. It occurs as the intussusception tightens over time, initially compressing mesenteric veins and eventually, mesenteric arteries. Arterial compression lessens the bleeding initially, but with continued arterial involvement, bowels become gangrenous and could even perforate, causing peritonitis.
Now, let’s say you have that child in front of you and find yourself whispering to yourself, “you know what, I am one smart cookie because I just *know* this patient has intussusception.” Let’s walk through your diagnostic workup and management in that case. The biggest deciding factor in doing anything here is asking yourself: is my patient stable or unstable? Stability (which includes hemodynamic and clinical stability) means you can proceed to diagnosis with the preferred imaging modality of ultrasound, whereas instability (such as hemodynamic compromise, signs of peritonitis, or altered mentation) would warrant more emergent mobilization of pediatric surgeons. While labs are unnecessary in intussusception, they may demonstrate a dropped hemoglobin, leukocytosis, acidosis, and electrolyte abnormalities if you happen to get them as a part of your differential.
With imaging, which you will always need for diagnosis, you have a few options at your disposal: an XR, ultrasound, or CT scan. The role of XR is limited in intussusception; you can obtain it if you have a low pretest probability, which would help rule out intussusception and highlight alternate diagnoses. The other time it is sensible to obtain an XR is when ultrasound is not available. Because of the relative lack of clarity with X-rays, an ultrasound remains the preferred imaging modality as it has reported sensitivities of 98-100% and specificities of 88-100%. It can show the target sign in a transverse view and a “pseudokidney” sign on the longitudinal view. Doppler can detect a paucity of blood flow to the target sign area, therefore increasing suspicion for bowel ischemia. Ultrasound is even useful in highlighting alternate diagnosis in a rapid, non-invasive way. Like everything, beware that an ultrasound has its limitations, like the fact that it is user-dependent. Occasionally, that opens up a role for CT. If you have a high index of suspicion and your other imaging modalities are inconclusive, a CT could show a segment of bowel invagination or suspicious edema focally in one bowel segment. Additionally, consider CT scans in older children outside the typical age range for intussusception; they are more likely to have lead points like polyps or intraluminal tumors that become more evident with cross-sectional imaging.
Now comes the fun part — let’s fix this. For every case of ultrasound-confirmed intussusception, you should consult a pediatric surgeon early on. They must be available to deal with any complications from reduction attempts. As always, make the patient NPO and start with isotonic IV fluids for resuscitation; radiologists feel a fluid-replete child will have a higher likelihood of successful reduction. Hydrostatically controlled contrast enema and air insufflation enemas have been successful for 70-95% of patients. Air contrast enema is the most common modality in practice currently. Care must be taken to avoid perforation, which could occur in up to 1% of patients, even in experienced hands. Reductions may fail for a number of reasons, but there are higher chances of failing if your patient is the following:
- exceptionally young ( < 3 months) or old ( > 5 yrs)
- if they have long duration of symptoms (> 2 days)
- Hematochezia
- severe dehydration
- Or evidence of small bowel obstruction.
There is some weak evidence that sedation may help achieve higher success rates, but this is not well-supported by current evidence and therefore your decision to use sedation will be based on your clinical judgment and institutional practices. You can confirm full reduction when you see proper reflux of contrast material back into the ileum. I want to note that reductions with enemas are out of bounds if your patient has signs of peritonitis on exam or imaging. Any degree of instability should prompt reduction in an operating room, and as early of a phone call to surgery as possible. Remember, the goal is to not delay reduction; we do not want gangrenous bowel.
If the first attempt at air contrast enema reduction is unsuccessful, your interventional radiologist will likely elect to attempt a second reduction in an hour. Continue to rehydrate with isotonic fluid and provide analgesia; IV acetaminophen is an excellent option here. There is no hard and fast rule, but most radiologists will stop after a third unsuccessful attempt. Regardless, the management at that point is laparoscopic or open reduction and bowel exploration. The children that fail three attempts are the ones that may have lead points that then warrant further investigation.
Now, can you discharge a well-appearing child after reduction straight from your emergency room? If you have observed them for 4-6 hours and if they tolerate oral intake, actually yes! But keep a few other factors at play in your decision. Ensure that the child has reliable caregivers and close proximity to an emergency department or a pediatrician’s office for outpatient follow up. Recurrence rates can occur in about 1 in 25 patients in the first 2 days, and, while low, warrant consideration.
That concludes the medical review of our topic, and we are nearly done, but another part of our job as pediatric emergency medicine providers is to stay current on the latest research about the topic at hand. I wanted to make a conscious effort to review that before we part. I’ll do that by discussing 3 recent studies.
