Upper Airway Obstruction in Pediatrics
Authors:
Matthew R. Ledoux, MD, Assistant Professor, Pediatric Critical Care, East Carolina University, Brody School of Medicine, Greenville, NC.
Ronald M. Perkin, MD, MA, Professor and Chairman, Department of Pediatrics, Brody School of Medicine, East Carolina University, Greenville, NC.
Peer Reviewer:
Ghazala Q. Sharieff, MD, FACEP, FAAEM, Director of Pediatric Emergency Medicine, Palomar Pomerado Health System/California Emergency Physicians; Medical Director, Rady Children's Hospital Emergency Care Center, Assistant Clinical Professor, University of California, San Diego.
Complete upper airway obstruction is a rare complication of disease entities in the pediatric patient population; however, it needs to remain high on the differential diagnosis because it can abruptly become a life or death scenario. Respiratory compromise has long been known to be the leading cause of cardiac arrest in children.1
Etiologies range from infectious causes to noninfectious causes or hereditary angioedema. The authors review common presentations, pertinent diagnostic evaluation, and management strategies for disease processes that may cause upper airway obstruction.
The Editor
Introduction
The definition of an upper airway obstruction is narrowing of the normal airway above the level of the thoracic inlet including the upper trachea above the manubrium. Pediatric patients are at higher risk of complete obstruction and may become symptomatic with even a small amount of narrowing of their airway. Since resistance is proportional to the length of a tube, but inversely proportional to the radius to the fourth power of the tube, an obstruction that cuts the radius in half would take 16 times the pressure change to maintain the same laminar flow of air, and potentially 32 times (r5) for turbulent flow. In a very small infant, significant distress and work of breathing may occur with even the smallest of narrowing. As obstruction occurs closer to the cords and subglottic region, often the classic stridor is heard. Obstruction of the trachea at the level of the thoracic inlet would be heard as stridor or a high-pitched whistle.
A patient presenting to the emergency department in respiratory distress should be assessed quickly. This quick assessment should include an evaluation of the severity of the distress, and a quick assessment of the most likely etiology. In the case of a patient presenting with stridor or other symptoms consistent with upper airway obstruction, the differential often is divided into acute vs. chronic, and infectious vs. noninfectious causes. Infectious causes discussed in this article include croup, peritonsillar and retropharyngeal abscesses, epiglottitis, and bacterial tracheitis. Noninfectious causes include foreign body, ingestions/burns, trauma, and hereditary angioedema.
Infectious Causes
Infections, whether bacterial or viral, tend to be the most common cause of acute upper airway obstruction. Bacterial causes include diphtheria (rare and not discussed in this article), bacterial tracheitis, and epiglottitis. However, the most common infectious causes of acute upper airway obstruction are viruses. Parainfluenza accounts for approximately 75% of the cases of viral infections that cause some degree of airway obstruction, with other viruses including, influenza A and B, adenovirus, respiratory syncytial virus (RSV), and measles accounting for the other 25%.2
Croup. Epidemiology. Also known as laryngotracheitis, it most commonly affects children 6 months to 3 years of age. According to multiple studies, the incidence of croup in this age group ranges from 1.5-6%. It occurs more commonly in boys, and they are subsequently hospitalized more often than girls. In addition, hospitalizations were found to be more likely in the younger than 1 year old than the 1-4 year old age group.3
Etiology. Croup is most often caused by viral infection of the larynx and trachea. Viral infections have been found by PCR in 80% of patients with the diagnosis of croup.4 Viral infection causes edema and swelling of the subglottic region of the trachea, causing narrowing and, thus, the characteristic stridor. While many viruses have been implicated, parainfluenza type 1 is by far the most common cause; however, types 2 and 3 have also been implicated.4 Other viral causes include rhinovirus, enteroviruses, influenza A and B, coronavirus as well as human metapneumovirus.
Presentation. Croup has a typical presentation caused by limited and or turbulent air flow past the level of the subglottis where the inflammatory process is occurring. The turbulence produced causes the classic physical finding of inspiratory stridor. In addition to stridor on physical examination, the patient will often have a barky cough. A low-grade fever and coryza may be present.
