ABSTRACT
Congenital upper airway obstruction syndrome is a rare malformation that can be fatal to a newborn baby. It is defined as a complete or almost complete obstruction of the upper airways. CHAOS rate is unknown. We here report the case of a 24-year-old primiparous patient with no medical or surgical history. First-trimester ultrasound didn't show any abnormality. During the second trimester, ultrasonography showed extensive subcutaneous edema, hypertrophied lung with hyperechoic appearance, hypoplastic heart and large-volume ascites associated with severe oligoamnios. After having excluded the most common causes, including isoimmunization (indirect negative Coombs), infections (negative serologies) kariotiping was not performed because the patient refused it. The results of ultrasonography suggested fetal hydrops secondary to CHAOS syndrome, because of pathognomonic signs of pulmonary hypertrophy with inverted or convex diaphragm. MRI was requested; it suggested CHAOS syndrome associated with other malformations: laryngeal atresia, microphthalmia with hypertelorism and deviation of the nasal septum with lack of visualization of the thymic tissue, no clear identification of the bladder, absence of right kidney and hypoplastic left kidney. The outcome of pregnancy was marked by premature labour at the 24th week of amenorrhea. The baby had a birth weight of 1475g, polimalformations such as sexual ambiguity, distended abdomen and polydactyly . The newborn died 3 min after birth. Karyotyping was performed which showed 46XX.