For many individuals, the diagnosis of aerodigestive tract disease begins in the prenatal phase. A “Triple Test” is available in the first trimester and combines a measurement of nuchal thickness on ultrasonography, maternal age, gestational age, and maternal serologic measurements of PAPP-A and beta hCG to predict the risk of trisomy 21, 18, and 13 as well as Beckwith-Wiedemann syndrome in the developing fetus (17,18). Second trimester screening can add serologic evaluation of inhibin-A and alpha-fetoprotein, constituting a “Penta test” which, when considered alongside the first trimester combined screening results, provides a more sensitive prenatal diagnosis of aneuploidy and neural tube defects (19,20). Invasive measures, such as chorionic villus sampling (CVS) in the late first trimester of pregnancy and amniocentesis in the second trimester, may identify individuals with chromosomal anomalies that place them at risk for postnatal problems, including aerodigestive tract dysfunction. Later in the second trimester of pregnancy, biometric measures of oral, oropharyngeal, and laryngotracheal structures can be obtained using fourplane sonography techniques. Individuals followed over time with ultrasonography demonstrate not only anatomic but also physiologic development, as increasingly complex orofacial, lingual, pharyngeal, and laryngeal movements indicate the evolution of suckling behavior. Further, children with genetic abnormalities identified through a Triple/Quad/Penta test, CVS, and/or amniocentesis demonstrate suckling dysfunction on prenatal ultrasonography compared to individuals without disease (21) (Fig. 87.3).

Because ultrasound is anatomical, physiologic, and noninvasive, it is currently the most important and commonly used means to diagnose aerodigestive disease prenatally. However, the application of fetal MRI is widening, and several reports exist documenting the utility of prenatal MRI in the diagnosis of aerodigestive tract anomalies that may predict respiratory embarrassment at delivery (Fig. 87.4). At many institutions, protocols are being developed to employ high-quality ultrasonography and fetal MRI in a complementary fashion to determine which patients should be offered ex utero intrapartum treatment (EXIT) to establish an airway (22). The utility of prenatal MRI likely will continue to evolve (23,24).

As with any disease process, the diagnosis of congenital aerodigestive tract disease begins with a history and physical examination. Even in the management of an emergent airway obstruction, some modicum of historical information and physical observations guide the clinician to the appropriate urgent intervention. When evaluating a stable patient with congenital aerodigestive tract disease, a comprehensive history and physical examination may be obtained alongside flexible endoscopy and selected
imaging. In an unstable patient, diagnosis and management often occur at the same time in the operating room in the process of securing a safe airway.

The functions of the aerodigestive tract include breathing, feeding, and voicing. Aerodigestive disease frequently affects more than one of these functions simultaneously, and a useful history not only focuses in on the diagnosis but also accounts for the variety and degree of disabilities the patient is experiencing. Noisy, rapid, and/or labored breathing is representative of respiratory dysfunction. Adventitious breath sounds include stertor, snorting, snoring/sonorous breathing, stridor, wheezing, and coughing. When these signs are present on inspiration, the airflow limitation is usually above the level of the vocal folds. Biphasic stridor is classically glottic or subglottic, while expiratory stridor originates below the larynx. The timing, severity, relapsing and remitting factors, effects of positional changes and effects on feeding must be clarified, and such useful historical information may be obtained from the family, nursing staff, respiratory therapists, speech pathologists and the primary physician team managing the patient. For safe feeding to occur, the infant must have a reasonably slow respiratory rate to allow suck-swallow-breathe coordination, and nasal breathing is required for this coordinated effort until around the eighth month of life. How breathing is affecting feeding, the technique (breast, standard bottle, specialized feeder/nipple) and position of feeding, the consistency of oral intake and any signs of choking, coughing, wet sounding respirations, desaturations, and the presence or absence of pneumonia are all important questions to ask. Spitting up and emesis are also important to ascertain, as retrograde esophageal movement may lead to aspiration of refluxate or point to a pharyngoesophageal anomaly. Finally, the quality, quantity, and volume of voicing must be determined.

