CRACKCast E168 – Pediatric Respiratory Emergencies: Upper Airway Obstruction and Infections

This episode of CRACKCast Covers Rosen’s Chapter 167, Pediatric Upper Airway Emergencies. Stridor is a very common presentation and this episode will help out with diagnosis and management.

Shownotes – PDF HERE

Rosen’s In Perspective:  

• Big categories for upper airway obstruction:
  • Infectious, congenital, foreign body (IN THE AIRWAY OR ESOPHAGUS!)
  • Congenital causes:
    • Think of progressive stridor or feeding difficulties.
  • In addition to the onset and duration of symptoms, ask about:
    • DROOLING
    • NECK STIFFNESS/TORTICOLLIS
    • EXACERBATING FACTORS
    • CHOKING EPISODES
  • Try to think out loud with the team:
    • Is this resp distress or resp failure?
      • Respiratory failure is identified by the presence of extreme distress, hypoventilation or hyperventilation, altered mental status, pale, mottled or cyanotic skin color, and/or hypotonia.
      • **stridor can be absent**
    • You should know the normal structures on a lateral soft tissue neck xray:

See Figure 167.3 in the text.

[1] What is the pathophysiology of inspiratory and expiratory stridor?

Stridor (from the Latin, stridulus, indicating creaking, whistling, or grating) is the classic sound associated with upper airway obstruction.

 Stridor is a harsh vibratory sound of variable pitch caused by partial airway obstruction or collapse and the resultant turbulent airflow through some portion of the airway, from the nose to the trachea. Stridor is described by timing in the respiratory cycle (inspiratory, expiratory, biphasic) and quality (coarse or high-pitched).

Inspiratory = pathology above the glottis

Biphasic = pathology at the glottis

Expiratory = pathology below the glottis

I before E.

(see figure 167.2 in Rosens)

[2] Provide a differential diagnosis for stridor in children (based on location: supraglottic, glottic, subglottic) list at least three in each category.

 Table 167.1: Causes of Stridor: Anatomic Location, Sound, and Quality

[3] What is the typical presentation of a retropharyngeal abscess?

“The retropharyngeal space is a potential space between the posterior pharyngeal wall and prevertebral fascia that extends from the base of the skull to the level of T2. It is rich in lymph tissue that drains the nose, pharynx, sinuses, and ears.”

An abscess may result from:

• direct trauma from a fall with an object in the mouth such as a toothbrush,
• suppuration of lymph nodes,
• contiguous spread of infection,
• hematogenous seeding.

It is usually a disease of infants and toddlers because the lymphatic chains are prominent in the young and atrophy before puberty.

Approximately 50% of pediatric cases occur in children 6 to 12 months of age, most occur before 3 years of age, and 96% of all diagnosed pediatric retropharyngeal abscesses are seen before 6 years of age.

Clinical presentation:

• Fever
• Sore throat
• Neck stiffness or nuchal rigidity
• Torticollis
• Tismus
• Neck swelling
• Drooling
• Stridor, and muffled voice.

**look for the child who has reluctance to extend their neck or look side to side**

Xray- must be done with the child’s head in EXTENSION (exactly what they want to avoid) and on INSPIRATION.

The soft tissue width should not be larger than 6 to 7 mm at C2, regardless of the patient’s age. At C6, this distance should not exceed 14 mm in children younger than 15 years and 22 mm in adults.

See Figure 167.4.

[4] Describe the management of a RPA. What are the typical pathogens?

Management depends on:

• The size of the abscess with resultant:
  • Clinical distress/toxicity of the patient
  • Degree of airway obstruction

Get help from an experienced ENT; These are difficult airways – may be distorted and at risk for rupturing!

Features that suggest abscess and require surgical intervention include:

• imaging findings of scalloping of the abscess wall,
• rim enhancement,
• and lesions larger than 2 cm.

The decision to admit and provide a trial of antibiotic therapy should be made between the emergency clinician and otolaryngology consultant.

Clindamycin and a third-generation cephalosporin are recommended antibiotic therapy. 

Pathogens:

polymicrobial, with Streptococcus and anaerobes the most commonly isolated organisms. Consider methicillin-resistant Staphylococcus aureus (MRSA) in severe infections such as jugular venous thrombosis or mediastinal extension.

[5] What the typical pathogens in epiglottis? How are these patients managed?

 Common Organisms

• Haemophilus influenza B, A, F, nontypeable)
• Strep
• Staph
• Pseudomonas
• Candida
• Non-infectious causes – thermal burns, chemical burns, allergic rxn, foreign bodies

Management:

• Stable patient:
  • “Infants and children: A stable patient who is maintaining a patent airway and adequate oxygenation should not be moved or repositioned for examination, laboratory tests, or radiography. Such patients should be carefully transported to a setting where definitive airway management can be achieved in a controlled fashion, generally the operating room.”
  • Adolescents and adults = have more real estate and rarely require airway management. They should be observed in the ICU and given IV abx.
• Unstable patient (respiratory failure):
  • Get help! (anesthesia, ENT, gensx)
  • Start with BVM and prepare for intubation
  • Have a backup plan – needle ventilation / cut to air

“Patients often remain intubated for 3 to 5 days in order for antibiotic therapy to reduce inflammation and surrounding tissue edema. A second- or third-generation cephalosporin is recommended.”

