Congenital high airway obstruction syndrome: prenatal ultrasound diagnosis and literature review

Congenital high airway obstruction syndrome (CHAOS) is a rare congenital anomaly involving the upper airways (trachea, larynx). It is a life-threatening condition whose true incidence is unknown. The obstruction may be due to tracheal/laryngeal atresia, stenosis, or the presence of a mass lesion. Prognosis is poor, generally resulting in stillbirth or intrauterine fetal demise. Ex utero intrapartum treatment (EXIT) is possible if the condition is detected early. We present a case of CHAOS diagnosed during a second-trimester anomaly scan with postmortem confirmation and literature review.