Episode Transcript
Interviewer: Congenital diaphragmatic hernia, what is it? What causes it and what can you do about it? We'll cover the basics of this terrible birth defect next on The Scope.
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Interviewer: Congenital diaphragmatic hernia, also known as CDH. You might not have ever heard of it but it's likely more common than you thought. It's estimated about 1 in 3,000 children are born with it, which puts it with diseases you've heard about like spina bifida, which is one in 1,000 or even cystic fibrosis, which is about the same, one in every 3,000. Dr. Stephen Jay Fenton, the pediatric surgeon is also an expert in congenital diaphragmatic hernia. Thanks for taking time to talk about this somewhat unknown disease. Is that a fair assessment?
CDH Life Expectancy
Dr. Fenton: It's obviously well known to us. We take care of it often but I think maybe some of it is secondary to the survivability. I mean it isn't something where kids will live as long as some of the kids with cystic fibrosis. So there are not as many families out there that are dealing with these types of kids. There is about 40 percent to 50 percent mortality rate associated right off the bat with congenital diaphragmatic hernia.
So now the children that survive, most of them will go on and live normal lives as a kid but it's something that's dealt with in the neonatal period primarily and not later on in life and so that might bring a little less notoriety to it.
As far as cystic fibrosis there's a lot more kids although it's one in 3,000. There are a lot more kids with cystic fibrosis kind of walking around out there. Some of it may be who is the champion for it, whether there's celebrities that are champions for cystic fibrosis or whatnot. I mean I think that might play a part as well.
What Is CDH?
Interviewer: Yeah. So a pregnant woman is told her baby as CDH. What does that mean for the child?
Dr. Fenton: First of all, we should just kind of talk about what it is which is basically a hole in the diaphragm. And the diaphragm is the muscle between the abdomen and the chest. And what happens is this hole develops early in the development of the child and causes bowel or solid organs to herniate up into the chest.
When it does this it arrests the lung in an earlier stage of development. And so what ultimately happens is not a matter of the intestines or liver, let's say, being up into the chest but it's actually result of very hypoplastic or underdeveloped lungs as well as thickened pulmonary arteries. And that's really the big consequence of a CDH.
Interviewer: I see. It's not a physical hole you see though in the stomach. It's all internal, right?
Dr. Fenton: It's all internal. Yeah, you would never see it on the child. The only thing you really see on the child is that their belly looks really, really flat and it looks much flatter than normal because some of their abdominal contents were up in the chest.
Interviewer: So if I'm understanding correctly what happens is because of this membrane is not there, the organs move up and is that what stunts the growth of the lungs?
Dr. Fenton: Exactly.
Interviewer: There's just no space for them to grow.
Dr. Fenton: That's exactly right.
Interviewer: Is this something that can be detected before the woman gives birth?
Dr. Fenton: Oh, yes. Yeah. The great majority of these are detected prenatally, during the screening ultrasound let's say. So ultrasound is very good at detecting the herniation.
Interviewer: So give me an idea of the degrees then. How many children are born and it's not super serious. It's something that can be... or is it always super serious?
Dr. Fenton: Yeah. Very, very rarely. Every now and then I would say we get a child maybe one or two, every couple of years that come in and are great. Most kids though come in with a pretty big defect and because of the size of the defect they have very underdeveloped lungs and have something called pulmonary hypertension which is also a consequence of the underdevelopment of the lungs and they're sick.
They require ventilatory support so they need to be on a ventilator. They require medications sometimes to help with their blood pressure and how well their heart is working. And they also require medications to try and help open up the pulmonary arteries in order to reduce what we call pulmonary hypertension which is really something that we did as challenge immediately after birth.
CDH Repair in Infants
Interviewer: As a surgeon then, what do you do to try to solve this problem?
Dr. Fenton: Well, the surgery is a major step but it's not the first step as far as these are concerned. Once the kids are born, the key is really to stabilize them from a medical standpoint. So we want to try and help them breath, but we want to do it in a way that won't cause long term damage to the lungs. So we want to kind of do this gentle ventilation if possible and sometimes that can be very difficult because they require quite a bit of support.
We also want to make sure that we're supporting them from a cardiac standpoint. So we need to make sure that their heart is working well, that their blood pressure is normal. And then we need to work them up for any further anomalies. And then once they've stabilized their pulmonary hypertension is under control, we feel like they've been stable for at least 24 hours then we repair them. And this does require surgery, so we do make an incision in the abdomen and we go in and we go find the hole and there's really kind of three options that we can do to fix it.
So one is the hole really isn't that big and we're able to bring the two edges together without tension. When we can do that, then we just close it what we say primarily. But most of the time the holes are bigger than that and we can't close it without tension. So in that case we can either put a synthetic patch in, something that has called it a dual mesh. It has cortex on it so it protects the lung on one side and kind of allows tissue to grow into it on the other side. And that will allow us to close the hole without tension.
One of the things that we do here at Primary's is what we call a muscle flap. The abdominal is made of three muscles to the side and we actually take the internal-most muscle and rotate it inward and sew it in. So it's what we call a biologic fix, meaning that it's actually part of the baby that is helping repair the hole. And we like that because we found that it reduces the risk of it coming back. So reduces the risk of recurrence and then it also grows with the child.
Surgery Recovery
Interviewer: Okay. So after the repair is done, the organs are back where they belong. What's the recovery process at that point?
Dr. Fenton: So it's still quite a bit. Now I usually tell parents they should plan on their child being in the hospital for three to four months.
Interviewer: Will the lungs ever fully develop properly?
Dr. Fenton: Yeah. Well the lungs actually continue to grow until the child is around eight years of age. So with support, and if we've been able to use gentle techniques to the point where the lungs aren't damaged, then they should be able to grow to the point where the child can live a pretty normal life. Now some of them are so severe that they will have some pulmonary consequences later on in life. They might still require some oxygen. They might not be able to exert themselves as much without being tired.
Now I think something that is important is that these kids are kids that should be followed for a long period of time. So they will still have some consequences of pulmonary hypertension. So it's not a child that after their repair and after they leave the hospital, we don't see. They're actually children that are still followed by specialists.
Interviewer: Do you have any thoughts for parents or families that found out that this is a birth defect that's in their family?
Dr. Fenton: I guess the biggest thing to say is that they can be well supported. Even though it's not known commonly throughout the community, it is something that we treat very often at Primary Children's Hospital. There are a lot of specialists that deal with this not just from the surgical standpoint but from the lung standpoint, from the neonatal standpoint, etcetera. And they can come and see these specialists and get the support, that information that they need that will help them not only through the difficult time prenatally but also through the time immediately after birth and then throughout the child.
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