Patients with croup and significant stridor often present to the emergency department with respiratory distress. Westley et al in 1978 published a clinical scoring system to determine the level of respiratory distress. It used level of consciousness, cyanosis, stridor, ausculatory findings, and retractions to give a score on the level of distress.5 This is often quoted and used when researching and publishing; however, it has little significance in clinical practice. More appropriately, the Alberta clinical practice guidelines include a useful classification based on physical findings and categorize croup into mild, moderate, and severe.6,7 (See Table 1.) This tool may be used for initial scoring as well as to assess progression of disease. The diagnosis of croup is usually made clinically, and X-rays are usually not indicated. However, if done to exclude other pathology (FB, epiglottitis), a tapering of the upper airway called "the steeple sign" is classic for croup.
Table 1. Alberta Clinical Assessment of Croup
|
Assessment of the Severity of Croup |
|
|
Mild |
Occasional barking cough No stridor at rest Mild or absence of retractions |
|
Moderate |
Frequent barking cough Audible stridor at rest Suprasternal and sternal retractions at rest No agitation or distress |
|
Severe |
Frequent barking cough Prominent inspiratory stridor Occasional expiratory stridor Marked retractions Agitation and distress |
Treatment. As with any cause of respiratory distress, the clinician must rapidly assess the ABCs and act accordingly. Initially, some humidified oxygen may be administered to the child to ensure proper oxygenation. There does not appear to be any evidence that the use of humidified air (warm or cool mist) has any role in improving symptoms.8-10 However, there is some thought that it may help with secretions and add moisture to the mucosa of the airway and make the child more comfortable. Minimizing unnecessary interventions is recommended, since an upset, angry child can make the degree of obstruction much worse.
Epinephrine has been shown by trials to improve the severity of croup in patients with significant symptoms. A Cochrane Database Review shows significant evidence that epinephrine aerosols have good effect within 30 minutes of administration and may need to be given repeatedly.11 The main side effects of tachycardia must be monitored closely, especially in young infants in whom supraventricular tachycardia can develop. If racemic epinephrine is administered, a dose of steroids should also be given.
Corticosteroid treatment is universally accepted as standard of care for even mild croup evaluated in the medical setting. A single dose given orally or IM/IV, which is 0.6 mg/kg of dexamethasone, has been shown to be effective. There is clear evidence from randomized controlled trials that glucocorticoids are beneficial; however, there is also some evidence that even lower doses of oral dexamethasone can be equally effective. A double-blind study showed no difference in oral dexamethasone at the single dose of 0.15 mg, 0.3 mg and 0.6 mg on length of hospital admission and relief of symptoms.12 Corticosteroids not only decrease the severity score at 6 hours, but decrease return visits, hospital admissions, and emergency room visits.13 There is expert opinion that multiple doses are not necessary and may increase the risk of side effects. Budesonide traditionally is used as the nebulized formulation and the dose is 2 mg in 4 mL nebulized.
Heliox (a mixture of helium and oxygen) is another modality utilized in the treatment of croup. However, a Cochrane review of heliox for croup (two randomized controlled trials) that compared heliox with 30% humidified oxygen and 100% oxygen with racemic epinephrine nebulization found no significant change in croup score among patients receiving heliox vs. the controls. From these studies, there seems to be no true benefit in the use of heliox.14 It should be noted smaller studies have shown some benefit in croup scores with heliox, but when compared to racemic epinephrine, there was no difference in the improvement in croup scores between the two treatment modalities.15
In the emergency department, a stepwise approach is often implemented depending on the degree of symptom severity. Using the Alberta Practice Guidelines for severity seen in Table 1, a clinician can divide the croup severity into mild, moderate, or severe. For mild symptoms, a dose of steroids may be adequate treatment, followed by discharge home and family education. For moderate symptoms, however, steroids with a longer observation period of up to 4 hours may be required, with admission to the hospital if improvement of symptoms does not occur. As for severe symptoms, steroids as well as nebulized epinephrine are usually required initially. Patients who present initially as severe can still be discharged if their symptoms do not return and they are monitored for a period of time. If patients have recurring severe symptoms or have a change in mental status, an admission to the pediatric intensive care unit (PICU) is most likely indicated. Algorithms much like the Alberta Clinical Practice Guidelines are helpful in guiding therapy and discharge plans.6 All patients who require multiple doses of racemic epinephrine or who have sustained stridor at rest should be hospitalized.6 (See Table 2.)
