Congenital diaphragmatic hernia- perils and pitfalls

   It may initially appear that Congenital diaphragmatic hernia or CDH is a simple straightforward diagnosis on ultrasound imaging. But is it? I have come across many cases where the sonologist can miss this diagnosis in late 2nd trimester or early 3rd trimester fetuses. The reason is because many small diaphragmatic defects may cause only partial or intermittent fetal diaphragmatic hernia. Thus the sonographer or sonologist may not see any herniation of bowel or stomach in left sided diaphragmatic hernias or right lobe of liver in right sided hernias.                                                                                                

   

The ultrasound video clip shows one typical case of left sided congenital diaphragmatic hernia (CDH), with classic midline shift of heart to the right, literally pushed to a corner in the wrong side of the chest. In this case the ultrasound diagnosis of CDH was made late into 34 weeks of gestation.This can be a disaster for the mother, who might not have wished to continue the pregnancy.
What are the differential diagnoses of left sided congenital diaphragmatic hernia?
Almost any cystic lesion occupying the left hemithorax can be confused with CDH in fetal ultrasound. Among these conditions are- cystic adenomatoid malformation, bronchogenic cysts and pulmonary sequestration. Also, not to be ignored are intrathoracic teratomas, as the cystic components of this tumor can mimic a CDH. Even more ominously, these lesions mentioned above can co-exist with CDH, making a diagnosis of CDH even more complicated.
You may want to read more at: http://www.ultrasound-images.com/fetal-chest.htm#Congenital_diaphragmatic_hernia-_Left_%28CDH%29
What is the prognosis in such cases?
The earlier the diagnosis of congenital defects in the diaphragm are observed on ultrasound, the worse is the prognosis for the fetus. In fact, the detection of congenital hernia in 2nd trimester means that the severity of the congenital anomaly is more severe. Most cases are also associated with other fetal anomalies, notably involving the fetal heart. Also, invariably, the pressure from the herniated bowel and stomach, in this case means there would be severe hypoplasia of the lungs. In fact, despite surgery in the neonatal period, many such babies have pulmonary hypertension and respiratory difficulties. Also present in many neonates is the danger of mental retardation, trisomy 18 and trisomy 21 as well as neural tube defects. The fetus in this case showed no other major anomaly, but the severe midline shift is evidence of a large hernia with resultant pulmonary hypoplasia.