Choanal atresia

Choanal atresia is a congenital disorder where the back of the nasal passage (choana) is blocked, usually by abnormal bony or soft tissue (membranous) due to failed recanalization of the nasal fossae during fetal development. It was first described by Roederer in 1755.
Presentation.
It can be unilateral or bilateral.
Associated conditions.
Sometimes babies born with choanal atresia also have other abnormalities:
Also any condition that causes significant depression of the nasal bridge or midface retraction can be associated with choanal atresia. Examples include the craniosynostosis syndromes such as Crouzon syndrome, Pfeiffer syndrome, Treacher Collins and Antley-Bixler syndrome.
Risk factors.
Very few risk factors for choanal atresia have been identified. While causes are unknown, both genetic and environmental triggers are suspected. One study suggests that chemicals that act as endocrine disrupters may put an unborn infant at risk. A 2012 epidemiological study looked at atrazine, a commonly used herbicide in the U.S., and found that women who lived in counties in Texas with the highest levels of this chemical being used to treat agricultural crops were 80 times more likely to give birth to infants with choanal atresia or stenosis compared to women who lived in the counties with the lowest levels. Another epidemiological report in 2010 found even higher associations between increased incidents of choanal atresia and exposure to second-hand-smoke, coffee consumption, high maternal zinc and B-12 intake and exposure to anti-infective urinary tract medications. The anti-thyroid medication methimazole has been associated with the development of choanal atresia in rare cases if given during the first trimester of pregnancy.
Diagnosis.
Choanal atresia can be suspected if it is impossible to insert a nasal catheter.
Also, if one notices a continuous stream of mucus draining from one or both nostrils, it could be a sign of an atresia. Another common sign is cyanosis in an infant while breast feeding, as breathing is dependent on nasal patency in this situation.
Diagnosis is confirmed by radiological imaging, usually CT scan.
In 1950, in Franklin County, NY, a nurse noticed that a day-old infant turned blue when bottle-fed. “There is something wrong with the baby. We are sending her to Montreal!” The baby was hospitalized over a year. The ENT Surgeon had to gerry-rig a dental drill to accomplish the repair. In 2020, neonatal care for bilateral choanal atresia is much improved.
Treatment.
A stent may be inserted to keep the newly formed airway patent or repeated dilatation may be performed.
In popular culture.
In the movie City of Angels, Dr. Maggie Rice (played by Meg Ryan) correctly diagnoses the cause of a newborn baby's failure to thrive as due to choanal atresia.