1.  A child in seemingly mild distress from upper airway obstruction can deteriorate 
rapidly.

2.  Inspiratory stridor usually indicates supraglottic pathology.  An abnormal cry 
usually indicates glottic pathology.  Inspiratory and expiratory stridor indicate 
glottic, subglottic or tracheal pathology.

3.  Infants and neonates can be managed by intubation for a prolonged period of time.

4.  The incidence of tracheotomy in children is decreasing because of the increased use of intubation in epiglottis and in the control of infant’s and neonate’s airways.  The use of racemic epinephrine and steroids may also be contributing factors.

Upper airway obstruction in children can be a life threatening disorder caused by a variety of etiologies.  Important considerations in management are the rapidity of the onset, age and size of the child; along with the general history and physical examination.  The signs of distress in upper airway obstruction are often less than those found in lower airway obstruction of equal severity.  The reason for this is the small diameter of a child’s upper airway.  Poiseuille’s equation states that air flow varies with the fourth power of the radius.  In an infant with an airway diameter of five millimeters (at the cricoid), one millimeter edema will reduce the air flow by 60%.  Thus, a child in seemingly mild distress can deteriorate rapidly.  Also, the margin for error during physical examination or endoscopy is quite small.

Physical examination of the child is done immediately.  Supraclavicular, intercostal and substernal retractions are looked for along with nasal flaring.  The rate of respiration and ease of air flow is also important.  In general, children with intercostal or substernal retractions may be in severe distress even if they appear to be in no immediate danger, as they quickly tire from the respiratory effort.

The characteristic stridor is also important.  A coarse, low pitch sound similar to snoring, often indicates obstruction at the nasopharyngeal level.  A higher pitched stridor is indicative of laryngeal or trachea obstruction.  Supraglottic obstruction (e.g. laryngomalacia, epiglottis) is maximal on inspiration and exacerbated when the patient is in the prone position.  Glottic (web, stenosis, juvenile laryngeal papillomatosis) and subglottic obstruction (e.g. stenosis, hemangiomas) produces equal stridor on expiration and inspiration and is not position dependent.  Glottic pathology will cause a weak or absent cry.  An abnormal cry present for several weeks’ duration or since birth may be indicative of a vocal cord paralysis, glottic web or juvenile laryngeal papillomatosis.  A laryngoscopic examination is mandatory in these patients.

The most important elements in the patient’s history are the duration of the obstruction and age of the patient.  Otherwise, healthy patients that present with obstruction present since the neonatal period or at least for several months, usually have structural abnormalities.  They should undergo an extensive evaluation including x-ray examination, [soft tissue lateral and anterior-posterior views of the neck, chest x-ray, and barium swallow (to evaluate the presence or a vascular ring)], and endoscopy.  Febrile patients with severe obstruction that has been present for hours or days should be evaluated immediately with endoscopy.  X-ray examination plays a lesser role and the time delay in getting the test may be critical.  Also, most hospital radiological suites are not equipped to efficiently handle a respiratory arrest.  In these patients, epiglottis or laryngotracheobronchitis (LTB) are the most common etiologies of the obstruction.  

Other important elements of the history are the rapidity of onset, associated infections, change in the characteristic of stridor in relation to position, and the difficulty of breathing during sleep (snoring and sleep apnea).  Other elements of the physical examination include, the posturing of the patient, nasal drainage, drooling, nasal obstruction, pulmonary examination and oral examination.  Patients with severe upper airway obstruction, in whom epiglottis is expected, should not be agitated in any way and oral examination is contraindicated except in the controlled environment of the operating room.  Additional laboratory studies which may be necessary included blood cultures and arterial blood gases.  Cultures are done if an infectious etiology is suspected and only after the airway is controlled (e.g. while the child is asleep in the operating room.)  Blood gases are most helpful in determining the severity of the borderline chronic obstruction and in gagging the recovery of the patient.  They are of little help in the acutely obstructed child and should not be done before the airway is stabilized.

