16. Fecal Diversions in Children - Indications and Management Due to Obstruction

In this class, we're going to begin our discussion of fecal diversions in children. Why are they done? What do you typically see? How do we manage them? In this class, we're going to do an overview and then we're going to focus specifically on conditions causing bowel obstruction. We'll talk about common reasons for fecal diversions in children, big picture. We'll talk about normal fetal development of the GI tract, and then we'll talk specifically about developmental failures that result in obstructive congenital defects. So the first thing to know, because you think, oh my gosh, a baby, a child, having to have an ostomy. So the first thing you want to know, fecal diversions in children are very uncommon. And secondly, if we do have to do a fecal diversion, almost always it's temporary. So it's very uncommon to see a permanent ostomy in a child. Now common reasons include congenital conditions causing obstruction, acute inflammatory conditions that could result in perforation, and finally inflammatory bowel disease. So just in follow up to what we just said, if you look at the two big categories of pathologic conditions that might result in fecal diversion in a child, most of them fall into the obstructive category, so intestinal atricias, ovulus, Hirschbrung's disease, or maconiumilus. And then there's a smaller group that fall into the category of inflammatory processes, necrotizing intercollitis, and neonates, and inflammatory bowel disease, typically in school age or adolescents. So we can back up and talk a little bit about normal development of the GI tract during fecal development. So during the fifth to eighth week, the bowel is enlarging so rapidly that there's not really room for it in the abdominal cavity. So it actually leaves the abdominal cavity, extends into the umbilical cord, and then during the tenth to twelfth week, there's enough room in the abdominal cavity. So the bowel rotates 270 degrees, retorns to the abdominal cavity, and becomes fixed in place. And if all of that occurs normally, the ascending colon will be on the right side, transverse colon, of course, across the midline, and descending and sigmoid on the left. Now things can go wrong. If there is a failure of abdominal wall closure, you can end up with a baby with gastrochesis or umphalaseal. If there's a failure of rotation or a fixation, you can get abnormally mobile sections of the bowel that can result in either intermittent or complete volulose. So we're going to talk about each of those and what the implications are. We're going to start with gastrochesis. So with gastrochesis, what you have is herniation of loops of bowel through the abdominal wall defect. So here, the abdominal wall failed to close normally. The bowel herniates through that open defect. With gastrochesis, there is no amniotic covering. So the exposed bowel is short, thick, and a dimptus. And you can see in the illustration on top that bowel doesn't look remotely normal. Now gastrochesis is more common among premature infants. Most of them, this is an isolated defect. Usually a small percentage have other defects that might result in mortality. So overall, among infants with gastrochesis, mortality is typically 15 to 30%. The vast majority, this is an isolated defect, it's correctable, and the baby is going to recover and be fine. And though it looks terrifying at the outset, and certainly to the parents, it's overwhelming and terrifying. How is this ever going to be okay? So how do we make it okay? How do we correct this? Well treatment typically involves silo. And silo means that you place those loops of bowel in a sterile plastic bag and you elevate the bag above the level of the abdomen so that a dimma gradually resolves. And once those loops of bowel become normal, so the dimma's been eliminated, then you can take the baby to surgery, you can return those loops of bowel to the abdominal cavity, and do at least partial closure of the abdominal wall. Women is rarely required, so these babies do not typically end up with an osteomy. If wound osteomy nurses are consulted, it's typically for wound care, for management of that abdominal wall defect. What about on fallacyl? What's the difference in gastrochesis and on fallacyl? Well again, you have persistence of that abdominal wall defect, the abdominal wall failed to close normally, and abdominal organs like the bowel herniate through that umbilical ring and the abdominal wall defect. But here, the loops of bowel are covered with the amniotic membrane, so the structures are protected, they're catmoist. The bowel is typically normal, you have minimal if any dimma of the loops of the bowel. So at the outset, looking at the bowel issue, it's like, oh well, um fallacyl sounds better than gastrochesis, but unfortunately, 60% of infants with fallacyl have other major defects, and because of those other major defects, mortality rates are pretty high, usually 70 to 80%. Now management's very much like gastrochesis, except you don't have to wait for the loops of bowel to subside and diameter, a dimma's not an issue, so operative repair is done as soon as possible after birth. Again, if we are involved, it's usually for wound care, because diversion is typically not required. Now, a fairly common cause of obstruction along the intestinal tract in an neonate are intestinal atretias, and atretia means loss of continuity. It's thought to be the result of a vascular accident in utero, and atretias can actually occur anywhere along the intestinal tract all the way from the esophagus through the colon. Now you can get variable severity. It can range from stenosis, like you see on the bottom left where you have an acute narrowing that makes it very difficult for anything to pass through, but it also can be a complete separation, which is what you see on the bottom right, where there's complete