Congenital high airway obstruction syndrome complicated with foregut malformation and high airway fistula to the alimentary tract – a case series with four distinct types

Congenital high airway obstruction syndrome (CHAOS) is a rare disease and recently has been noticed to show typical prenatal images, such as hyperinflated lungs and flattened or inverted diaphragms. However, in some cases correct diagnosis may be difficult and in such cases the mortality rate increases.Case presentation We report four cases of CHAOS complicated with a high airway fistula to the alimentary tract and foregut malformation. The patients did not show the typical features of CHAOS in the fetus. This may be attributed to the high airway fistula acting as a decompression route for the accumulated lung fluids to the alimentary tract.Conclusion The combination of CHAOS, foregut malformation and a high airway fistula is very rare and classified into four distinct types: (1) CHAOS with a high airway fistula but not with a foregut malformation; (2) CHAOS with esophageal atresia and tracheoesophageal fistula; (3) CHAOS with a high airway fistula and duodenal atresia; and (4) CHAOS with esophageal atresia, tracheoesophageal fistula and duodenal atresia. It may be useful for treating physicians to be aware of these four distinct types and the typical characteristics of each type.