Normal Newborn Nose

Children and adults preferentially breathe through their nose unless nasal obstruction interferes. Most newborn infants are obligate nasal breathers and significant nasal obstruction presenting at birth, such as choanal atresia, may be a life-threatening situation for the infant unless an alternative to the nasal airway is established. Nasal congestion with obstruction is common in the 1st year of life and can affect the quality of breathing during sleep; it may be associated with a narrow nasal airway, viral or bacterial infection, enlarged adenoids, or maternal estrogenic stimuli similar to rhinitis of pregnancy. The internal nasal airway doubles in size in the 1st 6 mo of life, leading to resolution of symptoms in many infants. Supportive care with a bulb syringe and saline nose drops, topical nasal decongestants, and antibiotics, when indicated, improve symptoms in affected infants.

Physiology

The nose is responsible for olfaction and initial warming and humidification of inspired air. In the anterior nasal cavity, turbulent airflow and coarse hairs enhance the deposition of large particulate matter; the remaining nasal airways filter out particles as small as 6 µm in diameter. In the turbinate region, the airflow becomes laminar and the airstream is narrowed and directed superiorly, enhancing particle deposition, warming, and humidification. Nasal passages contribute as much as 50% of the total resistance of normal breathing. Nasal flaring, a sign of respiratory distress, reduces the resistance to inspiratory airflow through the nose and can improve ventilation (Chapter 365).

Although the nasal mucosa is more vascular, especially in the turbinate region than in the lower airways, the surface epithelium is similar, with ciliated cells, goblet cells, submucosal glands, and a covering blanket of mucus. The nasal secretions contain lysozyme and secretory immunoglobulin A (IgA), both of which have antimicrobial activity, and IgG, IgE, albumin, histamine, bacteria, lactoferrin, and cellular debris, as well as mucous glycoproteins, which provide viscoelastic properties. Aided by the ciliated cells, mucus flows toward the nasopharynx, where the airstream widens, the epithelium becomes squamous, and secretions are wiped away by swallowing. Replacement of the mucous layers occurs about every 10-20 min. Estimates of daily mucus production vary from 0.1-0.3 mg/kg/24 hr, with most of the mucus being produced by the submucosal glands.

Congenital Disorders

Congenital structural nasal malformations are uncommon compared with acquired abnormalities. The nasal bones can be congenitally absent so that the bridge of the nose fails to develop, resulting in nasal hypoplasia. Congenital absence of the nose (arhinia), complete or partial duplication, or a single centrally placed nostril can occur in isolation but is usually part of a malformation syndrome. Rarely, supernumerary teeth are found in the nose, or teeth grow into it from the maxilla.

Nasal bones can be sufficiently malformed to produce severe narrowing of the nasal passages. Often, such narrowing is associated with a high and narrow hard palate. Children with these defects can have significant obstruction to airflow during infections of the upper airways and are more susceptible to the development of chronic or recurrent hypoventilation (Chapter 17). Rarely, the alae nasi are sufficiently thin and poorly supported to result in inspiratory obstruction, or there may be congenital nasolacrimal duct obstruction with cystic extension into the nasopharynx, causing respiratory distress.

Choanal Atresia

This is the most common congenital anomaly of the nose and has a frequency of ∼1/7,000 live births. It consists of a unilateral or bilateral bony (90%) or membranous (10%) septum between the nose and the pharynx; most cases are a combination of bony and membranous atresia. About 50-70% of affected infants have other congenital anomalies, with the anomalies occurring more often in bilateral cases. The CHARGE syndrome (coloboma, heart disease, atresia choanae, retarded growth and development or CNS anomalies or both, genital anomalies or hypogonadism or both, and ear anomalies or deafness or both) is one of the more common anomalies associated with choanal atresia. Most patients with CHARGE syndrome have mutations in the CHD7

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