1. Diagnosing a Noisy Breather: Stridor in infants
Joshua Bedwell, MD, FAAP, FACS
Texas Children’s Hospital

2. Objectives Identify common causes of stridor in children
Discuss the appropriate evaluation and workup
Discuss the management options

3. Definitions & Anatomic Divisions
Stertor = snoring = nasal/pharyngeal airway Stridor = upper airway (Supraglottis, glottis, subglottis, trachea) Wheezing = lower airway (bronchi)
Stertor is a low-pitched, snoring sound typically caused by obstruction at the nasal, nasopharyngeal, or oropharyngeal level.
Typically, stridor is described as a high-pitched noise, though it can vary widely in pitch and quality.
Stridor is commonly found with supraglottic, glottic, or subglottic obstruction
Source: Cancer.gov

4. Airway Resistance
Poiseuille’s law: flow varies inversely with radius to the 4th power
Small decreases in radius (croup, subglottic stenosis) lead to big increases in resistance
Poiseuille’s law states that flow is inversely proportional to the fourth power of the radius. In the already small pediatric airway, tiny impingements on the lumen can create large increases in resistance.

5. Airway Resistance Turbulent flow increases resistance
Anything in the airway disrupting laminar flow will cause an increase in resistance and work of breathing.

6. Characterizing the Problem
Age at onset: congenital, acquired
Onset: gradual, worsening, abrupt
Severity: respiratory distress, increased WOB, retractions
Timing: With feeds? Constant? Positional?
Children present with stridor along a continuum of acuity and severity. At one end of the spectrum lies the stridulous child in acute respiratory distress, and at the other, the otherwise asymptomatic child who is noted to “squeak” a bit when feeding. In any child presenting in acute distress, the establishment of a safe and secure airway is paramount. Important historical points that may be quickly elucidated to aid in determining the safest management of the airway include the presence of trauma, suspicion of foreign body ingestion or aspiration, or signs and symptoms of acute infection (fever, malaise, etc.).
The age of onset is an important clue. Stridor apparent from the time of birth commonly points toward a congenital anatomic abnormality (laryngomalacia, glottic web, vocal fold paralysis). Stridor that worsens over time may indicate a growing lesion, such as a vallecular cyst, hemangioma, subglottic cyst, or external compression from a mediastinal mass or vascular sling. Worsening stridor over time may also be due to increased physical exertion by a growing child.
Exacerbating factors should be probed. Symptoms may be positional in nature: children with laryngomalacia or obstruction from a malpositioned tongue base (i.e. from craniofacial anomalies such as Pierre-Robin sequence) often have more severe symptoms when supine, and will improve with side or prone positioning. Vascular lesions may engorge with crying or straining, leading to worsened stridor.

7. Characterizing the Problem
Birth/intubation history
Associated Findings
Apneas/Cyanotic Episodes
Voice changes
Reflux
Aspiration
A detailed perinatal history, with attention to a history of prior intubation is key in the evaluation of the stridulous child. Depending on the time that has passed from extubation to the presentation of stridor, one may suspect granuloma, vocal cord immobility, or, further on from extubation, subglottic stenosis.
Close attention to associated signs and symptoms can help define the severity of the underlying condition, as well as narrow the differential diagnosis. Episodes of cyanosis, or “apparent life threatening events” (ALTEs) are a troubling sign that should prompt immediate workup, including a cardiologic evaluation. Gastroesophageal reflux can exacerbate underlying airway anomalies, as well as cause laryngeal irritation that can present as stridor. Children with airway obstruction may also present with feeding difficulties like slow feeding, coughing, choking, and regurgitation.

8. Physical Findings Retractions, tachypnea, distress
Nature of stridor – Gives an idea for anatomic site of obstruction
Inspiratory: Supraglottic
Biphasic: Glottic/subglottic/fixed tracheal
Expiratory: Tracheobronchial
Physical examination should begin with an overall assessment of the child’s appearance. Note where the child falls on the growth curve to evaluate for poor weight gain or failure to thrive. Tell-tale craniofacial abnormalities like micrognathia, cleft palate, and macroglossia may indicate an underlying syndrome. The work of breathing can be determinied by looking at the child’s respiratory rate, use of accessory muscles, and suprasternal and/or intercostal retractions. The child’s vocal quality can be an important clue as to etiology. A hoarse or aphonic cry may indicate a vocal fold paralysis, or other anatomic abnormality at the glottic level, although children with an immobile vocal fold often have normal voices.
Both the chest and neck should be auscultated. The phase or phases of respiration in which the stridor is present often points to the level of obstruction. Stridor noted during the inspiratory phase is typically seen with supraglottic pathologies. Expiratory stridor is frequently seen in tracheal lesions, such as tracheomalacia. Stridor present during both inspiration and expiration, described as biphasic stridor, connotes a fixed obstruction at the glottic or subglottic level.

