Omphalocele

00:01 This talk is about Omphalocele and it may seem like omphalocele and gastroschisis are the same thing.

00:07 Not quite, they have a little bit different etiologies in terms of the developmental biology.

00:14 So omphaloceles are defects of the anterior abdominal wall.

00:17 This is at the base of the umbilicus.

00:19 And we'll see in a minute exactly why that happens.

00:23 As opposed to gastroschisis, the viscera in omphalocele is covered by the peritoneum, and by amniotic membranes, So it will look quite different, both grossly as well as by ultrasound.

00:36 So the epidemiology of omphalocele.

00:39 It has a slightly higher prevalence than gastroschisis about 1 in 5,000 births, and occurs for reasons that are obscure.

00:47 Boys more frequently than girls.

00:50 The maternal risk factors include very young age for a mom or much older moms.

00:58 And it can be part of syndromes associated with various chromosomal abnormalities.

01:04 The pathophysiology really has to do with the failure of the midgut to return to the abdominal cavity at 10 weeks gestation.

01:11 As we'll see, a lot of the bowel early on kind of protrudes into the yolk sac, and then develops in that location and then returns to the abdominal cavity.

01:22 If we don't do that appropriately, we don't get the abdominal folds to seal and it leaves a midline defect with bowel herniated out.

01:32 So here's our baby at 7 weeks of gestation.

01:35 And you can see going out into the umbilical cord region into the yolk sac region, we can see loops of bowel, that's completely normal.

01:45 However, by about 12 weeks, that's all returned back into the abdominal cavity.

01:51 And there will be some folding and other things that go on.

01:53 We'll talk about that when we talk about disorders of malrotation.

01:58 However, in the setting of omphalocele, we don't get that to return.

02:03 It stays outside.

02:05 And we have loops of bowel surrounded by a membrane that stick out of the midline right along where the umbilicus normally would be.

02:14 The clinical presentation.

02:16 You can see here at birth and herniation of intestines through an umbilical ring and it's completely surrounded by a membrane.

02:24 So that amniotic membrane and the peritoneum allow this to be somewhat protected.

02:29 So you don't have as much fluid loss or as much of a risk of infection as we would with gastroschisis.

02:37 The diagnosis and monitoring.

02:39 So ultrasonography is again, our best friend in trying to diagnose whether omphalocele is present.

02:45 In most cases, we pick that up very early on in pregnancy.

02:50 And it's part of the routine prenatal screening.

02:53 There may be other abnormalities.

02:55 And remember that there may be other genetic defects associated with this, so we want to be screening not just for omphalocele but for other possible abnormalities.

03:05 Again, shown here in ultrasonography, we have a big loop, several loops of bowel sitting outside of the abdominal cavity, and they do have a membrane around them.

03:15 So you can actually distinguish this from gastroschisis, just on the ultrasound.

03:22 Okay, so what do we do about omphalocele? Let's go to management and prognosis.

03:29 Because this loop of bowel outside of the abdomen can actually compromise respiratory excursion by limiting diaphragmatic movement, you may have or the baby may have lung hypoplasia.

03:42 And if this is unrecognized can lead to respiratory distress early on after delivery.

03:48 We have to be aware of that.

03:50 We also need to avoid just poking the thing back in and sewing it back up.

03:54 Those loops of bowel are prone to perforation.

03:57 So we have to be very careful and avoid just a simple manual reduction.

04:02 For small to medium size defects.

04:05 And there's normal lung activity: there's normal lung function, then the primary repair where we cut back the membrane and carefully reinsert the bowel back into the abdomen.

04:20 Close the defect, and we're good to go.

04:24 And with that, we conclude our discussion on omphalocele and gastroschisis developmental defects of the abdominal wall.