Children's Hospital Colorado
Colorado Fetal Care Center

Pleural Effusion (Hydrothorax) and Congenital Chylothorax

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What is pleural effusion in children?

Pleural effusion, also called hydrothorax, refers to fluid collecting around the lungs. This can occur before or after birth. When this occurs to a baby still in the womb, we call it congenital (present at birth) pleural effusion. There are many causes for congenital pleural effusion, including:

  • Anemia (low red blood cell count)
  • Cardiac anomalies
  • Chest masses
  • Chromosome and genetic abnormalities
  • Congenital chylothorax
  • Infections

What is congenital chylothorax?

Congenital chylothorax is the most common cause of congenital pleural effusions and occurs in 1 in every 15,000 pregnancies. Chylothorax can cause fluid buildup on one side of the chest or both sides, compressing one or both lungs while the baby is still inside the womb.

What causes chylothorax?

Congenital chylothorax comes from the thoracic duct not fully developing in the womb, or a blockage of the thoracic duct, which drains lymph from inside the chest. Lymph is a fluid containing white blood cells, which attack and break down things like bacteria, viruses and damaged cells.

Who gets congenital chylothorax?

It’s hard to predict who will get congenital chylothorax, but the condition appears to affect males twice as much as females.

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