Treatment depends upon the diagnosis of the obstruction.  In general, airway control has slowly changed from tracheotomy to endotracheal intubation in the majority of severe cases.  The decrease in the incidence of tracheotomy has been attributed to the management of acute epiglottis with intubation, the use of steroids and racemic epinephrine, and the introduction of the cricoid split operation.  Also, there is a growing acceptance of prolonged intubation in the neonate.  Dankle, et al. has reported that the risks of subglottic stenosis starts to appear after 50 days of intubation.1   The overall mortality in children with a tracheotomy is 28%, with tracheotomy related deaths at 2%.2   The choice between intubation and tracheotomy for airway stabilization will vary with the institution and the individual patient.

Obstruction in the young child: Common etiologies of airway obstruction occurring immediately or soon after birth include:  choanal atresia, muconium aspiration, diaphramatic hernia, laryngeal abnormalities (paralysis, atresia, webs, cysts, clefts, subglottic hemangiomas), a vascular ring, aberrant innominate artery, tracheal abnormalities (artretic segment, web), laryngomalacia, craniofacial abnormalities (Pierre Robin Syndrome), and a small oronasopharynx.  Juvenile laryngeal papillomatosis may also present in the first few months of life and subglottic stenosis may occur after intubation in the neonatal period.  Foreign bodies are always an important consideration and croup or epiglottis may also occur within this period.  Many of these etiologies (subglottic hemangiomas, laryngomalacia, laryngeal cysts, etc.) may produce few symptoms at birth and progress over weeks or months.  Obstruction, which is severe enough to cause failure to thrive, is often progressive.  This is especially true in laryngomalacia where growth and maturation of laryngeal structures plays a vital role in the recovery of the child.

Obstruction in Older Children:   Common etiologies of airway obstruction presenting in children one year of age or older include:  Nasal obstruction (trauma, allergy, sarcomas) subglottic stenosis, epiglottitis, laryngotracheobronchitis, bacterial tracheitis, juvenile laryngeal papillomatosis, adenotonsillar hypertrophy, and foreign bodies.

Upper airway obstruction may be mistaken for lower airway obstruction.  This is most common with the subglottic and tracheal pathologies that present with expiratory and inspiratory stridor with a normal cry.  Both of these etiologies may coexist since intubation is often performed in the treatment of lower airway disease and intubation is the most common cause of subglottic stenosis.

Obstruction from Tonsils and Adenoids:  This etiology is discussed in the adenotonsillectomy section of this chapter.  Documented via sleep studies.

Obstruction from a Small Nasal Cavity or Oronasopharynx:   This etiology is often seen in the Down’s Syndrome (trisomy 21), Treacher-Collins Syndrome (mandibulofacial dysostosis), Alert’s Syndrome (acrocephalosyndactyly) and Crouzon’s Syndrome (craniofacial dysostosis). Adenotonsillectomy may mitigate the obstructive syndrome in selected patients.  However, the results as in the patients with the Down’s Syndrome3  are often not curative.
 
Oronasal Obstruction from Posterior Displacement of the Tongue:  This etiology is commonly seen in Pierre Robin Syndrome (micrognathia, glossoptosis, and cleft palate).  In these patients, adenotonsillectomy should not be done.  If performed, the chances that the patient will not achieve nasopharyngeal closure after palatoplasty are greatly increased.  The use of a pharyngeal flap to correct this incompetence can be associated with the recurrence of airway obstruction.  The preferred treatment of the upper airway obstruction is with a nasopharyngeal airway, proper positioning, and if conservative measures fail, tracheotomy.  Extremely poor results and frequent major complications have occurred with the tongue suspension operations and in general, they are only effective in mildly affected children.4

