A CPAM baby is one diagnosed with Congenital Pulmonary Airway Malformation (CPAM), a rare, non-hereditary condition involving the abnormal development of lung tissue before birth. This malformation results in a lesion, often a cyst or a mass, usually located in one lobe of one lung. While the diagnosis may sound alarming, the majority of cases have an excellent prognosis, with many lesions shrinking during pregnancy. The cause is unknown and is not linked to maternal actions.
Understanding the Malformation
CPAM is characterized by an overgrowth of the terminal respiratory bronchioles, forming a mass of abnormal tissue that does not function like normal air sacs. This lesion can be solid or contain fluid-filled cysts, typically affecting only a single lobe of the lung. Composed of abnormal lung structures, the tissue cannot participate in oxygen exchange.
The condition is classified into different types based on the size and composition of the cysts within the lesion. Macrocystic lesions (Type I) contain one or more large cysts measuring greater than two centimeters in diameter. Microcystic lesions (Type III) appear more solid on imaging because they consist of numerous, very small cysts less than 0.5 centimeters. Mixed lesions (Type II) contain a combination of both large and small cysts.
The size and type of the malformation are significant factors in determining severity. Larger masses can compress surrounding healthy lung tissue and shift the heart. This compression can impede the growth of the remaining healthy lung tissue, a condition called pulmonary hypoplasia. The cause is thought to be an error in lung development very early in the pregnancy, around eight to nine weeks of gestation.
Detecting and Monitoring CPAM During Pregnancy
CPAM is most often detected during a routine prenatal ultrasound, usually performed in the second trimester. The ultrasound may show an area in the fetal chest that is unusually bright, indicating the presence of the abnormal mass. Once a lesion is identified, further diagnostic tests, such as Fetal Magnetic Resonance Imaging (MRI), are used to confirm the diagnosis and define the lesion’s location and structure.
The primary tool for monitoring the lesion’s growth and predicting risk is the CPAM Volume Ratio (CVR). The CVR is calculated by dividing the estimated volume of the CPAM mass by the fetal head circumference, which normalizes the lesion size for gestational age. This ratio helps medical teams monitor whether the lesion is growing disproportionately to the fetus, which would suggest a higher risk.
A CVR value greater than 1.6 is considered a high-risk indicator for the development of hydrops fetalis. Hydrops fetalis is a severe complication characterized by excessive fluid accumulation in the baby’s body, caused by the mass compressing the heart and major blood vessels. Lesions with a CVR below 1.6 are low-risk, but all CPAMs require close follow-up with serial ultrasounds during pregnancy.
Management and Treatment Options
For the majority of CPAM cases, the lesion remains small or regresses before birth, meaning the only management required during pregnancy is close monitoring. This expectant management involves regular ultrasound scans to track the CVR and watch for complications like hydrops. Delivery is typically planned at a specialized center with a Neonatal Intensive Care Unit (NICU) to ensure immediate access to specialists.
In the rare instance that a high-risk lesion develops hydrops, fetal intervention may be considered to improve the prognosis. For microcystic lesions causing hydrops, maternal administration of steroids (betamethasone) can sometimes slow the growth of the mass and reverse fluid accumulation. For macrocystic lesions with a dominant cyst, a thoracoamniotic shunt may be placed—a small tube inserted to drain fluid from the cyst into the amniotic fluid.
The standard treatment for a CPAM after birth is surgical resection, involving removal of the affected lung lobe (lobectomy). If the baby is born with severe respiratory distress, emergency surgery may be performed within the first few days. For infants who are asymptomatic at birth, elective surgery is typically scheduled between two and six months of age to prevent complications like recurrent infections or malignant transformation.
Life After CPAM: Recovery and Long-Term Health
The long-term outlook for children who have had a CPAM removed is excellent, with most living normal, active lives. Removing a single lung lobe rarely results in permanent breathing difficulties because the remaining healthy lung tissue compensates and grows to fill the vacant space. This compensatory growth allows for good pulmonary function as the child gets older.
Recovery following surgery usually involves a short stay in the NICU for monitoring, often lasting only a few days if a minimally invasive approach is used. Post-operative follow-up ensures the child is recovering well and monitors for complications. This care often includes routine chest imaging (X-ray or CT scan) to confirm complete resolution and proper lung expansion.
A small number of children may have minor, non-clinically significant reductions in lung function, but these usually do not restrict physical activity. Parents can be reassured that the intervention is curative; the vast majority of children with an isolated CPAM who undergo successful resection have the same lifespan and quality of life as their peers.