separation of the two ends of the bowel and the mesentery. Atretias, by far, the most common cause of obstruction in the neonatal population. The one good thing about atretias is that they're typically diagnosed very promptly, frequently diagnosed even before birth, if not, they're diagnosed soon after birth, because the obstruction causes feeding intolerance. So quickly identified so that intervention can be initiated. There's no way to fix an atretia, except to remove that section of bowel and do an end-to-endanastomosis. Now I want you to look at the illustration on top. When you look at the section of bowel just distal to the stomach, that looks like the abnormal section because it's very dilated, but actually that dilutation is the result of the atretia, which is just distal to that section. So if you look carefully, you'll see that just distal to the dilated area is an area that's acutely stenotic. So when you have an atretia, either a total separation of the two ends of the bowel or stenosis, then nothing's going through, everything proximal to that point dilates. So when they go in surgery, they don't go in surgery. What they have to do is they have to take out the acutely dilated segment and then they have to connect the two good ends. Most of the time, a treatise is involved a relatively small section of bowel, so typically you can remove the dilated section, connect the two good ends, and you have minimal, if any residual pathology. Normally, bowel function is, okay, once you remove the dilated section and restore continuity. But what if you had a fairly distal atreasure, what if there was a little bit of delay in the diagnosis, and what if you had a very large section of bowel that was very dilated and had to be removed. Remember that you need at least 100 centimeters of functional small bowel to prevent TPN dependence, to prevent short bowel syndrome. So the surgeon is always very aware of that, okay, how much do we need to preserve? Most of the time, not an issue. They're able to remove the dilated section, to do an end indenestimosis, restore intestinal continuity, restore normal bowel function, we don't get involved. The exception is esophageal atreasure. So I want you to look at the illustration of the med portion of your slide and to the far left. So if you have esophageal atreasure, now you have either a stenosed or totally discontinuous area of the esophagus. And most of the time, they're not going to be able to pull the two functional ends of the esophagus together. There's not enough tissue and not enough mobility. So many times they require a temporary esophageostomy. Where they go in there, they connect the proximal end of the esophagus to the neck. And then saliva drains out through that opening. Anything the baby drinks goes out through that opening. So that esophageostomy does need to be pouched. Once the baby is big enough and stable enough, they will come back and do esophageal reconstruction typically. They use a section of colon. They pull it up to reconstruct the esophagus. In the meantime, our role involves the management of this esophageostomy, also known as a spit fistula. So esophageal atreasure does involve an esophageostomy and we will be involved in care of that infant. Okay, so moving on from esophageal or small balatricias, on the other end, you can have anorectal malformations, also known as imperfect anus. Now this is relatively uncommon. It occurs in about 1 out of 5,000 live birds. So uncommon, but not rare. It's more common in boys. 50% of infants within perforated anus have some kind of associated defect. So there's a group of defects known as the bacterial syndrome where you have vertebral, anal, cardiac, tracheal, esophageal, renal, and limb anomaly. So if you have a baby with a bacterial syndrome, there's a lot going on. You can see the parents would be totally overwhelmed. They would need a lot of support. Looking specifically at anorectal malformations, they are classified as either low defects or high defects. And that classification has significant implications in terms of management and in terms of prognosis for continents. You'd much rather see a baby with a low defect. What does that mean? A low defect means that most of the anorectal complex formed. So you have formation of the recto-signoid. Typically you have formation of most of the anal canal. The sphinters are intact. So if you look at the slide on bottom or the illustration on bottom, you can see in orange that yes, the recto-signoid did form normally, and the anal canal and sphinters are intact. In contrast, with a high defect, the bowel terminates above the pelvic floor sling, above the puborectalis muscle. The anal sphincter is typically missing. And the prognosis for continents is much poorer in infants with high defects. We'll go through that in more detail. So if you have a low defect, typically as we said, the anal canal has formed, sphincters are intact. But either you have an anal opening that's covered over by skin, so there's no visible anus on inspection. Or the anal opening is displaced. It's not lined up correctly. It doesn't line up with the anal canal. So one of the things they always do right after birth is they always assess visually for the anal opening and they'll do a rectal tint to see, okay, is their patent anal canal. If there is a low anal rectal malformation, it's pretty simple to correct. If there's misalignment or if there's coverage with skin, they can just remove that covering skin and they can align the anal canal with the anal opening. So it's a minor procedure. Long term prognosis is excellent because the sphincters intact. So long term, you really don't expect this baby to have any problems. That can, you can be very reassuring and talking with appearance. High anal rectal malformations are much more significant. So here, and I want you to look first at the illustration on top. And you can see that either the recto sigmoid