9. Children Are Not Just Little Adults!
Obligate nasal breathers
Larger tongues
Larynx is more cranial and anterior
Subglottis (cricoid) is the narrowest part of airway (vs. vocal folds in adults)
Larger occiput combined w/ relatively larger tongue can promote obstruction. May be able to pass an ETT through the cords, but hit resistance below at level of cricoid

10. Workup Options

11. Airway Films
Radiologic studies can play a useful role in the evaluation of stridulous patients. AP and lateral x-rays of the chest and neck may identify subglottic or tracheal narrowing, or the presence of an aspirated or swallowed foreign body. CT scans of the neck and chest are used in the workup of patients with vascular slings to identify the nature of the vascular anomaly. Advanced reformatting of these CT images, such as 3-D reconstructions of the airway may be helpful in documenting the length of a narrowed tracheal segment. The barium esophagram may also demonstrate compression by a vascular ring, or can diagnose a tracheo-esophageal fistula. In patients for whom aspiration is a concern, a modified barium swallow may be indicated.

12. Flexible Fiberoptic Laryngoscopy
In-office
No sedation required
Gives a good view from nasal cavity to vocal folds
An indispensable tool in the otolaryngologist’s arsenal for evaluating the upper airway is the flexible fiberoptic laryngoscope. Flexible fiberoptic laryngoscopy (FFL) allows for complete evaluation of the airway from the nasal cavity, through the choanae into the nasopharynx and oropharynx, allowing an excellent view of the supraglottic and glottic larynx. This may be performed in the office, after applying a small amount of topical anesthesia to the nasal mucosa. It provides valuable information about both anatomic and functional abnormalities, as one can examine the child in an un-sedated state. One may note supralaryngeal anomalies such as prolapse of the tongue base posteriorly, vallecular cyst, or poor pharyngeal tone. An excellent view of the supraglottis and glottis is obtained. Occasionally, a view of the subglottis can be obtained, and obvious lesions (i.e. subglottic hemangioma) may be seen, though this area is best examined in the operating room with direct laryngoscopy and bronchoscopy.

13. Direct Laryngoscopy and Bronchoscopy
Direct laryngoscopy and bronchoscopy is performed in the OR on an anesthetized child. Ideally done with the child spontaneously breathing, a laryngoscope is used to visualize the larynx, and the airway may then be examined in detail from supraglottis to the mainstem bronchi, either with a ventilating bronchoscope outfitted with a 0-degree Hopkins rod, or with only the endoscope itself.
 The subglottis can be sized with uncuffed endotracheal tubes to evaluate for the presence and severity of subglottic stenosis when suspected.
Direct laryngoscopy allows for the operative management of laryngeal and tracheal lesions. Using suspension laryngoscopes allows the surgeon to have both hands free for instrumentation. A variety of tools are available for use in the airway, including cold-steel microlaryngoscopic instruments, the microdebrider, electrocautery, and the carbon dioxide laser.

14. What Do You Hear?
A. Stertor B. Inspiratory Stridor C. Biphasic Stridor D. Expiratory Stridor
Answer: A Stertor

15. What Do You Hear? A. Stertor B. Inspiratory Stridor
C. Biphasic Stridor
D. Expiratory Stridor
Answer C. Biphasic Stridor

16. What Do You Hear? A. Stertor B. Inspiratory Stridor
C. Biphasic Stridor
D. Expiratory Stridor
Answer B. Inspiratory Stridor

17. Audience Question What is the most common cause of stridor in infants?
Vocal fold paralysis
Subglottic stenosis
Hemangioma
Laryngomalacia
Answer: D. Laryngomalacia is the cause of stridor in up to 75% of infants presenting with the symptom.