Table 2. Evidence-Based Management for Croup
|
Severity |
Symptoms |
Treatment |
Disposition |
|
* Alternative to dexamethasone, especially in children not tolerating PO, nebulized budesonide 2 mg is an option. ** For details of evidence-based management, see text. |
|||
|
Mild |
Without stridor Barky cough Retractions absent |
Dexamethasone PO/IM 0.6 mg/kg* |
Discharge home |
|
Moderate |
Frequent cough Stridor at rest Retractions Not in distress |
Dexamethasone PO/IM 0.6 mg/kg |
Absent or minimal improvement, consider admission after observation period If improved, discharge home |
|
Severe |
Frequent cough Prominent stridor Marked retractions Agitation or distress |
Dexamethasone PO/IM 0.6 mg/kg Nebulized racemic epinephrine 2.25% 0.5 mL in 2.5 mL saline; repeat as needed; monitoring HR Blow by oxygen as needed |
If not improved or reoccurrence of distress, consider PICU admission If symptoms resolve or considered mild after observation, may discharge home |
Deep Neck Infections
Peritonsillar abscess and retropharyngeal abscess are both infections of the deep tissues of the neck. They often cause significant distress and may pose the complication of obstruction and aspiration if the abscess ruptures.
Peritonsillar Abscess. Clinical Presentation. Typically, the patient presents with a history of sore throat as well as pain with swallowing. There may be a history of previous peritonsillar abscess, and parents may reveal that the child snores and has sleep apnea. Examination of the mouth and pharynx reveals an extremely tender posterior pharynx with erythema and swelling. Usually, peritonsillar abscess presents as a unilateral infection and gives the characteristic uvula deviation to the opposite side. There is also a noted fluctuance of the tonsil, but care must be taken to avoid rupture of the abscess during palpation. Bilateral peritonsillar abscess has been described in the literature but is rare.16 Bilateral abscesses may not present with uvula deviation. Another classic finding in peritonsillar abscess is trismus of the internal pterygoid muscle of the face. This has been reported in approximately two-thirds of patients.17 Additionally, on examination, enlarged submandibular lymph nodes are also often present.
Although in the majority of cases imaging is not necessary, when required, the preferred mode of imaging is the CT scan with contrast. Peritonsillar abscess should be seen as a fluid collection with ring enhancement of the peritonsillar space. If the CT scan or clinical exam is consistent with peritonsillar abscess, an ENT consult should be obtained. Sedation should not be used during the imaging if any degree of obstruction of the upper airway is present as sedation can exacerbate the respiratory distress.
Management. A peritonsillar abscess must be drained, and ENT consultation should be obtained once diagnosis is made by exam or CT. Three different modalities of drainage (needle aspiration, incision and drainage, or tonsillectomy) are available.
Some older patients may be managed as outpatients if they are well hydrated, can maintain hydration, can undergo either needle aspiration or incision and drainage, and take antimicrobial therapy by mouth. This may not be possible, however, if the patient is younger than 10 years of age and/or presents already with a degree of dehydration and pain that could not be managed at home. In this case, the patient should be admitted to the hospital for IV fluids, pain control, and parenteral antibiotics.
Parenteral antibiotics should be carefully chosen to cover the polymicrobial nature of these infections. Not only should staphylococcus and streptococcus be covered, but anaerobes as well. The choice of antibiotics can be adjusted once culture results return. Antibiotic choices can include ampicillin-sulbactam, clindamycin, and/or vancomycin.18 (See Table 3.)
Table 3. Treatment for Deep Neck Infections
|
Parenteral |
||
|
Drug |
Dose |
Frequency |
|
Ampicillin-sulbactam |
50-100mg/kg/dose |
Every 6 hours |
|
Clindamycin |
25-40 mg/kg/day |
Every 6-8 hours |
|
+/- Vancomycin |
40 mg/kg/day |
Divided every 6-8 hours |
|
or Linezolid |
10 mg/kg/dose 600 mg/dose (Children > 12 years old) |
Every 8 hours Every 12 hours |
Some practitioners favor the use of glucocorticoids. However, the evidence behind such recommendations is limited. There is one trial using glucocorticoids in patients older than 16 years and there seemed to be faster symptomatic improvement in the steroid group. However, there is limited evidence currently for the universal recommendation for steroid use.18
Retropharyngeal Abscess. Retropharyngeal abscess is an infection of the space between the pre-tracheal fascia and the alar fascia of the neck. This potential space runs from the base of the skull to the mediastinum and contains lymph nodes (the nodes of Ruvier) in young children. These lymph nodes usually atrophy during puberty, which explains why adolescents and young adults rarely have this type of infection, which most commonly occurs in children 2-4 years of age.