ends in a blind pouch or as you see in the illustration on top, it communicates either with the vagina and girls or with a bladder or urethra and boys. So here you see it communicating with the proximal urethra in a male infant. So this is essentially anal rectal atreasia. There is failure of the anal canal to form failure of the anus to form. So now it's like, okay, well how do we fix this? Well, goal number one is to eliminate the bowel obstruction to restore fecal elimination. So first they'll do a diverting colostomy. That's the first thing. Once we do a diverting colostomy, now the baby can still normally through the stoma. We can feed the baby and we can plan for reconstructive surgery. Now the reconstructive procedure that is typically done is known as the pinia procedure because Dr. Pinia is the surgeon who developed this. It's also technically known as a posterior sagittal anal rectoplasty. It's like what? So what does that mean? That means they're going to do a pull through procedure. So they have to mobilize the proximal bowel disconnected from the vagina or from the urethra or the bladder. Mobilize it. Pull that proximal bowel through the pelvic floor muscle sling because you won't support for continents as much support for continents as you can get. So they can actually identify the site on the pelvic floor where you have the strongest collection of muscle fibers, the greatest resistance. And then they pull the bowel through that area and create an anal opening. So if you look at the illustration on bottom, you can see in purple where they have mobilized the bowel, brought it through the pelvic muscle sling created an anal opening. And then once that heals they can close the colostomy and then still will pass all the way through through that created an anal opening. Now they create a narrow opening because we do want to support continents long term and typically parents have to be taught to dilate the anal canal to prevent stenosis and obstruction. Long term continents may be an issue that's down the road that we may have to really work intensively with that child to establish bowel continents. The next Next condition that can cause an obstruction is volvulus. We've talked about this in previous classes because volvulus can actually occur in infants and children and in adults. What you have is an abnormally mobile section of bowel that is prone to twisting. It can twist around the mesenteri to cause what they denote as a closed loop obstruction. Now volvulus can be partial and intermittent, which is not nearly as bad as if it's acute and complete. If it's partial and intermittent, you get a partial twist which causes partial obstruction, distinction, cramping pain, possibly nausea and vomiting, but then it resolves. When volvulus is intermittent, you can get delay and diagnosis. Once they figure out what's going on, they will resect that abnormally mobile section of intestine, doing int and denestimosis to prevent recurrence. When it's acute and complete, when you get a full twist that cuts off blood flow and also causes an acute obstruction, they get rapid development of ischemia. They're very high risk for perforation. The only good thing you can say is that the clinical picture is so extreme with rapid development of distinctions, severe pain, the baby's crying nonstop. It's vomiting that they get to surgery almost immediately, so there's rapid recognition that something is acutely wrong, baby gets taken to surgery and the condition is corrected. Now what are they going to do? Ideally, they get the baby to surgery before the bowel perforates, they're able to resect the involved bowel, doing int and denestimosis, no ostomy is required. But if by the time they get to surgery, there's already some degree of perforation and leakage, or if there's extensive ischemic disease and they're afraid to put the bowel back together, then they'll remove the involved section, the obstructed segment, and they'll typically bring both ends out to the abdominal wall as a functional clostomy and a distal mucus fistula. Maconium Ilius is not common at all, you may never see an infant with maconium Ilius, but I'm going to briefly go through this so you know what it is. In case you do encounter a child with maconium Ilius either in your clinical practice or on the certification exam either could happen. So what is it? It's actually not in Ilius, it's an intestinal blockage, and it's caused by dried maconium. So you get these dry gray pellets of stool that accumulate in the distal Ilium in the acin in colon, and they block transit through the bowel so they cause a blockage. Why would you get this? This typically seen in infants with cystic fibrosis, and you know that cystic fibrosis involves a genetic mutation that alters transport sodium chloride and water. It affects primarily the pulmonary system and the GI system does have effects on the reproductive system as well, but within the GI tract it causes drying and emancipation of the maconium. So how do these babies present? They're blocked, so they're going to have abdominal distinction, they're going to have vomiting, feeding intolerance. Again, they're going to be diagnosed quickly because of the feeding intolerance. One of the classic findings in terms of diagnostic studies is this ground glass appearance due to the mixture of maconium and air in the distal Ilium in acin in colon. Okay, how do we manage them? Typically medically. So they'll put down a nasogastric or oral gastric tube just to decompress the proximal bowel, relieve a lot of the discomfort, start to resolve some of the abdominal distension. Obviously the baby is going to require IV fluids because right now they can't tolerate oral intake and we have to maintain hydration, hydration is critical to resolving this issue, and antibiotics because they're at risk for perforation. And then typically they'll do hyper-osmolar, hyper-osmolar, enemas and irrigation using