Choanal atresia

What it is

Choanal atresia is a congenital disorder in which the back of the nasal airway is blocked. It is one of the chronic congenital causes of stridor, alongside laryngomalacia, vallecular cysts, thyroglossal cysts and tongue dermoid or teratoma. Stridor itself is a monophonic, high-pitched inspiratory sound caused by narrowing of the upper or central airway.

Causes and risk

Atresia of the choanae is one of the major diagnostic criteria of CHARGE syndrome; the first of the four is ocular colobomas and the second is choanal atresia itself. The acronym stands for coloboma of the eye, heart defects, atresia of the choanae, retarded growth and development, genital abnormalities and ear anomalies. The diagnostic criteria are set out as major and minor. The four major criteria are:

1. Ocular colobomas.
2. Choanal atresia.
3. Cranial nerve dysfunction: anosmia, facial palsy, auditory nerve hypoplasia.
4. Ear anomalies.

The diagnosis is made with 4 major criteria, or with 3 major and 3 minor. With 1 or 2 major and several minor it is likely only. The minor criteria are eight, the first genital hypoplasia and the second developmental delay, then cardiovascular anomalies, cleft lip and/or palate, tracheoesophageal fistula or esophageal atresia, facial dysmorphology (square face, prominent forehead, flat midface), growth failure, and the hockey stick palmar crease. CHARGE syndrome is inherited as autosomal dominant, and the gene named for it is CHD7. The most common cardiac defect in it is tetralogy of Fallot, with conotruncal defect and arch anomalies named alongside.