Presentation. As with many of the deep neck infections, patients can present with generalized sore throat, fever, and discomfort. However, the severity of retropharyngeal abscess progresses as the infection tracks down the fascial plane. Patients often presents with dysphasia and odynophagia. They may have fever and neck swelling with multiple enlarged lymph nodes of the neck. These patients can also present with respiratory distress depending on the impingement on the airway. Once symptoms develop the examiner must be careful not to worsen the level of respiratory distress by performing unnecessary procedures. Patients with retropharyngeal abscess can also present much like a patient with peritonsillar abscess or epiglottitis with changes in voice quality as well as drooling and posturing to maintain a patent airway. On examination, occasionally a unilateral swelling of the posterior pharynx may be visualized or a unilateral neck mass if the abscess has spread laterally. Regardless of the cause of their symptoms, these patients should be monitored for acute deterioration and may need to be taken to the operating room for securing of the airway.
Lateral neck radiographs can be performed; however, proper patient positioning is important. With the patient's head in full extension, the prevertebral space can be evaluated for widening. A widening of greater than 7 mm at the level of C2 and 14 mm of C6 is generally considered significant.19 Imaging of the neck may be necessary, and the gold standard for diagnosis is CT scan with IV contrast. (See Figures 1 and 2.) Baseline laboratory studies are not necessary but can be obtained, and patients with retropharyngeal abscess often present with elevated WBC. However, it is not common for bacteremia to be present.
Figure 1. Retropharyngeal Abscess
Figure 2. Retropharyngeal Abscess
A 10-month-old presented with drooling and neck swelling. A CT scan revealed a large retropharyngeal abscess measuring 1.8 cm in the anterior posterior, 6.8 cm in the lateral, and 7.5 cm in the vertical dimension (Figures 1 and 2).
Treatment. As with other deep neck infections, retropharyngeal abscess is usually a polymicrobial infection with predominant species being Staphylococcus, Streptococcus, and oral pharyngeal anaerobes. Treatment initially should be with broad-spectrum parenteral antibiotics. (See Table 3.) If retropharyngeal abscess is suspected or confirmed by CT scan, patients should be admitted for IV antibiotics, and ENT consultation for surgical drainage. Two major features that appear to predict a complicated course are patients who present with obstructive symptoms requiring intensive care admission and airway intervention and patients who have multiple sites of abscess.20 Patients presenting with obstructive symptoms did seem to present at a younger age. Therefore, younger patients should be monitored closely for worsening symptoms.
There are some success stories of antibiotic treatment alone in observational studies.21,22 However, other studies report lower success rates, especially in the setting of larger abscesses. Patients with severe illness, those who are admitted to the PICU, or those in areas with a strong proportion of methicillin resistance should be started on vancomycin.
Epiglottitis. Epiglottitis is swelling of the epiglottis and supraglottic region of the airway.
Epidemiology. The incidence of epiglottitis has changed dramatically since the institution of the HiB vaccine. Current etiolologic agents include Haemophilus type B, non-typeable, type A, and F have been cultured, as well as S. aureus and strep species.23,24
Etiology. The inflammation is most often caused by bacterial infection of the mucosa of the epiglottis, but can also be secondary to trauma or damage to the surface from a burn, ingestion, or even from graft vs. host disease in transplant patients.25 It is a severe infection that has a significant risk of mortality, especially if untreated. When the infection occurs and mucosa is invaded, the epiglottis swells and curls inferiorly and posteriorly, causing a degree of airway obstruction depending on the degree of swelling. The swelling usually spares the subglottic region, but the supraglottic region can be affected. This includes swelling of the aryepiglottic folds, aretynoids, and the uvula, as well as the epiglottis.
Presentation. It is imperative that patients with epiglottitis be recognized and treated quickly. This is complicated by the fact that because of the success of the immunization program in the United States and around the world, some clinicians that have trained since the early 1990s have not seen or taken care of a patient with epiglottitis.
Pediatric patients develop symptoms acutely and they progress fairly rapidly. Patients typically present to medical care within 12-48 hours from the onset of symptoms, with high fever (40° C), and complain of sore throat and respiratory distress. In addition, patients often have difficulty with their secretions and will resort to drooling rather than swallowing. Pediatric patients often sit in a very specific position, using their hands to lean forward with neck extended. This is called tripoding and is used to maintain airway patency and can be an ominous sign. Patients are often described by practitioners as having a "toxic" appearance. (See Table 4.)
