About CDH

What is a congenital diaphragmatic hernia (CDH)?

A diaphragmatic hernia is a birth defect (an abnormality that occurs before birth) that develops as a fetus is forming in the mother's uterus. A congenital diaphragmatic hernia (CDH) occurs when the diaphragm does not form properly. The diaphragm is a thin sheet of muscle that separates the abdomen from the chest. The diaphragm is an important muscle for breathing. When there is an opening in the diaphragm, organs that are normally in the abdomen can be pushed (herniated) through the opening into the chest. Currently little is known about why this birth defect occurs.

What causes a diaphragmatic hernia?

As the fetus grows in its mother's uterus before birth, different organ systems are developing and maturing. The diaphragm forms between the 7th and 10th week of pregnancy. The esophagus (the tube that leads from the throat to the stomach), the stomach, and the intestines are also developing at this time.

In CDH, the diaphragm does not develop properly and some or all parts of the abdominal organs (stomach, spleen, intestine and/or liver) move into the chest. The displacement of these abdominal organs into the chest can affect how the lungs develop and grow.

Most cases of diaphragmatic hernia are believed to be multi-factorial in origin. Multi-factorial means that many factors, both genetic and environmental, are involved. It is thought that multiple genes from both parents, as well as a number of environmental factors that scientists do not yet fully understand, contribute to the development of a diaphragmatic hernia.

Approximately 40% of cases of CDH are associated with other birth defects. The most common is a congenital heart defect.

Up to 20% of cases of CDH have a genetic cause due to a chromosome defect or genetic syndrome. In many of these cases, the child has other birth defects in addition to the CDH.

How often does a diaphragmatic hernia occur?

CDH occurs in about 1 in 2,000 - 1 in 5,000 live births.

Who is at risk for developing a diaphragmatic hernia?

All pregnancies have a 2-3% risk for some type of birth defect. One type of birth defect is a CDH.

Parents who have had one child with an isolated CDH, meaning no problems other than the CDH, are at increased risk to have another child with the same problem. For most families this chance is approximately 1-2% or 1 in 100 to 2 in 100.

If there is a known cause for the CDH, the recurrence risk depends on the specific diagnosis.

Why is a diaphragmatic hernia of concern?

The lungs develop at the same time as the diaphragm and the digestive system. When a diaphragmatic hernia occurs, the abdominal organs move into and develop in the chest instead of remaining in the abdomen. With the heart, lungs, and abdominal organs all taking up space in the chest, the lungs do not have space to develop properly. This may cause the lungs to be small and underdeveloped.

A diaphragmatic hernia is a life-threatening condition. When the lungs do not develop properly during pregnancy, it can be difficult for the baby to breathe after birth. The baby may be unable to take in enough oxygen to stay healthy.

Not only can there be problems with the lungs from this abnormal development, but there can also be problems with the digestive system as well as the heart.

What are the symptoms of a diaphragmatic hernia?

The symptoms of a diaphragmatic hernia are often noticeable soon after the baby is born. The following are the most common symptoms of a diaphragmatic hernia. However, each child may experience symptoms differently. Symptoms may include the following:

• difficulty breathing
• fast breathing
• fast heart rate
• cyanosis (blue color of the skin due to low oxygen levels)
• abnormal chest development, with one side being larger than the other
• abdomen that appears caved in (concave)

The symptoms of diaphragmatic hernia may resemble other conditions or medical problems that affect how a baby breathes. Always consult your baby's physician for a diagnosis.

How is a diaphragmatic hernia diagnosed?

Many babies with CDH are identified before birth by ultrasounds performed during pregnancy. The ultrasound provides pictures of the baby’s organs and allows the doctors to see whether the abdominal organs are in the right position. The ultrasound also allows doctors to check the position of the heart and lungs of the developing baby. In some cases, the CDH is not diagnosed until after the baby is born. Babies with CDH will have difficulty breathing right after birth. As a result, a chest x-ray is done to evaluate the lungs. The chest x-ray in infants with CDH allows the doctors and nurses to see that parts of the stomach, intestine, and/or liver are in the chest area.

Ultrasound image of a L CDH: This is a cross sectional view of the fetus. The fetus is positioned on the side and the head is located off screen to the right. The stomach (st) is visible in the left portion of the chest and the heart (hrt) is deviated to the right.

