Cincinnati Fetal Center

  • Congenital High Airway Obstruction Syndrome / CHAOS

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    What is CHAOS?

    Congenital High Airway Obstruction Syndrome / CHAOS is a condition in which the fetus has:

    • Massively enlarged lungs
    • A flattened diaphragm
    • A dilated tracheobronchial tree
    • Fluid in the abdomen
    • Other signs of in utero heart failure (non-immune hydrops) due to complete or nearly complete obstruction of the fetal airway

    What Causes CHAOS?

    The airway obstruction in Congenital High Airway Obstruction Syndrome / CHAOS may be due to:

    • The absence of or blockage of the larynx
    • The absence of or blockage of the trachea
    • A cyst which blocks the airway

    What is the Incidence of CHAOS?

    Congenital High Airway Obstruction Syndrome / CHAOS is a rare condition with fewer than 50 cases reported since 1989.

    How is CHAOS Diagnosed?

    Congenital High Airway Obstruction Syndrome / CHAOS is detected by ultrasound as a complete or nearly complete obstruction of the upper airway.

    The lungs appear extremely large. The diaphragm may be inverted and the heart compressed.

    The heart may appear elongated with its chambers compressed by the enlarged large lungs.

    The tracheobronchial tubes may be dilated and the fetus may have abnormal breathing movements.

    Although a fetus diagnosed with Congenital High Airway Obstruction Syndrome (associated with hydrops) is unlikely to survive without fetal intervention, in some cases the hydrops resolves and the fetus can survive.

    How is Pregnancy Managed with CHAOS?

    The mother should have a detailed ultrasound to detect associated abnormalities. A fetal echocardiogram will detect structural heart disease. A prenatal karyotype (the study of the chromosomes of cells) will confirm chromosomal abnormalities.

    The fetus should be followed closely for early signs of hydrops (in utero heart failure). The parents will want to consult with a medical geneticist and a pediatric surgeon to plan for delivery at a tertiary-care hospital that has expertise and experience in the EXIT (ex utero intrapartum treatment) procedure.

    What are Fetal Interventions for CHAOS?

    Fetal intervention for Congenital High Airway Obstruction Syndrome / CHAOS depends upon the gestational age at diagnosis and the presence or absence of hydrops. In rare cases, less than 30 weeks gestation, where it is known that the fetus is at significant risk for intrauterine death, open fetal surgery may be attempted. After 30 weeks gestation, an EXIT procedure may also be performed in order to obtain an airway at the time of delivery.


 
  • An illustration of CHAOS.

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    Congenital High Airway Obstruction Syndrome / CHAOS

    An illustration of CHAOS.
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    If you would like to request an appointment or get more information about the Cincinnati Fetal Center, call us at 1-888-338-2559 (1-888-FETAL59).