Citation, DOI, disclosures and article data
Citation:
Weerakkody Y, Campos A, Ashraf A, et al. Congenital high airway obstruction syndrome. Reference article, Radiopaedia.org (Accessed on 23 Feb 2025) https://doi.org/10.53347/rID-13887
Congenital high airway obstruction syndrome or sequence (CHAOS) refers to a rare, often lethal, congenital laryngotracheal condition and is primarily characterized by obstruction to the fetal upper airway.
Associations
CHAOS can be of three possible types 2:
Ultrasound
Ultrasound may show some or all of the following features 4,5:
dilated trachea/bronchi: distal to the obstruction
enlarged echogenic lungs
diaphragmatic inversion and/or flattening
fetal ascites
the fetal heart may appear displaced to the midline and compressed
Ancillary sonographic features include:
Fetal MRl
May confirm features detected on ultrasound as well as more accurately show the level of obstruction. Lung signal is increased 5.
Treatment and prognosis
The prenatal natural history and postnatal course of CHAOS often depend on whether the airway obstruction is complete. An ex utero intrapartum treatment (EXIT) procedure may offer potential for salvage 1,3. Overall prognosis is considered generally poor 6.
The differential diagnosis of echogenic fetal lung is congenital pulmonary airway malformation (CPAM) type III. In CHAOS, both lungs are echogenic, whereas CPAM is usually unilateral, but can be bilateral in rare cases. Dilated airway is another clue that is seen only in CHAOS 9-11.
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1. Lim FY, Crombleholme TM, Hedrick HL et-al. Congenital high airway obstruction syndrome: natural history and management. J. Pediatr. Surg. 2003;38 (6): 940-5. J. Pediatr. Surg. (link) - Pubmed citation
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2. Hartnick CJ, Rutter M, Lang F et-al. Congenital high airway obstruction syndrome and airway reconstruction: an evolving paradigm. Arch. Otolaryngol. Head Neck Surg. 2002;128 (5): 567-70. Arch. Otolaryngol. Head Neck Surg. (link) - Pubmed citation
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3. Shimabukuro F, Sakumoto K, Masamoto H et-al. A case of congenital high airway obstruction syndrome managed by ex utero intrapartum treatment: case report and review of the literature. Am J Perinatol. 2007;24 (3): 197-201. doi:10.1055/s-2007-972928 - Pubmed citation
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4. Mong A, Johnson AM, Kramer SS et-al. Congenital high airway obstruction syndrome: MR/US findings, effect on management, and outcome. Pediatr Radiol. 2008;38 (11): 1171-9. doi:10.1007/s00247-008-0962-2 - Pubmed citation
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5. Guimaraes C, Linam L, Kline-Fath B et al. Prenatal MRI Findings of Fetuses with Congenital High Airway Obstruction Sequence. Korean J Radiol. 2009;10(2):129-34. doi:10.3348/kjr.2009.10.2.129 - Pubmed
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6. Cavoretto P, Molina F, Poggi S, Davenport M, Nicolaides K. Prenatal Diagnosis and Outcome of Echogenic Fetal Lung Lesions. Ultrasound Obstet Gynecol. 2008;32(6):769-83. doi:10.1002/uog.6218 - Pubmed
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7. Kuwashima S, Kitajima K, Kaji Y et-al. MR imaging appearance of laryngeal atresia (congenital high airway obstruction syndrome): unique course in a fetus. Pediatr Radiol. 2008;38 (3): 344-7. doi:10.1007/s00247-007-0693-9 - Pubmed citation
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8. Biyyam D, Chapman T, Ferguson M, Deutsch G, Dighe M. Congenital Lung Abnormalities: Embryologic Features, Prenatal Diagnosis, and Postnatal Radiologic-Pathologic Correlation. Radiographics. 2010;30(6):1721-38. doi:10.1148/rg.306105508 - Pubmed
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9. Chaemsaithong P, Chansoon T, Chanrachakul B, Worawichawong S, Wongwaisayawan S, Promsonthi P. Prenatal diagnosis and pathology of laryngeal atresia in congenital high airway obstruction syndrome. (2012) Case reports in radiology. 2012: 616905. doi:10.1155/2012/616905 - Pubmed
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10. Padmanabhan L & Nampoothiri S. Prenatal Detection of Congenital High Airway Obstruction Syndrome with Encephalocele. Indian J Radiol Imaging. 2016;26(1):70-2. doi:10.4103/0971-3026.178336 - Pubmed
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11. Artunc Ulkumen B, Pala HG, Nese N, Tarhan S, Baytur Y. Prenatal diagnosis of congenital high airway obstruction syndrome: report of two cases and brief review of the literature. (2013) Case reports in obstetrics and gynecology. 2013: 728974. doi:10.1155/2013/728974 - Pubmed
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