18. Supraglottic Glottic Acute Chronic Subglottic/Tracheal Foreign body
Supraglottic
Glottic
Subglottic/Tracheal
Acute
Foreign body
Epiglottitis
Trauma
Laryngotracheitis (croup)
Bacterial tracheitis
Chronic
Craniofacial anomalies
Vocal fold paralysis
Subglottic stenosis
Laryngomalacia
Intubation granuloma
Subglottic cyst
Recurrent Respiratory Papillomatosis
Laryngeal web
Hemangioma
Vallecular cyst
Partial laryngeal atresia
Vascular ring/sling
Hypotonia/Neurologic dysfunction
Complete tracheal rings
Extrinsic compression
I put this very busy table here not to make you read through all the various causes for stridor, but to drive home the point that the symptom of stridor can arise from a huge variety of causes. And really, except for the child presenting with typical croup, who responds well to outpatient management, pretty much all children presenting with stridor are appropriate for referral for evaluation by a pediatric otolaryngologist. My 20 minute time limit is too short to go into each of these causes one by one, so I think it would be highest yield if we spend some time on the most commonly seen reason for stridor in infants.
Let’s start with a case presentation.

19. Case Presentation

20. HPI
2 week old male with noisy breathing since birth
Increases when feeding and when lying supine vs. sitting upright
Nursing takes a long time, with frequent need for breaks and gagging
Spits up after nearly every feed
No apneic spells or cyanosis
PMH
Full-term, uncomplicated delivery
Otherwise healthy

21. PE
Well-appearing infant in no distress
Suprasternal retractions

22. Laryngomalacia

23. Most common cause of stridor in infants (up to 75%)
Average age at presentation: 2 weeks
High-pitched, “fluttery,” inspiratory stridor worse w/ feeding, agitation, and supine position
Laryngomalacia is by far the most commonly encountered reason for stridor in the neonate.
The characteristic clinical presentation in laryngomalacia is an infant with inspiratory stridor. The stridor classically intensifies with feeding, agitation, and is positional (worse when supine versus prone). Symptoms typically begin at or shortly after birth, with an average age of presentation of 2 weeks. However, it is not uncommon for symptoms to develop even as late as several months of age.

24. Abnormal swallow study in 2/3rds
Feeding problems in ~50%
Abnormal swallow study in 2/3rds
May be abnormal even with no overt signs of aspiration
GERD in up to 2/3rds of patients – cause or consequence?
8-45% will have concomitant neurologic conditions
Incidence increases with disease severity
Obstructive sleep apnea in 60-80%
Feeding difficulties are common in children with laryngomalacia, with symptoms reported in half of cases.8 Patients are frequently reported to suffer from slow feeding, regurgitation, coughing/choking with feeds, and failure to thrive.6,9-12 Issues related to feeding and weight gain are the second most common indication for surgery. A Pittsburgh study found objective assessments of swallow function to be abnormal in two thirds of laryngomalacia patients with no complaints of dysphagia, suggesting that these issues are likely more widespread than is recognized, and should be proactively worked up in all patients.8
GERD is frequently encountered in patients with laryngomalacia. Reported in up to 66% of patients. A potential physiologic explanation is that increased negative intrathoracic pressure is generated to overcome upper airway obstruction, thus siphoning gastric contents beyond the lower esophageal sphincter. Hadfield provided evidence that surgical correction of the supraglottic obstruction objectively improved the GER as measured by 24-hour pH probe studies.17
A high proportion of patients with laryngomalacia have comorbid neurologic conditions. Reports range from 8-45% in children requiring operative management for their laryngomalacia. Incidence increases with worsening of laryngomalacia symptoms.
The incidence of OSA ranges from 62-82%. 11,12,14 The OSA typically improves with management of the laryngomalacia.

25. Mild Moderate Severe Occasional/positional stridor Persistent stridor
Constant stridor
Mild feeding symptoms
Mild retractions Slow weight gain
Deep retractions/pectus deformity Hypoxia Apneic/Cyanotic spells Failure to thrive Cor pulmonale
Patients with mild disease have occasional stridor, and mild issues with feeding, with no concerns about proper weight gain. As the airway and feeding symptoms worsen from occasional or positional to being persistent, the child may be classified as having moderate laryngomalacia. Such children may have some issues with slow weight gain, but do not meet the criteria for failure to thrive. Infants with severe laryngomalacia have constant stridor with evidence of increased work of breathing such as retractions and hypoxia. These infants may exhibit weight loss, or failure to thrive because of the increased work of breathing or difficulties with feeding. Cyanotic episodes, apneas, or “apparent life threatening” events in the setting of laryngomalacia should land a patient in the severe category. Finally, serious sequelae of airway obstruction such as pectus excavatum or cor pulmonale also mark severe disease.

