SPR Unknown #48 -- FINAL

Maria Calvo, MD


SPR unknown 48, CHAOS, fetal MRI, Congenital high airway obstruction sequence

Publication Date: 2011-04-01


23 week male fetus referred as “bilateral CPAM and ascites


Fetal Ultrasound (images 1 & 2) and MRI (image 3) demonstrate a dilated central airway; both lungs are markedly increased in volume with inversion of both hemidiaphragms and with centrally positioned and compressed heart. Both lungs appear diffusely echogenic on ultrasound and with increased T2 signal on MR. Large amount of ascites is also present. Coronal MRI image shows also horseshoe kidney.


Congenital high airway obstruction sequence (CHAOS).


The primary abnormality in congenital high airway obstruction sequence (CHAOS)is intrinsic obstruction of the airway. It leads to decreased clearance of fluid produced by the fetal lungs resulting in hyperexpansion, compressing the heart and inferior vena cava, leading to nonimmune hydrops. Identification of the airway obstruction is key to establish this diagnosis and differentiate from bilateral lung masses such as congenital pulmonary airway malformation (CPAM) or other causes of extrinsic airway obstruction such as a double aortic arch. Fetal MRI will help to localize the exact level of obstruction. CHAOS patients are delivered via EXIT (ex utero intrapartum treatment procedure) to tracheostomy.

3 images