The physical examination of the infantile aerodigestive tract must account for the unique craniofacial relationships in the infant. The head is relatively large while the neck is relatively small in circumference and short in length. The midface is flattened, and the retropalatal and retrolingual airspaces are relatively compressed compared to their adult counterparts (25). In fact, the tip of the epiglottis may touch the tip of the soft palate during deglutition, indicating the high position of the infant’s larynx in the neck. The inferior margin of the cricoid cartilage is at C2 in the newborn and at C7 in the adult. With this in mind, the physical examination again focuses on the presence and degree of respiratory, feeding, and communication difficulties being experienced by the patient. The examination begins by noting the patient’s color, body position, and apparent level of distress. Respiratory rate, effort, and sound are all noted, as are the presence, location, and severity of retractions. The presence of labored breathing with retractions is more serious than of loud breathing without effort or retractions. As less and less air movement occurs, the patient may become quieter as a consequence. The clinician should also note pulse oximetry data and whether the patient is receiving supplemental oxygen. The cry should be assessed for hoarseness, breathiness, or aphonia. Observing the infant during a feeding gives useful insight into suck-swallow-breathe coordination, signs of aspiration, and the overall safety of oral feeding.

The history and physical examination often point to the diagnosis of congenital aerodigestive tract disease, but additional diagnostics commonly are called upon to both confirm the diagnosis and stage the extent of comorbidities. A significant minority of patients have multiple congenital aerodigestive abnormalities (26). In a stable patient, after a detailed history and physical examination, a common next step is flexible nasopharyngoscopy and laryngoscopy. With an appropriately sized flexible scope (around 2.2 mm outer diameter or smaller), nasopharyngoscopy is well tolerated and safe without topical anesthetic (which might confound a flexible endoscopic evaluation of swallowing [FEES]). Flexible endoscopy allows the examiner to diagnose the nature of the disease, the level(s) of disease, and any dynamic airway collapse. The position of the patient matters in flexible nasopharyngoscopy. The larynx is best visualized when the patient is in a seated position as it allows the pharynx to open and the larynx to fall forward. However, neonates do not assume a seated position, and flexible endoscopy in their typical supine, side-lying or reverse-Trendelenburg position will best recapitulate obstruction and aerodigestive tract dysfunction as they experience it (Fig. 87.5). Concomitant administration of dyed liquids, purees, and solids allows the examiner to assess swallowing safety and dysfunction endoscopically (FEES). Importantly, what is seen on flexible endoscopy
may also guide airway management when the patient undergoes treatment in the operating room.

In addition to flexible endoscopy, radiographic studies provide diagnostic and staging information in the stable patient. Plain films of the neck in anterior-posterior and lateral planes highlight the soft tissue relationships around the air column. However, most clinicians prefer the anatomical detail, multiplanar information, and surgical roadmap provided by computerized tomography (CT). Indeed, CT scanning is the initial imaging modality of choice for craniofacial, nasal, nasopharyngeal, oral, and oropharyngeal aerodigestive diseases (27,28,29). MRI also provides exceptional anatomical detail, but its added cost and absolute need for sedation render MRI less frequently employed. Dynamic radiographic studies continue to be useful in the diagnosis of aerodigestive diseases, and while airway fluoroscopy is of historical interest, cine MRI allows the clinician to determine anatomical levels of airway collapse under a plane of anesthesia that simulates sleep in patients with sleep-disordered breathing (30,31). Finally, a videofluoroscopic swallow study (VFSS or modified barium swallow study) remains an indispensable tool to diagnose dysphagia, make treatment recommendations, and occasionally directly see the effects of aerodigestive tract anomalies on swallowing (32).

