Congenital Diaphragmatic Hernia
Congenital Diaphragmatic Hernia (CDH) is a serious abnormality that could occur in the baby whereby the ‘skin’ separating the chest and the abdomen (diaphragm) is defective with a hole. Thus, the abdominal organs can pass through this hole of the diaphragm and stay in the chest. The heart and lungs that are normally in the chest would then be compressed.
How common is CDH?
CDH isn’t very common as it happens in one out of 2000 to 5000 deliveries. 80 to 90 per cent of the CDH happens in the left side, while 10 per cent occurs in the right side and less than five per cent in both right and left sides.
Why is CDH serious?
It is commonly associated with chromosomal abnormalities (abnormalities in the genetic make-up), for instance, Down Syndrome, Edwards Syndrome, Patau Syndrome. It is also strongly associated with other abnormalities of the baby’s organs. More than 50 per cent would have at least one other abnormality. Nervous system is the commonest organ involved (30 per cent involvement), followed by the heart (20 per cent association). Other organs that could be involved are kidneys, spine and limbs.
How could CDH be detected?
If there is no routine Foetal Anomaly Scan (FA Scan) performed, the majority is detected incidentally. It is found by chance when something not quite right is noted or when the water around the baby (amniotic fluid) is too much. Then, a Foetal Anomaly Scan may be ordered by the obstetrician. In many unfortunate cases, it is only diagnosed after the baby is born and found to be having breathing difficulty. In the FA Scan, a CDH baby would have the stomach in the chest rather than the normal abdominal position. The bowels may also be in the chest with the heart pushed to the right side. The lungs will be smaller in size due to the compression from the abdominal organs invading their space.
What are the chances of survival of a baby with CDH?
The survival is 65 per cent if the CDH is the only abnormality in the baby. The chance of survival is very low if chromosomal aberrations are present. For example, Patau Syndrome and Edwards Syndrome themselves are lethal. Down Syndrome itself does not have a very good prognosis.
The prognosis is worsened if:
- There are associated chromosomal problems or structural abnormalities.
- The baby’s liver is involved. Liver involvement would lead to 57 per cent of such babies to demise whereas only five per cent death if no liver involvement.
- It happens before 24 weeks of pregnancy because the longer the heart and the lungs being compressed, the less likely they would develop normally.
- Large CDH
- Right CDH or CDH involving both sides.
- Excessive amniotic fluid volume (polyhydramnios).
In the extreme when the whole baby is swollen with fluid accumulation in the chest, around the heart and also in the skin layer.
What should be done if the baby is diagnosed with CDH?
Once CDH is suspected, a detailed FA Scan should be performed to fully assess the entire baby. First, it is to confirm the diagnosis. Secondly, it is to confirm whether any other abnormalities are also present. Thirdly, it is to check the well-being of the baby whether there is an abnormal fluid accumulation in the baby’s body, and the amniotic fluid volume. Next, either an amniocentesis (to take amniotic fluid) or a foetal blood sampling should be done to rule out chromosomal abnormality. If the chromosomes are normal, depending on the extent of the abnormality present, the baby should be monitored closely.
Where should the baby with CDH be delivered?
The baby should be delivered in a well-equipped hospital so that the best care could be given to the baby as soon as he or she is born. Once the baby is stabilised, an operation would be needed to correct the position of the abdominal organs as well as to repair the defect of the diaphragm.