Table 4. Prevalence of Presenting Symptoms of Epiglottitis in Pediatric Patients32
|
Symptom |
Percentage of Patients |
|
Difficulty breathing |
80 |
|
History of fever |
57 |
|
Sore throat |
50 |
|
Drooling |
38 |
|
Cough |
30 |
|
Difficulty swallowing |
26 |
While conducting the physical examination, the practitioner should make an effort not to cause any distress to the patient, which may worsen respiratory distress that can then progress to failure. In patients with severe distress and a history consistent with epiglottitis, it is prudent to defer the examination until the patient is in the appropriate setting to secure the airway if needed. Most likely this will occur in the operating room. Equipment and personnel should be readily available at all times to manage complete obstruction.
The additional work-up may include laboratory tests; however, in pediatric patients, this could clearly make the obstruction worse and agitate an already tenuous patient and should be deferred until the airway is secure. Once the airway is secure, routine labs may be obtained and should include CBC and blood cultures. Possible mucosal cultures of the epiglottis should be obtained while securing the airway.
Radiologic lateral images of the neck may be helpful in diagnosis of the stable patient with only mild distress. They are not always sensitive, but may help in the diagnosis. One study found that lateral neck radiographs were suggestive or diagnostic in 247 of the confirmed 287 cases of epiglottitis, yielding 86% sensitivity.26 The classic finding described by radiologists is the "thumb print sign." (See Figure 3.)
Figure 3. Epiglottitis
Note the thumb print sign (arrow)
Treatment. Patients with clinical findings suggestive of epiglottitis who are in respiratory distress require immediate airway intervention. This should be performed by the most skilled and experienced operator with the backup of a surgeon capable of performing an emergent tracheostomy or cricothyroidotomy. For intubation, a tube size smaller than calculated should be used. It is important to note that often bag valve mask ventilation is effective even if the vocal cords are difficult to visualize. Once the airway is secured, the patient should be monitored in the intensive care unit until the swelling has decreased and the patient is afebrile.27,28
Once the airway is secure, antibiotics should be administered. Empiric coverage should be started that will cover Haemophilus influenzae, Staphylococcus, and Streptococcus, typically a second- or third-generation cephalosporin such as cefuroxime or ceftriaxone.29 In addition, many communities are seeing an increased presence of methicillin-resistant Staphylococcus aureus, requiring addition of vancomycin to cover methicillin-resistant isolates.30
Glucocorticoids have been proposed to be of some benefit for the reduction of airway inflammation. However, there has not been a definitive study that shows benefit with the use of steroids.31,32 One study actually showed a prolonged hospital course in patients who received steroids. Some have argued that this may be because the patients treated with steroids were clinically sicker.31 The studies were retrospective in nature not allowing for uniformity in comparing the two groups. There may be theoretical value in their use, but should probably be reserved for use just prior to extubation and for a limited time, given the long-term side effects of steroids, including risk of gastrointestinal bleeding and hyperglycemia.23,26,32
Bacterial Tracheitis. Bacterial tracheitis is an infection of the soft tissues of the trachea caused by bacterial invasion of the mucosa. It is an acute process that can progress rapidly and can be a life-threatening event. Other names for bacterial tracheitis include laryngotracheobronchitis, pseudomembranous croup, or membranous croup.
Epidemiology/Etiology. Bacterial tracheitis is a rare condition, with an estimated incidence of 0.4 per 1000 pediatric admissions by one study,33 that typically occurs after a viral upper respiratory tract infection.34 It occurs most commonly in the winter months when viral upper respiratory infections (URIs) are most common. It does seem to occur in mostly healthy children, and is common in young children with a mean age of 5-6 years, but may also be seen in adolescents and adults. There also seems to be a slight male predominance.35,36 Multiple viruses have been implicated, including parainfluenza, influenza A and B, and RSV.34,37 It is believed that the preceding viral infection leads to micro-injury to the mucosa predisposing it to infection from bacterial causes. The most common bacterial isolate from tracheitis is Staphylococcus aureus; however, in multiple case reports, Moraxella catarrhalis is being reported as an increasingly common pathogen.35,37 Other isolates have included Streptococcus pneumoniae and pyogenes as well as methicillin-resistant Staphylococcus aureus.38
Presentation. Patients often present with a history of upper respiratory symptoms prior to the onset of fever, cough, and respiratory distress. Additional symptoms that have been described are sore throat, dyspnea, and hoarseness.33,35,36
On examination, patients are ill-appearing and may be described as toxic. They often have respiratory distress with obstructive airway findings, such as stridor both inspiratory and expiratory as well as retractions. Often what distinguishes patients with tracheitis is failure to respond to treatment for other causes of respiratory distress, such as croup.