Following an appropriate history and physical examination supplemented by appropriate imaging, rigid airway endoscopy is the gold standard in the diagnosis of aerodigestive tract disease. Nasal and nasopharyngeal lesions require nasal endoscopy/nasopharyngoscopy, whereas oral, oropharyngeal, hypopharyngeal, laryngeal, tracheobronchial, and esophageal diseases are diagnosed by microlaryngoscopy, bronchoscopy, and esophagoscopy. Diagnostic airway endoscopy requires careful preparation and adequate equipment to deal with expected and unexpected scenarios in the management of the patient’s airway. The otolaryngologist must communicate with the anesthesia team their goals and expectations from the evaluation. Most rigid airway endoscopy in the operating room is performed with the patient anesthetized but spontaneously breathing. This allows a greater margin of safety as the patient is capable of unassisted gas exchange, and there is greater time to examine the airway before desaturation requires bagging or intubation. In this technique, topical anesthetic must be sprayed on the larynx and tracheobronchial tree to reduce laryngospasm and coughing. In neonates, 0.5% to 2% plain lidocaine typically is used. The exact technique of rigid airway endoscopy varies from surgeon to surgeon. Batterypowered intubation laryngoscopes (e.g., Miller, Phillips, or Wis-Hippel blade) and operating laryngoscopes with external light sources are both useful to examine the oral cavity, oropharynx, hypopharynx, and larynx. The operating laryngoscopes can be suspended for a two-handed stable examination and intervention as needed. Magnifying telescopes (Hopkins rod telescopes) are commonly used to enhance the examination and allow digital photo/video documentation. These scopes can be used independently with an intubation laryngoscope or with an operating laryngoscope. Alternatively, an operating microscope can be used with suspension laryngoscopy to evaluate and treat the larynx. Tracheobronchoscopy can be performed with a bare telescope passed through the glottis or with a ventilating bronchoscope containing a telescope. Advantages of the latter are obvious—the bronchoscope may be connected to the anesthetic circuit and the patient ventilated while the examination is taking place. However, the limiting factor in tracheobronchoscopy is the size of the patient’s airway, and a much larger (and higher optical resolution) bare telescope can be passed into a small airway without the sheathing ventilating bronchoscope (Fig. 87.6). Operative rigid endoscopy is also the platform from which airway management, biopsies, and endoscopic therapies take place.

With an overview of aerodigestive disease diagnosis in mind, specific levels of aerodigestive tract dysfunction are detailed below. Key symptoms uncovered in a careful history, significant findings on physical examination, and other typical diagnostic results are highlighted.

The symptoms and signs of nasal obstruction are sonorous or snorting inspiratory breath sounds with mild to moderate obstruction progressing to cyclic cyanosis relieved by crying and mouth breathing with complete nasal obstruction. Affected infants are poor feeders due to interruption of the suck-swallow-breathe mechanism. Voicing may be hyponasal. Flexible nasal endoscopy may note a tight anterior nasal valve secondary to congenital nasal pyriform aperture stenosis (CNPAS), an anomaly within the nasal passageway, or pooled secretions in the posterior
nasal passageway secondary to choanal stenosis or atresia. A high-resolution maxillofacial CT scan with axial, coronal, and sagittal reconstructions and/or three-dimensional (3-D) reconstruction is the single most useful radiographic study in the evaluation of congenital nasal anomalies because of its superior bony/soft tissue resolution (33,34). Rigid nasal endoscopy adds little to the diagnosis, but it is a platform from which both diagnosis and treatment can be instituted.

The symptoms and signs of congenital nasopharyngeal anomalies are largely the same as nasal ones. One exception is cysts or tumors (such as teratomas) that exert a mass effect on the nasal surface of the soft palate. In these instances, if the soft palate is stented open by a mass descending behind the palate, voicing is hypernasal secondary to velopharyngeal incompetence. If the entire nasopharyngeal space is obliterated, the cry is muffled. Again, flexible endoscopy is an indispensable diagnostic tool, especially as the scope tip can be rotated to evaluate all recesses of the nasopharynx, and a flexible nasopharyngoscope may be twisted through a stenotic choana. In these respects, flexible endoscopy is superior to rigid in the nasopharynx. As with nasal lesions, a high-resolution maxillofacial CT scan with axial, coronal, and sagittal reconstructions and/or 3-D reconstruction is the most useful radiographic study in the evaluation of congenital nasopharyngeal anomalies (Fig. 87.7) (33,34).

