A diagnosis of a congenital diaphragmatic hernia is another one of those incredibly scary diagnosis that you never want to hear. Very often, babies with a CDH are severely, severely ill and it's not uncommon for there to be a poor prognosis associated with the diagnosis.
So what exactly is a congenital diaphragmatic hernia? It's an inborn developmental malformation of the diaphragm when the fetus is forming. Because the diaphragm does not close correctly between weeks 4-10 of development, it's unable to properly separate the chest cavity from the abdominal cavity and as such, the abdominal contents such as your intestines, liver, stomach, or spleen can theoretically herniate through the diaphragm defect and into the chest. Most often, the diaphragm defect occurs on the left side because the liver on the right side is somewhat protective.
Photo cred: The Lucina Foundation. Notice how the intestines herniate through on the left side of the baby into the chest cavity and thus pushes the heart towards the right side and prevents the lungs from expanding. |
What if you don't diagnose CDH on ultrasound? What if it's a late-onset CDH that doesn't appear until after the baby is born? What are some signs that can make you think of CDH? Some things I think about make a lot of sense when you think about the process of CDH - you might be able to hear bowel sounds in the chest cavity, you may also see a scaphoid or concave abdomen because of the decreased abdominal contents. The baby could also present with a number of respiratory or GI symptoms - signs such as grunting, flaring, retractions while breathing, or vomiting after eating. Most likely if there are any of these symptoms, you'll get a chest x-ray and you might notice a shift of the mediastinal structures (including your heart and your trachea) to the right side of the baby. Hopefully, you'll also see what could be intestines or other organs abnormally located in the left side of the chest. If it's still unclear by x-ray, you could always do a upper GI bowel study which allows contrast to run through the intestines and show up much more clearly.
Case courtesy of Dr Ahmad Thuaimer via radiopaedia.org. Arrows and circles drawn by me! The red circle around the entire left chest shows an intestinal gas pattern (red arrow) which indicates intestines that have herniated into the chest cavity. The yellow arrow points to the endotracheal tube after the baby was intubated. Although hard to see, the purple arrow points to the NG tube going down the esophagus and into the stomach. |
The prognosis of a baby diagnosed with CDH will vary depending on how severe the pulmonary hypoplasia is. The mortality rate can be over 50% if CDH is diagnosed prior to 25 weeks gestational age and it is very possible for babies to have to be on ECMO (Extracorporeal membrane oxygenation) for a long time. ECMO is a machine and technique that acts as the heart and lungs for the baby until the baby's own heart and lungs begin to work correctly to adequately exchange gasses. I have seen one patient on ECMO so far, and let me tell you, it is by far one of the most complex machines I have ever seen. It's really a miraculous piece of equipment and requires several intensivist Attendings to be watching over it and the patient.
Grabbed from google images - an ECMO set-up. Pretty intense right? |
I spent this post discussing Congenital Diaphragmatic Hernias because I had a patient who was diagnosed with it too. Luckily, hers was never detected on routine prenatal ultrasound and was a minor case of CDH. She was a trooper in the NICU and only had to be intubated for less than 48 hours after her surgery. I hope she's flourishing well now!!
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