Paradoxical expiratory ballooning of the hypopharynx in siblings with bilateral choanal atresia.

Abstract

Atresia of the posterior choanae is a relatively rare congenital anomaly, cases of which may be classified as unilateral or bilateral, complete or incomplete, and membranous, osseous, or mixed. The majority of patients with this disorder are said to have osseous obstruction, with thickness of bone varying from a few millimeters to more than 12 millimeters. The central portion of the obstruction is usually thinner and may be membranous. To explain the abnormality on a developmental basis, persistence of the bucconasal membrane is postulated. This structure usually ruptures in the thirty-five-day to thirty-eight-day embryo, forming the primitive choanae. Persistence of the portion of the buccopharyngeal membrane above the palate is suggested as a secondary cause, while a third possibility offered is overgrowth of the vertical and horizontal palatal processes. A familial incidence has been reported (1–s6). Roentgen studies of choanal atresia usually emphasize demonstration of the obstruction by a contrast medium in the nasal cavity (7) and the finding of abnormal bony structures (Fig. 1). The authors, however, recently had an opportunity of making some interesting fluoroscopic observations on two brothers with complete bilateral choanal atresia, in whom the paradoxical distention of the hypopharynx during expiration was so striking that it was deemed worthy of report. The embryological aspects of these cases are to be discussed elsewhere by our colleagues in otolaryngology (8). In the normal infant and in early childhood, as pointed out by Pancoast (9), “during the inspiratory phase the pharynx is often filled with air and the post-pharyngeal space is comparatively narrow. During expiration the space may be much wider, when the pharyngeal space is completely or partially collapsed.” Hay (10) also emphasized the presence of air in the pharynx in the inspiratory phase, and his excellent illustrations demonstrate the relative distention of the hypopharynx during inspiration, in contrast to its collapse during expiration. The disturbance of the mechanics of respiration in our cases of complete bilateral atresia was productive of a striking reversal of these normal findings. Case I: The patient was a male infant born at term Aug. 28, 1950, with normal vaginal delivery after a short labor. He cried soon after birth, but in a few minutes stopped breathing and an airway was introduced. His hands and feet were cyanotic at that time. He experienced considerable difficulty in eating and was kept in an oxygen tent most of the time. A diagnosis of posterior choanal atresia was made, and the possibility of an associated congenital anomaly of the heart was also considered.