What is a CPAM?

A CPAM is an abnormal area of tissue on the lung that is present from birth. They happen when tissues in the lungs or airways haven’t developed properly during pregnancy. What causes them isn’t known.

CPAM are the most common type of congenital lung abnormality. Most babies with CPAM can be delivered normally and will not have any obvious symptoms after they are born. CPAM are usually detected before your baby is born, at the 20-week prenatal scan. They often get larger during the last trimester of pregnancy, before shrinking again before birth.

There are different types of CPAM. A single CPAM can be ‘hybrid’, meaning having multiple different tissues in it. Doctors will not know for certain exactly which type of CPAM your baby is affected by unless the decision is to remove it by an operation after birth.

At some time after birth (timing will vary between different hospitals), your child will have a scan to find out more about the CPAM. A chest CT scan with an injection of dye will show the abnormality. A type of dye called contrast is injected to help the blood vessels show up on the scan. The injection will only last a few seconds, and the scan itself is painless.

Different types of CPAM that may show up on a chest CT scan include:

• bronchogenic cysts: this is when pockets of tissue called cysts develop on the bronchial tree (the system of airways called bronchi and bronchioles)
• bronchial atresia (absent bronchus): this is when one or more airways at the very end of the bronchial tree (peripheral bronchi) are missing and the airway beyond the blockage swells by ongoing production of lung fluid
• bronchopulmonary sequestration: this is when a mass of abnormal lung tissue develops next to the lung, or inside one lung. It’s usually solid rather than air filled and doesn’t function or connect with the rest of the breathing system
• congenital cystic adenomatous malformation (CCAM): this is when pockets of tissue called cysts develop in one or more sections (lobes) of the lung
• congenital lobar overinflation (CLO): this is when one of the lobes of the lung gets overinflated. This squashes and moves the lung tissues next to it and causes breathing difficulties. It’s sometimes known as congenital lobar emphysema (CLE) or congenital large hyperlucent lobe (CLHL).
• foregut duplication cyst: this is when during pregnancy, some parts of the unborn baby’s lung develop abnormally. At first, in the very early stages of development, the lung bud (which goes on to form the lungs) grows out of what will become the gut. This means that some lung cystic abnormalities look like parts of the intestine when removed and examined under a microscope.

What are the symptoms of a CPAM?

Most babies with CPAM have no obvious signs of chest problems.

Some babies with other congenital lung abnormalities will have breathing problems as soon as they are born. Symptoms can include:

• noisy breathing, known as stridor
• a blue colour on your skin, lips, tongue, or gums (cyanosis).

Sometimes a baby may have significant breathing difficulties and may need help with their breathing. This might include ventilation (a breathing machine) or taking oxygen through a face mask or tubes in their nose.

What are the symptoms in older children and adults?

Most children with CPAM will not experience symptoms.

In older children and adults, symptoms of congenital lung abnormalities can include:

• infections that keep coming back in the affected area of the lung
• bronchiectasis
• asthma-like symptoms (coughing, wheezing, breathlessness) that do not respond to asthma treatment.

How are CPAMs treated?

Babies and children with CPAM and other congenital lung abnormalities will usually go to specialist centres to investigate and manage their condition. If the abnormality is found on an antenatal scan, the pregnancy will be monitored, and arrangements may be made to deliver the baby in a specialist centre.

Treatment after birth

Treatment for CPAM after your child is born will depend on their condition and if they have symptoms.

A few babies with congenital lung abnormalities may need emergency surgery when they are born. Others may have an operation because of features shown on a CT scan or following any complications that may develop after they’re born.

If your child has symptoms, the CPAM should be removed surgically.

As your child grows up, if they do not have any symptoms, they may not need immediate treatment and will have regular check-ups to monitor their condition.

Some children may be offered surgery before any symptoms show to remove the CPAM. This may be to try and reduce infections that keep coming back. You should be involved in making the decision with the health care professional. Policies on surgery before any symptoms show differ between treatment centres, and there is not enough evidence to help decide which CPAMs are at risk of complications. You should ask your paediatrician to explain the risks and benefits of surgery.

Other than surgery, your child will need treatment for any complications that happen related to their congenital lung abnormality. For example, they’ll need antibiotics if there is an infection in the affected area. However, once a CPAM gets infected, it likely needs to be removed surgically to stop repeat infections.

Long-term outlook and complications of CPAM

Some people live with congenital lung abnormalities for a long time without having any symptoms at all. Their condition might be discovered by chance when they have a chest X-ray (or especially in adults, a CT scan) for a different reason.

The long-term outlook and any long-term complications for CPAM and other congenital lung abnormalities will depend on the type of condition your child has. Generally, when CPAM is diagnosed prenatally (before your child is born), the long-term outlook is good. However, a few types of CPAM (around 5%) can develop complications and it is not known which.