Laryngomalacia:  Is the most common cause of airway obstruction in children and is the collapse of the supraglottis during inspiration.5    Laryngomalacia is usually a benign condition presenting soon after birth with resolution in the majority of cases by age two.  The stridor often worsens up to nine months of age before subsidence occurs.  Despite the usual benign course, deaths have been reported.  Pectus exacavtum is commonly found6  and resolution of this deformity has occurred with relief of the airway obstruction.  Feeding difficulties are common and if left untreated, the child may develop failure to thrive.  Gastroesophageal reflux has been reported in up to 80% of the patients7  and severe respiratory compromise with development of cor pulmonale can occur.  A recent study8  has shown synchronous airway lesions in up to 27% of infants with laryngomalacia.  Associated abnormalities included subglottic stenosis, tracheomalacia and vocal cord paralysis.  We agree with Zalzal et. al. (1987) that a pre-operative evaluation of the airway should include soft tissue airway films and a chest x-ray.  Routine bronchoscopy should also be considered and is mandatory if resection of the obstructing supraglottic tissue does not completely relieve the respiratory symptoms during the operation.

The exact cause of supraglottic laryngomalacia is unknown.  However, two theories have been advanced to explain the pathophysiology of this condition.  The first proposes that the structures of the supraglottis are less mature and thus, lack the proper support to maintain the supraglottic airway.  The second proposes the loss of extralaryngeal support of the fibromuscular structures that attach to the supraglottis.  If surgical intervention is indicated, treatment involves the excision of redundant supraglottic tissue.9

Epiglottis:  This disorder can occur at any age, but is more commonly seen with the introduction of the flu vaccine (1994).  It is most commonly seen in children between the ages of 2 and 8 years.  In the pediatric age group, it is always caused by Hemophilus Influenza Type B.  The onset and progression are rapid with symptoms often being present for a few hours or up to one day.  The child is usually toxic and sitting in the upright position.  The stridor is Inspiratory and the patient can often not swallow without drooling being present.  Coughing is usually absent and the voice is not hoarse.  Retractions are usually not present.  They are very late signs, and their presence signifies an impending respiratory arrest and a difficult intubation.  Hospitalization with airway control is the standard with no place for watchful waiting.  The management of this disorder is a team effort with airway control taking place in the operating room under the direction of an experienced surgeon and anesthesiologist.  In institutions where in-house personnel can perform reintubation on a 24 hour basis, intubation is usually used to treat this disorder.  Blood gasses are of little help and blood cultures should be drawn in the operating room once the airway is stabilized.  Eighty percent of children are blood culture positive and will require ten days of antibiotic therapy (usually with a second generation cephalosporin, e.g. cefuroxime), and hydration is also desirable.  The use of racemic epinephrine to temporize is contraindicated.  The illness usually subsides in 24 to 48 hours after antibiotic therapy is started.  Extubation can be performed at 36 to 48 hours, once an air leak around the tube develops.  It is prudent to perform a second endoscopy at the bedside to evaluate the epiglottis before extubation takes place.  Recurrence of this illness is rare.

Croup (Laryngotracheobronchitis):  This disorder usually presents in children less than 3 years of age.  The peak incidence is in the late spring and fall, and the etiology is viral.  The onset and progression of the symptoms are slow.  There is usually a prodrome of a viral URI and symptoms usually have existed from 12 hours to several days.  Because the infection involves the supraglottic area, the stridor is both inspiratory and expiratory, a barking cough is often present and the voice is often hoarse.  The child is usually not toxic and when lying down does not drool or have difficulty swallowing.  Retractions are common and respiratory arrest is rare.  Up to 10% of children presenting with croup will require hospitalization and only 3% of those hospitalized will require an artificial airway.  In children less than one year of age, hospitalization should be considered due to their small airway and the compromising effects that even a small amount of edema will have on it.  The treatment consists of hydration, racemic epinephrine and cool mist.  The use of steroids is controversial in this disorder and is usually reserved for severe cases in an attempt to prevent an impending intubation or tracheotomy.  Most children that require an artificial airway are treated with intubation for a period of two to five days.  However, there are risks of subglottic stenosis in the narrowed inflamed subglottic area.  The tube’s presence is often required for a longer period of time.  Resolution of laryngotracheobronchitis is slow, occurring over two to five days and up to 5% of patients may have recurrence of this disease.  

