CHAOS With Multiple Fetal Craniospinal Anomalies: A Case Report

Abstract

Congenital high airway obstruction syndrome (CHAOS) is a rare and lethal anomaly with 100% mortality, if not diagnosed in utero and perinatal management planned in advance. This pathology is characterized by complete or partial obstruction of the fetal upper airway, laryngeal atresia being the most common cause. The atresia hinders the normal clearance of fluid secreted by the fetal lungs. The retained fluid causes secondary hyperplasia and hyper expansion of the lungs, which presses on the fetal heart, great mediastinal veins, and diaphragm. The augmented intrathoracic pressure causes a reduction in venous return that may lead to fetal ascites and hydrops. These findings can be visualized with obstetric sonography in the second and third trimesters and with magnetic resonance imaging (MRI). A case study is provided of a patient whose fetus was diagnosed with CHAOS, after findings of multiple congenital anomalies, as part of her routine second-trimester anatomical sonogram. Advanced treatment options currently available, like ex utero intrapartum treatment (EXIT) and fetoscopic laser laryngotomy, should be reserved for those patients without associated major congenital malformations that are incompatible with life. Even with medical innovations, in such management techniques, the fetal prognosis remains unfavorable.