Chapter 53: Pediatric Otolaryngology

General Information

This chapter focuses on otolaryngologic issues in children. The chapter is divided into (1) ears and hearing; (2) nose, nashopharynx, and paranasal sinuses; (3) mouth and upper digestive tract; (4) airway; and (5) head and neck.

Ears and Hearing

Outer Ear (Pinna, External Auditory Canal [EAC], Tympanic Membrane[TM])

Developmental Anatomy

1. Prenatal development

   1. 5 weeks’ gestation

      1. Auricle develops from first (mandibular) and second (hyoid) arches that give rise to six Hillocks of His.

      2. Controversial, but first Hillock gives rise to tragus, second to helical crus, third to remainder of helix, fourth to antihelix, fifth to antitragus, sixth to lobule. Lobule is last to form and some feel not derived from Hillocks.

   2. 8 weeks’ gestation

      1. Cartilaginous (outer third) of EAC derived from invagination of concha cavum (first branchial groove).

      2. Bony EAC (inner two-thirds) derived from invagination of meatal plug (solid epithelial core) from primary meatus to primitive tympanic cavity to form meatal plate.

   3. 21 weeks’ gestation

      1. Epithelial cells resorb to canalize bony EAC. Incomplete resorption results in atresia or stenosis.

      2. Tympanic membrane has three layers.

         1. Outer epithelial layer from ectoderm of first branchial groove.

         2. Middle fibrous layer.

         3. Inner mucosal layer from endoderm of first pharyngeal pouch.

         4. Pars tensa composed of three layers. Pars flaccida composed of two (outer and inner) layers. Perforations in pars tensa that heal and look thin are composed of outer and inner layers (missing middle layer) and should be called dimeric membrane (rather than monomeric membrane which is a misnomer).

2. Postnatal development

   1. Medial EAC ossifies by 2 years of age and reaches adult size by 9 years of age.

   2. TM almost adult size at birth but horizontally oriented. Becomes more vertical as EAC lengthens.

   3. Pinna is 80% of adult size by age 5, adult size by age 9. Lobule may continue to grow thereafter.

Signs and Symptoms

Visible lesion, drainage, infection, abnormally shaped pinna.

Clinical Assessment

Close inspection of pinna and remainder of head and neck for associated features as described below.

Pathologies

Congenital

1. Preauricular tag

   1. Most common ear anomaly.

   2. Due to supernumerary hillock formation.

   3. May be associated with branchio-oto-renal (BOR) syndrome involving hearing loss, branchial cleft cyst, and renal anomalies or other craniofacial syndromes.

   4. May be removed electively.

2. Preauricular pit

   1. Likely due to failure of fusion of hillocks.

   2. Most commonly at helical root. Pit below tragus more likely to be first branchial cleft anomaly.

   3. May be associated with BOR.

   4. Acute infection warrants antibiotics and drainage if necessary.

   5. Definitive excision after resolution of inflammation. Removal of entire tract plus cartilage at base of tract is necessary to prevent postoperative infection and recurrence.

3. Protruding ears

   1. Larger than average distance from helical rim to mastoid.

   2. Usually bilateral.

   3. Due to under development of antihelix ...