Although radiographs are not required, imaging may be helpful in making the diagnosis. A lateral neck radiograph typically demonstrates narrowing of the subglottic region and possibly irregularity of the wall of the trachea.35 However, radiographs can be deferred if it will worsen the respiratory distress of the patient or in a severely distressed patient until the airway can be secured. Radiographs should be obtained portably, as the patient should not be left unattended because sudden respiratory depression can occur.
Treatment. Close monitoring for respiratory failure is imperative. A large portion of patients with tracheitis will require intubation. Although some studies report a 100% intubation rate, other studies report rates anywhere from 83-92% of patients.33,35 Intubation may be complicated by the fact that patients often have thick purulent secretions with non-adherent membranes that will obstruct the airway and make oxygenation and ventilation difficult. Often, intubation is only required for an average of 3 days while treatment and pulmonary toilet is performed.36 Patients may require repeated lavage and suctioning of the airway to ensure patency. In some cases, replacement of an occluded endotracheal tube may be required. In addition, rigid or flexible bronchoscopy may be beneficial, not only for sampling for cultures, but also for diagnostic as well as therapeutic indications.
Antibiotics should be started immediately and should be broad spectrum in nature until the culture and sensitivities can identify an organism. Most common isolates include S. aureus; however, organisms including methicillin-resistant staph as well as streptococcus group A and pneumoniae and Haemophilus influenzae may contribute to bacterial tracheitis. Regimens may include a third-generation cephalosporin in combination with vancomycin, or ampicillin-sulbactam in combination with vancomycin. Given the increasing prevalence of resistant Staphylococcus, vancomycin is recommended as empiric coverage.35
Steroids have been used in multiple retrospective reviews for the presumed benefit to airway inflammation. However, it should be noted that it has yet to be shown by retrospective analysis that their use decreases length of intubation or hospital stay.36 One multicenter retrospective review showed dexamethasone being used in 26 of the 30 patients treated with steroids; however, hydrocortisone, solumedrol, and prednisolone were also used.36 To date, there are no randomized trials showing benefit from any specific steroid or length of treatment with steroids.36
Noninfectious Causes of Obstruction
Although infections are common causes of acute airway obstruction in pediatric patients, there are other noninfectious causes that can cause significant morbidity and mortality. Common noninfectious causes include foreign body ingestion, trauma, and accidental ingestions causing chemical burns and potential for airway obstruction.
Foreign Body. Foreign bodies can cause a significant amount of airway obstruction leading to mortality and morbidity among pediatric patients. They may present relatively stable, requiring nonemergent intervention, or they may present with complete airway obstruction and full respiratory and cardiac arrest. Many organizations, including the AAP and the Centers for Disease Control and Prevention, have made efforts to increase education on preventing these accidents, which have contributed to reducing the overall incidence.
Epidemiology. It is estimated that in the year 2000, approximately 160 children younger than 14 years old died from obstruction of the airway from foreign bodies that were ingested or inhaled.39 It is estimated that for every child death from choking, 110 children are seen in emergency departments for treatment of a choking episode.
It was noted in the year 2001 that 17,537 children younger than 14 years old were treated in emergency rooms for choking-related episodes, equaling an incidence rate of 30 per 100,000 people. Rates were highest among infants younger than 1 year old, with males and females equally effected. Seventy-seven percent of these patients were younger than 3 years of age. Of note, 59% of these choking episodes occurred with food, including candy and gum, but most commonly nuts or seeds.40 Thirty-one percent of the episodes included nonfood substance such as coins, which made up 12% of the nonfood substances causing choking. The other 18% included things such as toys, marbles, balloons, paper, puzzle pieces, pen caps, tape, screws and other hardware, keys, plastic, cellophane, plants, rocks, jewelry, hair accessories, soda can tabs, and other specified nonfood items. Ten percent of the choking episodes occurred with an unknown substance or object.39
Of the patients treated in emergency departments, approximately 10.5% or 1,844 of the 17,537 children required admission or transfer to a higher level of care for their choking episode.39
Presentation. Patients can present immediately or, in many cases, can present days to weeks after the event. Patients who present immediately often have severe symptoms from the product obstructing the trachea or larynx. This, however, is fairly rare. These patients present with airway obstructive symptoms in acute respiratory distress with dyspnea and stridor and/or wheezing. Another group of patients that presents within the first 72 hours are patients who have a witnessed choking episode and an aspiration event, regardless of their current symptoms.41
Still another group of patients presents some time after having persistent, often mild symptoms, such as a persistent cough, fever, wheezing, or stridor. It has been found that patients presenting 4-7 days after the aspiration event have a complication rate of 64%, and patients presenting 30 days after the event have a complication rate of 95%.42 Complications include recurrent pneumonia, inflammation of the airway, and development of atelectasis. Any pediatric patient who presents for recurring symptoms that do not seem to improve should be considered to have a foreign body. These foreign bodies are almost always located in the distal airways of the bronchi. Patients who develop obstructive symptoms in the upper airway typically present with an acute aspiration event and in significant distress.
