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Let's talk about necrotizing and enteritis.

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This is a big problem because it is a very common

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abnormality in very low birth weight, infants

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and premature infants.

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And despite improved outcomes in, uh, patients cared

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for in the neonatal ICU for all other indications,

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unfortunately this is still common in NICUs

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with a high mortality rate.

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So up to 40% mortality rate in infants who are diagnosed

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with necrotizing an colitis.

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Not to mention increased length of stay in the hospital

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and other associated abnormalities as a result

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of a necrotizing enteritis diagnosis.

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Depending who you ask, the etiology

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of necrotizing enterocolitis is multifactorial.

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It is controversial. Everybody agrees.

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Necrotizing inter colitis follows a pretty, uh,

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well delineated disease course in that you have, um,

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altered biodiversity of the microbes in the bowel.

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You have some sort of cellular injury

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that allows the bacteria to invade the bowel wall

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and that can lead to intestinal necrosis.

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And depending on the severity, sepsis

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and a systemic inflammatory response

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and bacteria being able to invade into the um,

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intestinal wall is why we see pneumatosis intestinalis in

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the setting of necrotizing enterocolitis.

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More to come on that, um, later.

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Unfortunately, the clinical presentation can be, uh,

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confusing in infants for neonatology, uh, colleagues

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'cause it can be variable.

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Um, presentation. The most common is abdominal distension

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with bloody stools.

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They might have a sepsis like picture the infant with um,

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temperature and blood pressure variability

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or just feeding intolerance.

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Um, neck can involve any c can involve

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any part of the bowel.

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It's kind of like Crohn's disease in that any part

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of the bowel can be impacted by necrotizing inter colitis.

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Our job is to distinguish

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between medical necrotizing in colitis,

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which can just be treated by stopping feeds parenteral, um,

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feedings and then uh, empiric IV antibiotic um, therapy

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and distinguishing between surgical ne,

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which is any evidence of perforation of bowel

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'cause that those are surgical, that loop

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of bowel needs to go be resected.

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Um, these patients can be quite sick with um,

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profound sepsis and vital sign instability.

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Again, the treatment of medical neck

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and surgical neck NEC is the shortened version

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of necrotizing enterocolitis.

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Um, the treatment is different, which is why our job is

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to distinguish between medical NEC

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and surgical NEC so

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that the clinical colleagues can appropriately triage

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and care for these patients.

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The purpose of imaging

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besides distinguishing between um, medical neck

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and surgical neck is to, number one, confirm the diagnosis

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and then, um, identify any complications.

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So anything that might lead the surgeons to, um,

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go into the patient's belly to resect a loop bowel

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or take a look to look at the viability of bowel.

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You'll hear different schools of thoughts on the role

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of radiographs versus ultrasound in the setting of concern

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of necrotizing enteritis.

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And I think they are complimentary.

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I think we have both of the tools at our disposal

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and so we should use both of those tools to help diagnose

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and, um, triage these patients.

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So on x-rays, we're looking for gas, not only intraluminal,

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intramural portal venous,

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and then within the peritoneal cavity itself,

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but we're also looking for evidence of in utero

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or prior, um, perforation as it relates to calcification.

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So meconium, peritonitis, ultrasound,

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we're looking at different things typically.

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So number one, we can see fluid at ultrasound much better

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than we can see at x-rays.

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Obviously not only within the lumen of the bowel loop,

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but the wall of the bowel, any fluid within the wall, um,

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or any focal fluid or fluid collections

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or complex fluid in the peritoneal cavity.

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When we're looking at the bowel wall,

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we wanna look at the thickness

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or thinness, um, the, uh, perfusion of that bowel

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and we also wanna look for peristalsis.

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Um, so in a patient who is intubated

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and sedated, you can have decreased peristalsis

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as a result of sedation.

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We wanna make sure that there isn't just like one focal area

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of bowel that is peristalsis different from

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all the other loops of bowel.

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And then of course we can see gas at ultrasound as well,

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not only within the lumen, within the wall,

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within the portal venous system

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and then also within the peritoneum.

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We can diagnose pneumoperitoneum at ultrasound as well.

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Um, so I always, uh, have colleagues

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who are concerned about, oh,

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would you call this pneumatosis?

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Would you call this pneumatosis at ultrasound?

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And they hem and they haw.

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But don't forget, it's not just pneumatosis

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hashtag's, not just pneumatosis.

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If you're an X fan at ultrasound, we know we can diagnose,

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uh, abnormalities related

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to necrotizing enteritis earlier than at x-ray.

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Number one bowel thickening.

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We can see, um, earlier than on x-ray at ultrasound.