Spasmodic Croup:  This occurs without a prodrome.  The child awakens with a barking cough, hoarseness, and inspiratory stridor.  Cool mist (or the night air while traveling to the emergency room) is often curative with rapid resolution of the symptoms, which may recur over the next few nights.  Unlike epiglottis, resolution usually takes place by the time the child reaches the emergency room.

Bacterial Tracheitis (pseudomembranous croup):  This is a rare disorder which presents similar to that of laryngotracheobronchitis.  The children are usually treated for LTB and have poor response to therapy.  The development of high fever and leukocytosis warrants visualization to the upper airway in the operating room.  Up to 25% of these children have had a sudden respiratory arrest.  The etiologic agent is usually Staphylococcus aureus.  Treatment consists of parenteral antibiotics (e.g. cefuroxime and oxacillin), humidification to prevent crusting, and bronchoscopy to remove the obstructive membranous exudate.  Artificial airway management is mandatory for airway control and pulmonary toilet.  The length of incubation can be up to 3 weeks and the resolution of this disorder is protracted.  Tracheotomy should be considered since the tracheotomy tube will bypass below the inflamed subglottic area and is less likely to become plugged with the thick secretions (due to the tube’s shorter length).  Also, a tube with an inner cannula (e.g. Jackson)  should be used in the immediate postoperative period.  If obstruction occurs, the changing of the inner cannula will often relieve it.  If this fails, changing the entire tracheotomy tube should be done.  In the immediate postoperative period, tracheal stay sutures will allow reinsertion.  In case of an extreme emergency, reintubation can always be done with an endotracheal tube.  After four to five days, the surgeon routinely changes the tracheotomy tube and a well established tract is usually present.  After this, the support medical personnel can easily change the tube.

Juvenile Laryngeal Papillomatosis (JLP):  Airway obstruction in this disorder is caused by masses of papillomata involving the respiratory tract.10   The peak incidence of presentation is before six months of age, although it is not uncommon for patients to develop symptoms after age five.  Symptoms include stridor, usually inspiratory and expiratory, and an abnormal cry, from involvement of the vocal cords with papillomata.  The papillomata are usually laryngeal but involvement of the oral cavity and trachea is not uncommon.  Rarely, frank pulmonary lesions may form.  The disorder is most likely viral (papovavirus) and there is an association with vaginal condylomata in the mother and JLP in the child.  The patient is not contagious.  The treatment consists of surgical excision.  This is most commonly done with the CO2 laser.  Repeated excisions are the rule with requiring over 100 excisions, always at a time of compromised airway.  If at all possible, tracheotomy is avoided.  Its use is associated with the spread of the papilloma to the tracheotomy site and lower respiratory tree.  In severe cases requiring frequent excisions (every month), interferon therapy may be tried.  Clinical trials have had conflicting results regarding the effectiveness of interferon and the different dosages used.  Toxicity from this treatment does exit and is manifested by suppression of the white cell count.  Laryngeal papillomatosis may spontaneously resolve at puberty.  New treatment is used with Indol 3 Carinol, Methotrexate, and Acyclovir (1995).

Laryngeal Cysts, Webs, and Hemangiomas:  Laryngeal cysts are usually aspirated in the neonatal period and marsupialized in older children and adults.  Webs are excised using a variety of techniques depending upon their thickness and length, and tracheotomy may be necessary during the treatment.  Subglottic hemangiomas are progressive in the neonatal period with the majority reaching full size by three months of age.  They may slowly involute over a one to two year period.  Laser excision may be curative and tracheotomy may be necessary.

