CDH Overview

CDH results from a hole formed in the hernia during development, potentially leading to migration of bowel contents into the chest cavity. Original image (User Theresa knott [CC BY-SA 2.5 (https://creativecommons.org/licenses/by-sa/2.5)])

What is Congenital Diaphragmatic Hernia (CDH)?

To understand CDH is to first understand the diaphragm. This skeletal muscle forms the boundary between the heart and lungs and the abdominal cavity. Contraction of the diaphragm drives respiration. In CDH, a hole forms in the diaphragm during development. Depending on hole size (severity), this can sometimes allow contents of the abdominal cavity to migrate into the chest.

With abdominal contents in the chest, the lungs can become obstructed. This sometimes results in pulmonary hypoplasia (underdeveloped lungs), pulmonary hypertension, developmental delays, and additional health challenges after birth. More severe forms of CDH can be fatal. Hernial defects can occur anywhere within the diaphragm, but usually occur on the patient’s left side. It is unclear why this is the case.

How is CDH diagnosed and managed?

Typically, CDH involves three major defects: i) diaphragmatic defect, resulting in failure to close, ii) migration of abdominal contents into the chest cavity, and iii) lung hypoplasia.

Diagnosis of CDH can be before or after birth of the baby. Sometimes, defects are quite apparent by ultrasound. Milder cases can require a skilled sonographer to detect the hole (hernia), or a fetal MRI. Typically, healthcare professionals leery of CDH will use these tools to identify underdeveloped lungs, ectopic location of organs (such as bowels in the chest or displaced heart), and liver position to aid in diagnoses (see below).

Head, right; feet, left; thorax (chest), center. In this ultrasound of CDH, the stomach and heart can both be seen within the thorax. (Dr Laughlin Dawes [CC BY 3.0 (https://creativecommons.org/licenses/by/3.0)])

Depending on severity, CDH can be managed prenatally or postnatally, but often both. Prenatal interventions most often involve close monitoring, and some cases may require surgery. Most of the time, babies with prenatally diagnosed CDH will undergo vaginal birth. For more severe cases, mother may be transferred to a hospital where delivery can take place near a center with ample support. This can include Extracorporeal Membrane Oxygenation (ECMO), wherein the heart and lungs are bypassed until the baby can breathe autonomously.

Proper precautions and care for babies born with CDH requires a team of qualified healthcare professionals.