26. Up to 50% can have a 2nd airway lesion
Referral to ENT generally appropriate for all kids with suspected laryngomalacia
Up to 50% can have a 2nd airway lesion
Workup
Flexible Fiberoptic Laryngoscopy (FFL)
In-office
No sedation required
Patients with laryngomalacia may have synchronous airway lesions (SAL) causing multi-level airway obstruction. Reports in the literature vary widely on the prevalence of SALs, ranging from 12% to over 50%.5,16,24-26 Patients with severe laryngomalacia may have a greater risk of a SAL than those with milder disease.24 The clinical significance of SALs is unclear. SALs in patients with mild disease increase the likelihood of the need for surgical management.26 Mancuso found that while 19% of his patients were found to have SALs, only 4.7% required additional surgical therapy.25
Flexible fiberoptic laryngoscopy (FFL) on the awake infant in the upright position allows excellent visualization of the supraglottic airway, allowing the location and degree of supraglottic obstruction to be readily visualized.

27. 3 Basic Supraglottic Abnormalities
Elongated, tubular epiglottis that collapses medially
Short aryepiglottic folds
Bulky, redundant mucosa overlying arytenoids that collapses anteriorly
The three basic abnormalities that may be present are: 1) elongated, tubular epiglottis that collapses inward and posteriorly upon inspiration, 2) foreshortened aryepiglottic folds that collapse medially, and 3) redundant mucosa overlying the arytenoid cartilages that collapse anteriorly. Most patients present with more than one type of obstruction.

28. Source: www.csurgeries.com

29. Management Watchful waiting: resolution by 18-24 months of age
Anti-reflux medication: H2-blocker vs. PPI vs. both
Surgery?
Most patients with laryngomalacia resolve their symptoms with conservative management by months of age.
Those with signs and symptoms of GERD should be treated appropriately with acid suppression therapy consisting of either a histamine receptor blocker such as ranitidine, a proton pump inhibitor, or both. Aggressive GER treatment has been linked with symptom improvement and a shortened symptom course.11

30. Audience Question
What percentage of infants with laryngomalacia have severe enough symptoms that require surgery? 5%
10%
25%
50%
Answer: Around 10% of children will present with or progress to severe symptoms requiring supraglottoplasty

31. Surgical Management Supraglottoplasty Release aryepiglottic folds
Trim redundant arytenoid tissue
+/- epiglottopexy
Approximately 10-15% of patients will present with symptoms severe enough to require surgical management. The average age at surgery ranges from 4-6 months.5,10,11
Supraglottoplasty is the current surgery of choice. The essential goals are to divide the aryepiglottic folds, trim the lateral edges of the epiglottis, and resect redundant supra-arytenoid mucosa.9 Supraglottoplasty is performed under general anesthesia, typically with the patient spontaneously breathing, although intubation may be necessary at times. There remains variation in technique with some surgeons using the CO2 laser, and others cold instrumentation. Recently, the microdebrider with the laryngeal skimmer blade has been employed to excise the aryepiglottic folds and supra-arytenoid tissue. Epiglottopexy, or fixing the epiglottis to the tongue base was utilized successfully by Fearon in 1971, and has been advocated by others to be used in select cases where the primary cause of obstruction is a retroflexed epiglottis39

33. Surgical Outcomes Post-op aspiration in 15-25% of patients
Supraglottic scarring and stenosis in 4%
Success rate 50-95%
Children with comorbidities at 7x risk of failure (especially syndromic)
Tracheostomy reserved for supraglottoplasty failures or children with severe comorbidities
Supraglottoplasty is generally successful, with reported success rates ranging from 53-95%. Supraglottoplasty failures may be due to failure to resect enough supraglottic tissue, or a patient’s comorbid condition or conditions. In the first case, revision supraglottoplasty is indicated, and has been shown to be successful. A systematic review found a relative risk of 7.14 for supraglottoplasty failure in infants with associated comorbidities compared to those without. Patients with genetic syndromes have higher failure rates than those with neurologic conditions when compared to otherwise healthy peers.
Complications from supraglottoplasty are rare. In most series, the rate is below 10%. Potential long-term complications related to supraglottoplasty include aspiration, supraglottic stenosis, laryngeal cartilage damage, airway fires, and granuloma formation. Supraglottic stenosis is reported at a rate of approximately 4%. Aspiration and/or swallowing dysfunction has been reported in 14-25% of patients after su
Tracheostomy was the mainstay of surgical management for much of the 20th century, but is now reserved for cases in which supraglottoplasty has failed, or in patients whose other conditions warrant a surgical airway.

35. THANK YOU!