Congenital aerodigestive tract anomalies affecting the oral cavity are heterogeneous, ranging from abnormal bands, such as upper labial frenulum, ankyloglossia, and intergnathic bands, as seen in popliteal pterygium syndrome (35,36) to cleft palate to macroglossia, as seen in Beckwith-Wiedemann Syndrome (Fig. 87.8)
(37,38). The symptoms and signs of minor anomalous bands largely relate to feeding, as the inability to evert the upper lip or protrude the tongue may preclude effective breastfeeding. Airway and voicing are unaffected. Similarly, cleft palate (without micrognathia and/or relative macroglossia) is mostly a feeding problem at birth. In contrast, microstomia, intergnathic bands, micrognathia with relative macroglossia, absolute macroglossia and intraoral tumors produce drooling, gasping during feeding, muffled cry, and obstructed breathing patterns. When no oropharyngeal obstruction is present, quiet breathing through the nose may be unaffected. Nasopharyngoscopy rules out oropharyngeal extension, but the majority of the salient physical exam can be accomplished through direct observation with a tongue depressor and a headlamp. Consistent with the heterogeneous nature of congenital oral anomalies, there is no single imaging modality that is required or preferred for diagnosis. When the physical examination alone is insufficient, mandibular or dentigerous anomalies may be evaluated best with a panorex. Relationships between the upper and lower jaws and the encompassed soft tissue are best shown on a maxillofacial CT scan, while intrinsic soft tissue lesions (such as lingual masses) achieve best delineation on MRI (39). For vascular malformations, MRI adds the benefit of vascular phases that provide additional diagnostic sensitivity (MR angiography [MRA] and MR venography (40)).

Moving inferiorly, the oropharyngeal space becomes the common aerodigestive tract in the nasal-breathing neonate. Symptoms and signs of congenital oropharyngeal anomalies include wet stertorous breath sounds, inspiratory stridor, snoring, gasping, discomfort and possibly cyanosis with feeding, and a muffled cry. Patients often breathe better in the prone position (which is also true for patients with stridor of a supraglottic etiology). Aspiration is likely with larger lesions due to suck-swallow-breathe interruption. Flexible endoscopy is essential to the diagnosis of oropharyngeal congenital anomalies because it provides a dynamic assessment of breathing, the management of secretions, and any effects the oropharyngeal lesion is exerting on the larynx—particularly with vallecular cysts that tend to drive the epiglottis into the glottic inlet (41). With oropharyngeal lesions, imaging may not be necessary. Important relationships to define are mostly soft tissue relationships, and MRI provides the best resolution. However, increased speed, decreased cost, and the possibility of avoiding sedation often support the use of a contrast-enhanced CT, which provides adequate anatomic delineation, particularly for cystic anomalies. Both for diagnosis and for airway management, rigid microlaryngoscopy and bronchoscopy are indicated if the oropharyngeal lesion abuts the larynx/hypopharynx.

Anomalies of the hypopharynx produce dysphagia, muffled voicing, and airway obstruction by interfering with the esophageal inlet and/or the patency and movement of the larynx. Stridor is inspiratory, and the abnormal collection of hypopharyngeal secretions may lead to wet sounding respirations. Similarly, a large lesion of the hypopharynx, which directs secretions and oral intake into the larynx, produces coughing and aspiration. Flexible endoscopy is essential to diagnose the lesion and to assess its dynamic effects on the management of secretions, swallowing, and breathing. As with oropharyngeal lesions, imaging may be unnecessary, but a contrast-enhanced CT and MRI both provide adequate anatomic detail to resolve hypopharyngeal lesions. Dysphagia is common with hypopharyngeal anomalies, and VFSS is necessary to complete the workup in most instances (Fig. 87.9) (32). Microlaryngoscopy, bronchoscopy, and esophagoscopy complete the evaluation, and postcricoid lesions are evaluated specifically by lifting the larynx with the laryngoscope blade during a comprehensive exam.

The larynx has three cardinal functions: (a) an airway protection mechanism during swallowing, (b) a respiratory conduit, and (c) a phonatory source. These functions are carried out over a relatively small area, and their success depend on intact sensation and movement (glottic abduction, adduction, and laryngeal elevation), laryngeal patency, and the ability of thin, crisp vocal folds to be pulled together and driven by an adequate subglottic air column. The symptoms and signs of aerodigestive disease in the
larynx include dysphagia and aspiration with or without coughing and recurrent aspiration pneumonias. Stridor is present and is classically described as inspiratory when the lesion is supraglottic or glottic and biphasic when the lesion is subglottic. Stridor may progress to retractions and cyanosis. When stridor is absent at birth but appears in the first few weeks or months of life, laryngomalacia is the most likely cause, although subglottic hemangiomas also usually present with some delay. Vocal dysfunction due to laryngeal disease may be muffled or coarse if there is a large supraglottic lesion, hoarse, breathy, or aphonic if the disease is glottic, and hoarse and breathy if the disease is subglottic.