Creating order out of chaos : role of antenatal ultrasound in diagnosis

Background: Congenital high airway obstruction syndrome (CHAOS) is a rare fetal anomaly characterized by obstruction of the higher fetal airway. This could be either complete or incomplete and is more commonly seen at the subglottic level, resulting in a spectrum of characteristic secondary features. Case Report: In this case study, we report two cases of CHAOS with one showing laryngeal atresia and the other, tracheal atresia. Both these cases showed characteristic findings on a detailed, meticulous USG examination which led to this diagnosis. Conclusions: Early and accurate diagnosis offers a window of opportunity for parental counseling and management using procedures such as EXIT (ex-utero intrapartum procedure). Earlier, CHAOS was thought to be incompatible with life; however, with the advent of ex-utero intrapartum procedure, a few cases of post-natal survival have been noted in the literature. In this article, we emphasize the sonographic findings found in CHAOS. Early diagnosis offers an opportunity for a intrauterine fetal intervention in potentially lethal cases