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Um, we can see doppler flow either hyper uh, flow

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or hypo flow at Doppler.

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Um, ultrasound we can look for peristalsis in addition

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to pneumatosis portal venous gas.

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Don't forget about the mesentary.

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Patients with um, necrotizing enteritis will have, um,

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mesenteric thickening.

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They can also have abdominal wall thickening.

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So this patient with anasarca here.

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And then anytime you see complex fluid in a patient

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with necrotizing enteritis, that is perforation

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until proven otherwise.

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So this abnormal academic ascites is, um, diagnostic

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of bowel perforation in a patient with NEC.

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I love this paper from monocle albumin showing the

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progression of necrotizing enteritis over

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time at ultrasound.

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So normal bowel wall is normal in thickness,

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it's normal in perfusion.

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The first thing that happens with necrotizing enteritis is

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you get bowel thickening

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and hyperemia as the disease progresses.

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You have continued bowel wall thickening,

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but you start to have decreased perfusion of

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that thick walled bowel.

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Then you have thin walled bowel

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and uh, finally the end stage right immediately prior

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to perforation is vascular and thin walled bowel.

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So we wanna definitely catch patients

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before they get to this end stage appearance at ultrasound.

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So what about this patient?

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Should we go on to ultrasound in this patient?

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And I would argue absolutely not.

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Number one, this is unequivocal pneumatosis intestinalis.

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So check out this peripheral aspect of this loop

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of bowel in the right mid and lower abdomen.

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Once you see straight lines of lucency start lining up,

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that's pneumatosis intestinalis.

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Not only that, but check out this branching lucid tree-like

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structure projecting over the entirety of the liver,

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including projecting over the left hepatic globe.

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This is portal venous gas.

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So in this case, we don't need to recommend ultrasound.

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We don't need to do ultrasound.

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They can treat this patient as necrotizing in colitis.

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Of course, if there's a question of perforation,

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we can do a cross table lateral

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or uh, a left lateral decubitus

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radiograph to look for perforation.

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Um, but just based on this image, this looks like medical

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NEC and they can treat this patient without

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having to do additional imaging.

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What about this patient? So, um, don't get distracted

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by the right upper or Lois.

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There's an endotracheal tube, there's an enteric tube,

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there's an umbilical venous catheter,

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and yes, this patient has lung disease of prematurity.

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There is a super important finding in the

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abdomen of this infant.

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We have this continuous diaphragm sign

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and then we have this huge subtle

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but huge abnormal lucency in the central upper

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aspect of the abdomen.

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They're the arrows. To help point that out to you.

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This is pneumoperitoneum.

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So this patient has, um, intestinal perforation.

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We don't need to go to ultrasound.

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Um, in order to help diagnose this perforation,

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this patient can just be, um, surgically managed.

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Um, as the next step, um, expeditiously

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of course we wanna confirm that it's a true finding.

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So you can do a cross table lateral view

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or a left lateral decubitus view.

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This pa this image on the right is actually our patient.

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This image on the left is a different patient

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where you can see this pneumatosis intestinal

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is much, much prettier.

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These are just other examples of an infants with necrotizing

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and tra colitis where you see pneumatosis intestinalis

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and portal venous gas.

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So don't forget to look

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for portal venous gas anytime you're questioning whether

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or not, um, some like, uh, lucencies are lining up

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that make you concerned for NAC.

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Okay, so let's go over another example where, um,

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ultrasound might be useful.

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Um, as opposed to those other cases

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where the diagnosis was pretty clear on x-ray.

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So this was a 30 day old,

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former 31 week gestational agent Ben, who had hydrops fatals

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and increasing abdominal distension.

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This patient had an abdominal catheter placed

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to help manage their ascites related to their hydrops.

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Um, this bowel gas pattern isn't exactly normal,

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but I don't see anything that's like a slam dunk.

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Like yes, this is definitely pneumatosis intestinalis.

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I don't really see portal venous gas.

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And then on this decubitus view,

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I certainly don't see any pneumoperitoneum. So we

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Went to ultrasound for this patient to help

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with problem solving because clinically they were super

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concerned about necrotizing enteritis,

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but the two of you abdomen x-ray wasn't super helpful.

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So on the ultrasound, um, we immediately saw a ton

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of portal venous gas.

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So this, um, cinematic images showing you the two different

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types of portal venous gas to look out for.

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Number one, we can see this mobile, um,

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air in the main portal vein.

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The portal vein itself is hard to see,

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but this gas moving here is portal venous gas.

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And then number two, this is the fruit pulp appearance

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of portal venous gas on ultrasound.

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So it's like diffuse portal venous gas within

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the parenchyma itself.

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So not only within the parenchyma,

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but we see frank portal venous gas in this

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patient's main portal vein.

