Tracheal atresia

Tracheal atresia is an extremely rare anomaly and refers to a congenital absence of the trachea.

Epidemiology

There may be a greater male predilection ⁵.

Associations 

Associated anomalies can be present in up to 90% of cases ⁵:

• congenital high airways obstruction syndrome (CHAOS): some authors consider this as synonymous with tracheal atresia although the syndrome can occur with tracheal stenosis or laryngeal atresia/stenosis

• Fraser syndrome ¹⁰

• esophageal atresia with tracheo-esophageal fistula ⁷: tracheal atresia can occur in some of the subtypes

• polyhydramnios

• VACTERL association

Pathology

Tracheal atresia falls under the spectrum of laryngeal-tracheo-bronchial atresia which in turn results either from an obstructing lesion (i.e. cartilaginous bar) or vascular insult with atresia of the airways which occurs during intrauterine development.

Classification

The Floyd classification is sometimes used which is as follows

• type I: agenesis of proximal trachea with short segment normal distal trachea, carina and bronchi; a fistula is present between the distal trachea and esophagus

• type II: agenesis of the entire trachea; may be accompanied by a communication between esophagus and carina, from which the bronchi originate

• type III: atresia of entire trachea and carina; the bronchi originate individually from the esophagus

Radiographic features

Ultrasound

• may show uniformly increased echogenic enlarged lung +/- pleural effusions +/- fetal ascites

• markedly dilated fluid-filled bronchi may be seen

• may also show ancillary sonographic features such as the presence of polyhydramnios

• the fetal cardio-thoracic circumference ratio is decreased due to larger lung volumes

Differential diagnosis

General differential considerations include:

• laryngeal atresia: sometimes can be impossible to differentiate on imaging

• severe congenital tracheal stenosis