Congenital High Airway Obstruction Syndrome (CHAOS): A perinatal autopsy case report

Congenital High Airway Obstruction Syndrome (CHAOS) is a rare anomaly where a partial or complete obstruction of upper airway is seen. As a consequence, the foetus develops enlarged lungs, inverted or flattened diaphragm and ascites. The pathological findings in a case of CHAOS is presented.

A 28-year-old primigravida presented with a history of 5 months of amenorrhoea. Ultrasonography revealed enlarged echogenic lungs, cardiac mid-position, inverted diaphragm, foetal ascites and talipes of left foot. The parents opted for termination of pregnancy. Foetal autopsy revealed a male foetus with ascites and talipes of left foot. Lungs were massively enlarged, diaphragm was flattened. A dome-shaped cricoid cartilage at the subglottic level was seen as the cause of obstruction.

CHAOS is a rare anomaly. A foetal autopsy can be helpful in establishing the level and nature of the obstruction and in documenting other associated foetal anomalies.