Treatment. The mainstay of treatment in a patient who has obstruction following the aspiration of a foreign body is to stabilize the patient. Radiographs may be beneficial to confirm the aspiration of a radiopaque object; however, in a patient who had a witnessed event and who is in respiratory distress, radiographs should not delay treatment with rigid bronchoscopy. It was reported in one study that only 11% of foreign bodies were radiopaque.43 Other findings on AP films that are suggestive of a foreign body include hyperinflation, an infiltrate distal to the foreign body, or atelectasis if the aspirated item lodges in the lower airway. If the suspected aspiration is believed to be in the upper airway, PA and lateral neck radiographs may be helpful looking for edema or swelling. Other radiographic images that may be helpful include bilateral decubitus views, forced expiratory views, and potentially fluoroscopy or CT scan. Supplemental oxygen and even intubation if the patient is in significant distress or is arresting may be required. Intubation should be reserved for severe cases of airway obstruction and should be performed, if at all possible, in the operating room. This allows for surgical intervention including cricothyroidotomy if needed. Even in the operating room, the induction of anesthesia and rigid bronchoscopy has risk. In one series, approximately 1% of patients had complications during retrieval, including laryngeal edema, bronchospasm, pneumothorax or mediastinum, cardiac arrest, airway laceration, or hypoxic brain injury.43
Although not discussed here in detail, esophageal foreign bodies can also present with respiratory symptoms, making it confusing as to the location at times of the foreign body. One single-center study reported 33% of patients presented with respiratory symptoms from esophageal foreign bodies. The most common respiratory symptom documented was cough in 21% of the patients. Additional respiratory symptoms included stridor, congestion, wheezing, and even apnea in 2% of the patients.44 Although respiratory symptoms were not the most common symptom, it was noted that the longer the foreign body was retained the more likely respiratory symptoms were to develop. This is presumed to be caused by prolonged compression on the soft-tissue structures of the adjacent trachea from the foreign body. At times these symptoms even resembled infectious causes like croup with inspiratory stridor.
Hereditary Angioedema. Hereditary angioedema (HAE) is an uncommon cause of angioedema and classically presents without the characteristic pruritus and urticaria seen in allergic causes of angioedema such as anaphylaxis. Its importance in the discussion of acute upper airway obstruction is that in the past it has had a mortality rate as high as 80% from the laryngeal edema that may occur.45
HAE is rare, is caused by mutations in the gene for C1 inhibitor, and is autosomal dominant in inheritance. It is estimated to occur in 1 in 10,000 to 50,000 people.46 HAE usually presents in pediatric patients in the teenage years or early adulthood. HAE patients present with recurrent episodes of mucosal and skin swelling. Most patients present with the non-life-threatening symptoms of HAE such as gastrointestinal or skin angioedema; however, laryngeal edema has been described as the initial presenting complaint.
While the skin and gastrointestinal symptoms are more common, the laryngeal attacks may present to the emergency department as acute epiglottitis.47 With the decline in bacterial causes of epiglottitis, etiology such as HAE should be considered, especially since traditional treatment of airway edema such as glucocorticoids, antihistamines, and epinephrine do not seem to be effective.47
Patients with laryngeal attacks only make up approximately 1% of all HAE attacks.48 Most attacks occur between the ages of 11 and 45 years of age.46 However, the importance of these attacks is that they can progress to complete airway obstruction and death. The swelling of the upper airway can include, but is not limited to, the uvula, soft palate, and the larynx. Symptoms reported at the time of a laryngeal episode include dysphagia, sensation of a lump in the throat or tightness, voice changes including hoarseness, and dyspnea.46 It should be noted as well that most of the episodes of HAE-induced laryngeal edema did not progress to obstruction. The episodes seem to develop over hours and are reported to occur at 8-12 hours after onset of symptoms. These symptoms may progress to near complete obstruction. At that time, patients often reported the feeling of suffocation and aphonia.46
Treatment. The initial mainstay of laryngeal attacks from HAE is to make sure the patient's airway is patent. In any patient who is suffering respiratory distress, it is imperative to recognize that the patient's symptoms may progress and complete obstruction may occur. Constant airway monitoring and the proper personnel to intubate and secure the airway should be at hand. Once it has been determined that the patient is maintaining his or her airway, or an airway has been established, then management and treatment of the angioedema may occur. Further treatment includes hydration, pain control, and the initiation of HAE-specific treatment. Consensus guidelines are available for management of HAE.45
Treatment includes use of C1 esterase inhibitor replacement protein (C1INHRP), a product available in the United States since 2008. Multiple studies have shown efficacy of this product for gastrointestinal as well as cutaneous episodes. It has also been shown in laryngeal episodes to resolve symptoms, usually within 30-60 minutes following a dose, as well as to decrease length of laryngeal swelling from 103 hours to 15 hours.46 It is given IV over 10 minutes.
