Congenital Pulmonary Airway Malformation

Congenital pulmonary airway malformation (CPAM) is a rare congenital birth defect that includes a cystic mass of abnormal lung tissue. A cystic mass is a noncancerous tumor that is filled with fluid or other material.

What causes this condition

In CPAM, the cystic mass cannot function as normal lung tissue. Males have this condition slightly more often than females. In most cases, CPAM is in only one of the lungs. (Less than 2 percent are in both lungs.) In 80 to 95 percent of cases, it is only present in one lobe of the affected lung. The right lung has three lobes, and the left lung has two lobes. CPAM can affect any of these lobes.

We do not know what causes CPAM. We do know that it is not related to anything the mother did or did not do during pregnancy. There is no reported incidence of this type of disorder recurring in a subsequent pregnancy.

CPAM is classified into three types:

  • Type I lesions account for 50 percent of the postnatal (after birth) cases. These are usually quite large cystic lesions that are few in number (1 to 4). This type has a very favorable outcome.
  • Type II lesions account for 40 percent of the postnatal cases. This type consists of more numerous smaller cysts. It is more commonly associated with other congenital anomalies, including those of the genital and urinary organs, cardiac and skeletal systems, as well as hydrocephalus and diaphragmatic hernia. The prognosis for type II depends upon the severity of the associated anomalies.
  • Type III lesions account for only 10 percent of the postnatal cases. These are usually large lesions that cause shifting of the organs that are normally found in the chest. This means that the windpipe, heart and unaffected lung are shifted and compressed. For this reason, the heart may not be able to function well. This can lead to the development of hydrops. Hydrops is an abnormal accumulation of fluid in at least two fetal cavities, such as in the abdomen, around the heart or lungs or under the skin. The prognosis for type III CPAM is poor, especially when hydrops occurs.

How this condition is treated

Congenital pulmonary airway malformation is often detected during a routine ultrasound during pregnancy. Additional tests can confirm the diagnosis, evaluate how severe the CPAM is, and identify any other problems. These tests include:

Magnetic resonance imaging to determine the size and location of the CPAM and see how the lesions are affecting lung development

Fetal echocardiogram to assess whether the lesions are affecting the baby’s heart structure and function

After the initial diagnosis, our team must monitor the baby’s and mother’s conditions closely throughout the pregnancy.

Fetuses with CPAM’s should be monitored closely during the pregnancy for possible heart failure. If fetal hydrops develops, the baby may be treated while in the womb using a variety of treatment options. In cases of Type I CPAM, thoracoamniotic shunting can be performed.

A thoracoamniotic shunt is a tube that is placed into the chest so that one end is in the cystic chest mass and the other end is protruding out of the chest and into the amniotic cavity. This tube allows for drainage of the cystic fluid within the CPAM into the amniotic fluid. By decompressing the CPAM, the lungs can develop more normally and the heart can function better.

After surgery

Treatment after surgery depends on a number of factors, including:

  • When the surgery is done
  • The size of the CPAM
  • How much lung was removed

If the CPAM involves both lungs or more than one lobe, your baby will have more limited breathing. If your baby has hydrops, unfortunately, he or she will likely have a much rockier course with a poorer prognosis. Some babies with hydrops will not survive to have surgery.

Breathing tube: After surgery, your baby will need continued help to breathe effectively. We will pass a special tube (endotracheal tube) through the vocal cords and into the windpipe. This tube helps with your baby's breathing, but it will also keep your baby from making sounds.

Blood draws: He or she will need frequent blood draws for lab work to monitor oxygenation, electrolytes, blood count and other things.

Medications: After surgery, your baby may need a variety of medications including:

  • Antibiotics to fight infection
  • Pain medication to control pain after surgery
  • Blood pressure medication to stabilize and maintain an adequate blood pressure
  • Sedation to keep your baby quiet so he or she does not become agitated
  • Paralytics to keep your baby from moving

IV lines: Your baby will have IV lines placed. The type of lines used will depend on the age at which the surgery is performed. If surgery is done soon after birth, the umbilical cord artery and vein will be used. Other IV lines can be placed in your baby's hands, arms, scalp, feet or lower legs. These are started just as they were for you while in labor.

Chest tube(s): Your baby also may have a chest tube on the side of the chest where the CPAM was removed. This helps the lung on that side re-expand into the chest space where the mass used to be. It will also drain any fluids that accumulate in the chest.

Urinary catheter: Your baby may have a urinary catheter passed into his or her bladder. This helps us keep an accurate assessment of how much urine the kidneys are making and allows us to test the urine to ensure your baby's well-being.

IV nourishment: Your baby will not be able to eat until his or her condition has stabilized, but we will continue to give nourishment through the IV fluids. Because babies with CPAM cannot eat for a while, special nourishment is given through the veins, typically through a central line or UVC. Total parenteral nutrition is an IV solution that contains protein, fats, sugar, vitamins and minerals. This will supply your baby with all his or her nutritional requirements until he or she is able to take food by mouth.