mucomis because you know mucomis is a surfactant, it pulls water in and breaks up thick secretions in the pulmonary system, can do the same thing in the gastric and intestinal system. So if we instill mucomis solution through a nasogastric tube it's going to get down to the distal small bowel, it's going to pull water in and have a surfactant effect on those meconium pellets, start to break them up. If there's a lot of dried meconium in the acin in colon, then they can feed a catheter in through the rectum and the distal colon and give a hyper-osmolar enema to start to break out the meconium in the acin in colon. If they can break up that obstructing meconium then they can restore bowel patency and normal function. So surgery is a last resort, it's done only if the meconium ilias is complicated by perforation by infection or if medical management fails. Sometimes they can just go in and do it in erotomy, make a little opening into the bowel wall and instill the hyper-osmolar solution irrigate all that meconium out and then close the defect. Very occasionally they'll have to resect the area bowel with all the unspecated meconium and do a proximal diversion and distal mucus fissula which gives them access for repeated irrigations as well as temporary fecal drainage. And then once the problems resolved they close the osteomy. Now children with cystic fibrosis are also at risk throughout life for distal, let me see if I can say this distal intestinal obstructive syndrome, D I O S. So this can occur in older children with cystic fibrosis because again they have this very thick mucus, they can get very thick stool especially if they're borderline on fluid intake. Treatment would be exactly the same, unfortunately we don't see much of that at all. Probably the most common cause of obstruction other than atrasias is Hirschwung's disease. It is Hirschwung's disease. It actually is congenital absence of the ganglion cells in the bowel wall and of course the ganglion cells control parasitic activity, control intestinal motility. If you have a muscle and it's no longer innovative that muscle does nothing, it just sits there. So essentially it causes denervation of variable links of the colon. So you end up with a functional obstruction and I want you to look at the illustration on bottom. So you have massive dilatation of the descending colon and at first glance you think that's where the problem is. You see that very distended section of bowel, no, the affected segment is the recto-signoid. So look at the recto-signoid on that illustration is collapsed and it has caused massive dilatation of the descending colon. The descending colon is innervated, it's essentially normal and trying to compensate for that obstructed segment of bowel. Now one thing you need to know about Hirschwung's, this goes back to neonatal development is that innervation of the bowel proceeds from distal, I mean from proximal to distal. So if you've got a little theory handing out ganglion cells, it's going to start proximally and proceed distally. So the first portion of the colon to be innervated is the ascending colon. That's the transverse, next the descending, finally the sigmoid the rectum. So if anything interferes with this process, which section is going to be involved? If there's any interference at all, if the rectum would be the first to lose out on an innervation, the sigmoid would be next, then the descending, then the transverse, then the acinding. So that tells you, in an infant with Hirschman's disease, the rectum and the internal anal sphincter are always involved. And then there's variable links of colon involved as well, depending on how extensive the disease process is. So short segment disease means you're dealing with the innervation of the rectus sigmoid. Long segment disease involves varying links of the colon. You can get total colonic aganglianosis, but that is rare. And you can very occasionally get total intestinal aganglianosis, but that's extremely rare. You are very unlikely to see that. So short segments, by far the most common, let's talk more about that. So you've got congenital absence of ganglion cells that affects the internal anal sphincter and the rectum and may involve part of the sigmoid colon. What happens is the denervated segment of bowel collapses because nothing's going through there. And then the proximal bowel distance massively because it's trying to push things through, trying to push stool through that section that is not working and is collapsed. Now the problem with short segment, Hirschbrung's disease is that sometimes diagnosis is delayed because initially that proximal bowel is typically able to at least partially compensate, push some stool through. So many times the child is diagnosed with severe constipation. Diagnosis usually occurs when this becomes a persistent problem. So my baby is always constipated and it's always severe. And then they do an x-ray and they find a transitional zone of narrowings. So what do we mean by that? Well if you look at the illustration on top, you can see that the segment of bowel between the very dilated descending colon and the recto sigmoid, it looks kind of like a funnel. That's the transitional zone of narrowing between the proximal innervated bowel and the distal denervated bowel. And then if you have an infant with persistent severe constipation, you do a flat plate x-ray and you see this transitional zone of narrowing, now they're going to do a recto biopsy. And they're looking to see are there ganglion cells in the recto wall? Recto biopsy is considered the gold standard in terms of diagnosis. Okay so then how do they manage infants with short segment, Hirschbrung's disease? Hirschbrung's involving the recto sigmoid. They're going to start with a proximal colostomy. They have to divert the fecal stream in order to decompress that very very dilated section of bowel. So typically the ostomy is done within