Subglottic Stenosis:  The most common cause of subglottic stenosis is from long-term intubation.  Confusion with lower respiratory obstruction is common.  A “pseudoasthma syndrome” exists where a child presents with recurring respiratory distress characterized by high pitched inspiratory and expiratory airway sounds.  The symptoms are relieved by short-term intubation during which time asthma medications are administered.  Immediately after discharge, the child has little problems.  However, distress recurs in a few days to weeks.  In this syndrome, the relief of the airway distress is from the dilatation of a subglottic stenotic area by the endotracheal tube.  Subglottic stenosis should be considered in any child with recurrent respiratory distress that has been intubated.

Repeated extubation failures in the young child can often be treated with a cricoid split.11   Severe subglottic stenosis in the older child can often be treated successfully with a cartilage interposition graft or laryngotracheoplasty.

Foreign Bodies:  All foreign bodies in the airway should be removed immediately.  In children, esophageal foreign bodies can present with airway obstruction.  The soft tracheoesophageal wall bulging into the trachea causes this.  Also, foreign bodies are often multiple and once one foreign body is found, others should be searched for.  They may be radio-opaque such as coins and screws, or non-opaque as with foods or plastic toy parts.  When bronchial, they may be completely obstructing, causing atelectasis and mediastinal shift or non-obstructive (ball valving), causing emphysema and paradoxical mediastinal shift.  Both airway and esophageal foreign bodies if not promptly removed can cause erosion of the viscera with consequential neck or mediastianal abscess, or tracheoesophageal fistula.

References:

1.  Dankle, S.K., Scheller, D.S., and McClead, R.E.  Risk Factors for Neonatal Acquired Subglottic Stenosis.  Annals of Otology, Rhinology, Laryngology.  95:1986:626-630.

2.  Wetmore, R.F., et al.  Pediatric Tracheostomy.  Annals of Otology, Rhinology and 
Laryngology.  91:628-640, 1982.

3.  Kavanaugh, K.T., Kahane, J., and Kordan, B.  Risks and Benefits of Adenotonsillectomy in the Down Syndrome.  Journal of Mental Deficiency.  91(1):  22-29, 1986.

4.  Paradise and Bluestone, C.  In Pediatric Otolaryngology.

5.  Kavanaugh, K.T., and Babin, R.W.  Endoscopic Surgical Management for 
Laryngomalacia: A Case Report and Review of the Literature.  In press.  Annals of Otology, Rhinology, Laryngology.  Feb. 1987.

6.  Holinger, P.H.  Clinical Aspects of Congenital Anomalies of the Larynx, Trachea, 
Bronchi, and Esophagus.  The Journal of Laryngology and Otology.  75:1-44, 1961.

7.  Belmont, J.R., Grundfast, K.  Congenital Laryngeal Stridor (Laryngomalacia):  Etiologic Facots and Associated Disorders.  Annals of Otology, Rhinology, and Laryngology. 1984;  93:430-7.

8.  Gonzalez, C., Reilly, J.S., and Bluestone, C.K.   Synchronous Airway Lesions in Infancy.  Annals of Otology, Rhinology, and Laryngology.  1987; 96:77-80.

9.  Zalzal, G.H., Anon, J.B., and Cotton, R.T.   Epiglottoplasty for the Treatment of Laryngomalacia.  Annals of Otology, Rhinology and Laryngology.  1987; 96:72-26.

10.  Cohen, S.R., Geller, K.A., Seltzer, S., and Thompson, J.W.  Papilloma of the Larynx and Tracheobronchial Tree in Children:  A Retrospective Study.  Annals of Otology, Rhinology, and Laryngology.  89;1980:497-503.

11.  Grundfast, K.M., Coffman, A.C., and Milmoe, G.  Anterior Cricoid Split:  A “Simple Surgical Procedure and a Potentially Complicated Care Problem.  Annals of Otology, 
Rhinology, and Laryngology.  94-445-449, 1985.