- The first study is a recent meta analysis done on the utility of POCUS for intussusception. Between 11 retrospective and 3 prospective studies, they analyzed over 2000 children. Ultimately, as we mentioned before, the study ended up with very high sensitivity (94%) and specificity (96%) for the use of US in diagnosis. The variability in the sensitivity and specificity largely exists because the imaging modality itself is user-dependent. But the conclusion remains — continue using US widely for this diagnosis!
- Onto the second research study: Now that we live in a world with COVID, of course I couldn’t complete this podcast without somehow bringing it up! A small center study done in 2020 looked at 5 infants diagnosed with intussusception who also had COVID-19. Four did well and recovered while the fifth progressed to critical illness and eventual death. Given the very small sample size, it was unclear to the researchers if there exists a true correlation between COVID-19 and an increased risk of intussusception, and more studies need to be done to determine this. It does point to the notion that an infant who gets a diagnosis of intussusception should likely be swabbed for viral pathogens, including the novel coronavirus.
- Lastly, We touched on this lightly before, but let’s discuss literature on sedation practice in the context of intussusception reductions. A group recently looked into the use of sedation to improve reduction success in those who initially failed with traditional attempts. They found a success rate of 65% among patients requiring sedation after initial reduction failure. Those who continued to be unsuccessful despite the use of sedation ended up ultimately undergoing laparoscopic reduction without any further negative outcomes. No significant risk factors were found that led to failed reduction under sedation. While sedation is a popular consideration for children undergoing procedures, especially in the case of intussusception, a word of caution. Because this is a relatively understudied concept for treatment of intussusception, local practices, provider experiences, and interventional radiologist experiences should guide your decisions to use it , as discussed before.
Here are some pearls to review as we wrap up:
- Beware of the vomiting child in whom vomiting persists without evidence of diarrhea. While more of these children will declare themselves to have acute gastroenteritis, some truly do need to be evaluated for a process like intussusception.
- Intussusception has a classic “boards” triad of symptoms: colicky abdominal pain, palpable RUQ mass, and currant jelly stools. This is, in fact, only present in < 15% of patients, so be ready to act on the diagnostic pathway if this slam-dunk triad isn’t evident when they walk into your ED.
- Reduction maneuvers depend on hemodynamic and clinical stability. If they’re stable, you have the green light to attempt an air contrast enema, but be ready to mobilize your surgeons in the off chance you fail.
Thank you, everyone, for tuning into this review of a sentinel topic (and thank you to Dr. Sobolewski for letting me lead this episode). I know some of you had a hard time stomaching those puns, and I thank you for listening if you have somehow made it to the end. My gut feeling is that this may have been a fruitful discussion!
References
Shaw, K. N., Bachur, R. G., Chamberlain, J. M., Lavelle, J., Nagler, J., & Shook, J. E. (2021). Fleisher & Ludwig’s Textbook of Pediatric Emergency Medicine. Wolters Kluwer.
Dahan, N., & Francisco, B. (2021, November 3). Pediatric small talk – the rule of 6: Pediatric abdominal surgical emergencies. emDOCs.net – Emergency Medicine Education. Retrieved November 8, 2021, from http://www.emdocs.net/pediatric-small-talk-the-rule-of-6-pediatric-abdominal-surgical-emergencies/.
Sobolewski, B., PEM Blog Intussusception Part 2: Ultrasound-ing good. (2013, September 11). PEMBlog. Retrieved November 9, 2021, from https://pemcincinnati.com/blog/intussusception-2/
Sobolewski, B., Intussusception part 1: The basics. (2013, September 10). PEMBlog. Retrieved November 8, 2021, from https://pemcincinnati.com/blog/intussusception-1/.
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Ultrasonographic Diagnosis of Intussusception in Children: A Systematic Review and Meta-Analysis. J Ultrasound Med. 2021 Jun;40(6):1077-1084. doi: 10.1002/jum.15504. Epub 2020 Sep 16.
Doo JW, Kim SC. Sedative reduction method for children with intussusception. Medicine (Baltimore). 2020 Jan;99(5):e18956. doi: 10.1097/MD.0000000000018956. PMID: 32000420; PMCID: PMC7004751.
Centers for Disease Control and Prevention. (2018, July 25). Rotavirus vaccination. Centers for Disease Control and Prevention. Retrieved November 14, 2021, from https://www.cdc.gov/vaccines/vpd/rotavirus/index.html.
Centers for Disease Control and Prevention. (2011, April 22). Vaccines: VPD-VAC/rotavirus/Rotashield and intussusception historical info. Centers for Disease Control and Prevention. Retrieved November 14, 2021, from https://www.cdc.gov/vaccines/vpd-vac/rotavirus/vac-rotashield-historical.htm.