Neonate with a prenatally diagnosed L CDH pre surgery. Click on an image to see a larger version with labels.

 

After birth, your baby's physician will perform a physical examination. A chest x-ray is done to look at the abnormalities of the lungs, diaphragm, and intestine. A blood test known as an arterial blood gas is often performed to evaluate the baby's breathing ability. The baby’s vital signs (heart rate, blood pressure, oxygen saturation, and respiratory rate) are followed very closely. The baby may also have an echocardiogram (an ultrasound of the heart) and a blood test blood for genetic analysis.

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How is a diaphragmatic hernia treated?

Neonate after thoracoscopic repair of R CDH. Click on the image to see a larger version with labels.

All infants with a congenital diaphragmatic hernia will need to be cared for in the Neonatal Intensive Care Unit (NICU). Specific treatment will be determined by your baby's physician based on the following:

• your baby's overall health and medical history
• the severity of the problem and the degree of breathing difficulty
• your baby's tolerance for specific medications, procedures, or therapies
• your opinion or preference

 

Treatment may include:

Mechanical Ventilation

A diaphragmatic hernia is a life-threatening illness. Most affected babies are unable to breathe well enough on their own because their lungs are underdeveloped and/or prevented from expanding by the abdominal organs in the chest area. Most babies will need to be placed on a breathing machine called a mechanical ventilator to help their breathing. In addition, a suction catheter is placed into the baby’s stomach, from the nose or mouth, in order to remove any fluid or air that fills up the stomach in order to prevent further pressure on the lungs.

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ECMO (Extra Corporeal Membrane Oxygenation)

Some infants with severe breathing problems may need to be placed on a temporary heart/lung bypass machine called ECMO. ECMO does the job that the heart and lungs would be doing: putting oxygen in the bloodstream and pumping blood to the body. ECMO may be used temporarily while a baby's condition stabilizes and improves.

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Neonate with prenatally diagnosed L CDH post surgery

Surgery

When the baby's breathing condition has improved, the diaphragmatic hernia will be repaired with an operation. The stomach, intestine, and other abdominal organs are moved from the chest cavity back into the abdominal cavity. The hole in the diaphragm is closed.

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Many babies will need to remain in the NICU for a while after surgery. Although the abdominal organs are now in the right place, the lungs may remain underdeveloped. The baby will usually need to have breathing support for a period of time after the operation. As your baby’s lungs continue to recover and your baby needs less help from the breathing machine, the ventilator is removed and your baby does all of the work of breathing. However, in very severe cases, where the lungs may be immature because of the CDH, your baby may still need breathing support, oxygen and/or medications to help with breathing for weeks, months, or years.

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Can there be problems in the future?

Babies born with CDH may have minimal to no problems after they leave the hospital, or they may continue to have lung problems and other medical concerns even after they leave the NICU. For these reasons, babies born with CDH often need regular follow-up care by different specialists after going home from the hospital.

Some babies may continue to have lung disease, which may require breathing support, oxygen, and/or medications to help their breathing for weeks, months, or even years.

As a result of the stomach and/or intestines developing in the chest, many babies with CDH will have gastro-esophageal reflux disease (GERD). The GERD may affect the baby’s feeding. In GERD, acid and fluids from the stomach move up into the esophagus (the tube that leads from the throat to the stomach) and can cause heartburn, vomiting, feeding problems, or lung problems. Gastro-esophageal reflux can often be controlled with medications prescribed by your child's physician.

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Some babies will have difficulty growing and gaining weight. This is known as failure to thrive. The children with the most serious lung problems are most likely to have growing problems. Because of their illness, they often require more calories than usual in order to grow and be healthy. Gastroesophageal reflux can also cause feeding problems, preventing a baby from eating enough to grow and gain weight.

Some babies can have developmental problems. They may not roll over, sit, crawl, stand, speak or walk at the same time as other babies do. Physical therapy, speech therapy, and occupational therapy are often helpful for these babies to gain muscle strength and coordination.

No two babies born with CDH are exactly alike. Your baby’s doctors and nurses will discuss your baby’s condition and treatment plan with you and tailor it according to your baby’s medical and surgical needs. In addition, how each baby recovers and the problems babies may face as they grow and mature will also be different. Again, your baby’s doctors will tailor treatment and care plans according to the needs of your child.