that proximal dilated section and that means that the stoma is very large. So here you have an infant, you would expect a very small stoma and instead what do you get? This very large stoma because the bowel is so distended, so dilated. I have had to leave the pediatric hospital, go over to the adult hospital to get a pouch that was big enough to accommodate the ostomy. So it would be critical to prepare the parents to say this is going to be huge at first. Now it's going to shrink down, it's going to end up ever so much smaller than it is now but I just want you to try to prepare yourself for what it's going to look like initially. Okay so first of all you restore bowel function, you restore stool elimination and you start to decompress that very dilated section of bowel by doing a temporary colostomy. Then you're going to resect the aganglionic section of bowel, the non-functional section of bowel and you're going to enastomose the functional segment to the very distal rectum right above the anal canal. And there are several different surgical approaches. It's the Swinson, Duamel and Suave procedure and if you end up in pediatrics and you're dealing with a lot of these children, yes you need to know those but if not you just need to know that they bypass or remove that aganglionic bowel and connect the functional, innervated bowel right above the anal canal. Then once everything heals they close the colostomy. Now right after closure of the colostomy frequent stooling is very common so you have to protect the perianal skin with moisture barrier products. You have connected the bowel right at the anal rectal junction, you're going to get scar tissue that could cause stricter so many times the parents have to be taught dilation of the anastomotic line to prevent stricter. We will work with the parents to assure that the infant and the child is getting enough fiber to produce soft form stool because we're already trying to set this child up for continents down the road. We know that there are things you're going to have to overcome. The internal anal sphincter is never going to be innervated so it's not going to respond normally. Normally rectal distinction prompts relaxation of the internal sphincter. No, you're not going to get that. The internal sphincter is going to be closed so the child is going to have to learn to use Valsalva to override the internal sphincter and to push stool into and through the anal canal. We need to tell the parents up front it may take longer to toilet train this child because the proximal or the internal sphincter does not work normally. What about long segment harshbrunks? This is where most are all of the colon is egg anglionic. The one good thing is this will be diagnosed promptly because the baby is going to have feeding intolerance. He's not he or she will not pass meconium and will have will not tolerate feats is going to be distended and vomiting. So most of the time they get diagnosed within days of birth that means that the bowel has not yet had a chance to dilate so typically they can do surgical intervention and one procedure. They can remove the egg atlionic section of bowel, connect ganglionic to just above the anal canal. Now one thing you need to know about harshbrunks disease or potential long term complications there's two of them that we want you to know about interoclytus and incontinence. Now interoclytus is just what it says an infection involving the small bowel or the large bowel. You would think that the infant would only be at risk for interoclytus when they had that very dilated section of bowel that once surgery had been done that that risk would be gone but that's not true. They can actually develop interoclytus prior to or following surgical management for reasons I don't understand I've never read a good explanation for that but it's consistently documented so that's what you need to know. What are the signs and symptoms of interoclytus? Typically they're running fever they're very lethargic they have foul smelling dark green or gray stool it can be explosive they're bellies distended so they look sick and they're having foul smelling diarrhea. So we tell parents if your child looks sick and has diarrhea don't delay don't waited out, bring hell man, bring her in, we'd much It's rather fine that, oh, it was just a viral gastroenteritis, then miss an infectious diarrhea. So, your baby looks sick and they're having diarrhea, bring them in. The other complication is incontinence. Remember that the internal anal sphincture is not innervated, will not behave normally. To try to prevent long-term complications, we want to make sure that the anal rectal junction does not become stenotic or structured so it may be very important to teach the parents those deletations and to help them understand how important it is. Adequate fiber intake, balance in fiber and fluid, establishing self-form stool will be essential. We're going to have to teach this young child to bear down and to use that bearing down maneuver to push stool through because their internal sphincture does not open. So, in summary, fecal diversions in children are very uncommon. If they have to be done, they're almost always temporary. Most of them are due to congenital conditions causing obstruction. Atresia is the most common of strutative condition, does not typically result in anostomy unless it occurs at the level of the esophagus or at the level of the distal colon and rectum, which is also known as an anorectal malformation or imperferent anus. Volvulus involves a twisting of the bowel when it's abnormally mobile. Maconium Ilius involves dried and spissaded maconium that causes a functional obstruction typically in children with cystic fibrosis and Hirschbring disease involves absence of ganglion cells and a section of denervated bowel. Most of those will require surgical intervention, some of them will require at least a temporary ostomy. Thank you.