Another treatment available in the United States is ecallantide. Ecallantide has been approved since 2009 for patients older than 16 years old. It is a recombinant kallikrein inhibitor which, in turn, blocks production of bradykinin. Bradykinin is activated in HAE and is responsible for the capillary leak seen in HAE and subsequent edema. Therefore, ecallantide will inhibit production of bradykinin. It is given as three 10-mg subcutaneous injections at different sites, for a total adult dose of 30 mg subcutaneously.49 Ecallantide does appear to be safe, with patients reporting adverse such as headache, nausea, diarrhea, and fever (4-8%). There is, however, a small risk, approximately 3%, of severe anaphylaxis. Patients receiving ecallantide should be closely monitored for signs of anaphylaxis when receiving treatment.49,50
Clinicians must be aware that fresh frozen plasma has also been used in the treatment of laryngeal edema in patients with HAE. It should only be used if the first-line treatments of C1INHRP or ecallantide are not available. Fresh frozen plasma was used prior to the FDA approval of these drugs with some presumed benefit. In theory, plasma contains C1 inhibitor that may improve symptoms and reverse the progression of laryngeal edema.51 In adults, two units of FFP, and in children 10-15 mL/kg, which may be repeated every 2-4 hours until improvement of symptoms. It should be noted that there have been only case reports using FFP, not any randomized controled trials.52
HAE should be considered in patients with laryngeal edema who are not responding to standard treatment. These patients should be managed aggressively to ensure proper airway management and prevention of sudden death. Once stable, these patients should have a complete work-up for HAE, including serum levels of C1 inhibitor protein levels and consultation with a specialist. A strong family history of angioedema may also be present in children who present with HAE.
Miscellaneous Causes of Airway Obstruction
Acute upper airway obstruction can also be caused by other conditions such as neck or facial trauma from motor vehicle accidents or other traumatic mechanism, ingestions of chemicals that cause a localized mucosal burn, or localized tumors of the airway.
One such tumor of the airway that is rare but often presents in infants is subglottic and supraglottic hemangiomas. Patients with these benign tumors present to the emergency department often with a history of multiple episodes of respiratory distress, and these tumors can cause airway obstruction.53,54 Although rare, subglottic hemangioma is the most common neoplasm of the infant airway.55 The most common physical examination finding is biphasic stridor, and approximately 50% of patients have cutaneous hemangiomas.55 A detailed history may allude to multiple episodes of croup being diagnosed in the past, without the presence of URI symptoms. Diagnosis is done by direct laryngoscopy, and MRI imaging may be of benefit. These tumors must be monitored closely due to a reported mortality rate of 30-70% of undiagnosed or proliferating tumors.56,57 Treatment ranges from conservative treatment to the use of steroids, laser therapy, and even open resection and the use of tracheostomy.55
Conclusion
A patient presenting to the emergency department in respiratory distress should be assessed quickly. In the case of a patient presenting with stridor or other symptoms consistent with upper airway obstruction, the differential often is divided into acute vs. chronic, and infectious vs. noninfectious causes. Infectious causes reviewed in this article include croup, peritonsillar and retropharyngeal abscesses, epiglottitis, and bacterial tracheitis. Noninfectious causes include foreign body, ingestions/burns, trauma, and hereditary angioedema. Prompt recognition and aggressive treatment may improve morbidity and mortality for children with these conditions.
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Complete upper airway obstruction is a rare complication of disease entities in the pediatric patient population; however, it needs to remain high on the differential diagnosis because it can abruptly become a life or death scenario. Respiratory compromise has long been known to be the leading cause of cardiac arrest in children.You have reached your article limit for the month. Subscribe now to access this article plus other member-only content.
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