Camelidae and Cervidae Congenital Respiratory Defects – NAVLE Study Guide

Overview and Clinical Importance

Congenital respiratory defects in camelids (llamas, alpacas, vicunas, guanacos) and cervids (deer, elk, moose) represent significant clinical challenges in veterinary practice. These defects primarily affect the upper respiratory tract and can be life-threatening in neonates. Understanding these conditions is critical for the NAVLE because camelids are obligate nasal breathers, making any obstruction of the nasal passages potentially fatal.

The two most clinically significant congenital respiratory defects covered in this guide are choanal atresia (failure of the posterior nasal openings to develop) and maxillofacial dysgenesis (wry face/wry nose), which involves lateral deviation of the facial bones causing airway obstruction. Both conditions require prompt recognition and appropriate management decisions.

Choanal Atresia

Definition and Embryology

Choanal atresia (CA) is a congenital defect resulting from the failure of the posterior nasal openings (choanae) to communicate with the nasopharynx. During normal fetal development, the nasal cavity and nasopharynx develop as separate cavities that eventually join at paired openings called the choanae. In choanal atresia, the buccopharyngeal membranes fail to completely rupture during the early second trimester, leaving membranous or bony obstructions over one or both nasal passages.