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So this is portal venous gas on ultrasound.

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When we imaged uh, this patient's abdomen,

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we did see pneumatosis

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and this is what this, this is what, uh,

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necrotizing in colitis

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with pneumatosis intestinalis looks like.

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So number one, our abdominal wall is abnormal.

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We have this reticular edema tracking

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through the thick wall, the anterior, um,

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abdominal wall fat.

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So that's one thing to look for in addition

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to this pneumatosis intestinalis.

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So when I'm looking for pneumatosis intestinalis on an

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ultrasound, I don't just look at the non-dependent aspect

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of the loop of bowel.

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I need to see, uh, gas within the dependent

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or uh, posterior aspect of the bowel wall as well so

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that I don't over call the mitosis.

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So look, not only for the anterior aspect

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but also the dependent aspect of the loop of bowel

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to help you diagnose pneumatosis intestinal is.

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And this is uh, uh, still showing you that exactly

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that this is gas within the wall of the loop

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of bowel anteriorly posteriorly.

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And then here is that abdominal wall thickening

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and reticular edema.

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Now importantly, this patient later on

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did develop obvious radiographic findings

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of not only pneumatosis intestinalis,

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but we could see the portal venous gas clear

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as day on the x-ray.

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So, um, we saw the manifestations earlier on ultrasound than

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we did on radiographs in this patient.

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So ultrasound can be super helpful for problem solving.

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This was another example

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where ultrasound was particularly helpful.

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This was a three week old, extremely premature infant

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who we imaged for an indication of line placement.

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And I'm pres, I'm presuming that it was the pick that, uh,

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was the, the line in question

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and that looks like it's projecting over the lower in

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hepatic IVC, but this patient's bowel gas

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pattern is abnormal.

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So, um, we talked about the inner particular distance being

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the normal, um, caliber of a single loop of bowel.

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And this loop of bowel is definitely two dilated number one.

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Number two on follow-up imaging, this loop

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of bowel persisted.

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So we have, uh, this is one day before

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and this is the following morning.

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This is what we call a fixed loop of bowel.

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So not only is it dilated, it is stuck in the same location.

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The other thing is this bowel gas pattern doesn't have

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that normal mosaic tile appearance of bowel loops.

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This has a featureless appearance of bowel loops.

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So it looks like each of these bowel loops is like a tube

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of toothpaste that has been um, sort

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of like squirted into the abdomen.

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And this tube of toothpaste in particular looked the same

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one day prior as it did um, the following day.

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So we have featureless, tubular dilated bowel loops.

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So this is concerning for NEC.

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I didn't talk about this pneumatic cell

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and this patient's left, left lower lung zone.

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This was a pneumatic cell. And yes,

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this patient definitely has lung disease of prematurity.

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Just to follow up back on the rest

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of the abnormalities on these, on these two x-rays.

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So this patient went to ultrasound

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and this is one of my favorite cases of all time

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because it helps me to demonstrate, um, some

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of the important findings of necrotizing and tra colitis.

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Number one, the,

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we have what's called a peritoneal stripe sign.

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So we have some thick walled sort of zebra looking bowel.

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I'm gonna stop this ine um, at the end

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of this sine we have thick walled bowel.

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It looks like tiger stripes or zebra stripes.

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So this is a thick wall loop of small bowel.

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Number two, when we look at between the bowel loops,

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we have this academic material that is genic fluid that is

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between these loops of bowel.

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So we have increased space between our bowel loops

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with genic material.

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And last but not least, I'm gonna highlight this

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pneumoperitoneum, which is at the beginning

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of this cinematic image.

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So this is called the peritoneal stripe sign.

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Um, so we have this bright line

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with these posterior reverbing echoes.

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And if you don't believe this cene,

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come look at this following still image.

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So this is our peritoneal stripe sign

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where we have gas in the peritoneal cavity

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that gases all the way up against the, um,

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anterior abdominal wall.

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And contrast that with this loop of bowel here.

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So this is bowel gas within a lumen of a loop of bowel.

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So you see that this gas is not stuck all the way up against

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the ventral, um, inner wall of the abdomen.

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This is within a bowel loop and this is pneumoperitoneum.

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So this is the peritoneal stripe sign.

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So this is pneumoperitoneum at ultrasound near the arrow.

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So the white arrow is showing you pneumoperitoneum

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with reverb posteriorly.

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This is just, um, b vest within a loop of valve.

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And this is this patient four hours later on this

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cross table lateral view.

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It was like obvious pneumoperitoneum.

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Um, so from surgical NEC in this, in this infant, um,

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where ultrasound was helpful

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for making the diagnosis earlier.