[6] Differentiate between croup and other conditions mimicking croup.

“Croup is diagnosed clinically. A 1- to 3-day prodrome of mild fever and URI symptoms is followed by a fairly abrupt onset of barky cough, hoarse voice, and high-pitched inspiratory stridor. Croup symptoms typically resolve in 4 to 7 days.”

Now that you know what croup is, let’s talk through things that can mimic it!

• Foreign body aspiration
• Bacterial tracheitis
• Epiglottitis
• Retropharyngeal abscess.

See Figure 167.10.

TABLE 167.2 (9^th Ed.) Comparison of Croup, Epiglottitis, and Bacterial Tracheitis

Notes on a few common congenital diseases:

• “Laryngomalacia is the most common cause of chronic stridor in infants and accounts for 60% to 75% of congenital laryngeal anomalies. It is a result of incomplete development of the supporting cartilage of the larynx. With inspiration, the long floppy epiglottis, arytenoids, and aryepiglottic folds are drawn into the larynx and create a partial obstruction.”
• Vocal cord paralysis is the second most common cause of chronic stridor in infants.
  • Bilateral = needs intervention
  • Unilateral = usually left-sided and related to traction on the left recurrent laryngeal nerve at birth or compression from mediastinal structures. Infants with unilateral vocal cord paralysis have a hoarse weak cry, feeding difficulties, and aspiration.
• Laryngeal webs
• Subglottic stenosis (congenital or acquired)
• Subglottic hemangiomas (look for the hemangiomas on the face) – usually peaks at 6 months
• Acquired papillomas

[7] Contrast mild, moderate, and severe croup.

Think about the patient: rest state, tachypnea, retractions, mental status changes

See Figure 167.10

Mild Croup

• Stridor at rest or only when agitated
• No tachypnea
• No retractions
• No Mental Status Changes

Moderate Croup

• Stridor at rest
• Mild tachypnea
• Mild retractions
• No mental status changes

Severe Croup

• Stridor at rest
• Respiratory distress
• Severe retractions
• ± Mental status changes present

Hypoxia is rarely seen and usually suggests severe croup or lower airways disease.

[8] What is the management of croup

Glucocorticoids!

Glucocorticoids reduce symptoms, decrease the need for aerosolized epinephrine, result in fewer readmissions to the ED, and shorter ED and hospital stays.

Oral dexamethasone in a dose as small as 0.15 mg/kg is as effective as higher doses in decreasing the duration of symptoms and hospitalization.

Most places we work give 0.6 mg/kg/dose (to a max of 15 mg PO)

“Aerosolized epinephrine, which reverses edema and relieves acute symptoms through vasoconstriction in the subglottic mucosa, should be given to children with stridor at rest. It is a temporizing measure with a quick onset of action (<10 minutes) and duration of 1 to 2 hours.

“ Patients should be observed in the ED for 2 to 3 hours after epinephrine administration to ensure that stridor and respiratory distress do not recur.

Adjuncts:

• ? heliox

If you need to intubate a sick crouper, be ready for a narrow airway (size down!) and have a good backup plan in place!

[9] Which children with croup require admission to hospital?

 Lab and imaging studies rarely change management, unless you are looking for something else!

• Complex med hx
  • Poor social support
  • Young < 6 months
• Sick
  • Resp distress/failure
  • Abnormal mental status
  • Persistent stridor at rest
  • TachC, tachyP
• Unusual – hypoxic, hyperpyrexia
• Dehydrated

See Box 167.1

[10] What is the management of an upper airway foreign body? In a 6 month old? In a 6 year old?

Partial obstruction:

• Patient is adequately maintaining oxygenation and ventilation = let them maintain a position of comfort. DON’T TOUCH EM!
• Get the room ready if the obstruction becomes complete, while waiting for the OR.
• Don’t paralyse them – because you may turn it into a complete obstruction!

Complete obstruction:

• <1 yr:
  • five back blows delivered between the shoulder blades, followed by five chest thrusts with the head held below the trunk.
    • Finger sweeps not recommended.
• >1 yr:
  • Heimlich maneuver for conscious children > 1 yr
  • CPR for unconscious children
  • If there is no chest rise with assisted ventilation with a bag-mask device, advanced airway techniques are indicated. Laryngoscopy should be performed to attempt visualization and foreign body removal with pediatric Magill forceps.
  • If foreign body cannot be visualized, it may be pushed distally into the right mainstem bronchus with an endotracheal tube to ventilate the nonobstructed portion of the lung.

Lethal obstruction:

• Jump right to advanced laryngoscopy with attempts to remove the foreign body
• If foreign body cannot be visualized, it may be pushed distally into the right mainstem bronchus with an endotracheal tube to ventilate the nonobstructed portion of the lung (consider taking the tube out to see if the foreign body became lodged in the tube – and then reinserting a new one)

 [bg_faq_end]

WiseCracks

[1] List a differential diagnosis for stridor (8) (review)

1. Epiglottitis
2. RPA
3. Bacterial tracheitis
4. Foreign body
5. Croup
6. Vocal cord paralysis/dysfunction
7. Congenital laryngo-tracheomalacia (Downs, digeorge)
8. Webs/rings/esophageal hemangiomas
9. Extra-tracheal masses (double aortic arch, anomalous arteries, mediastinal masses/cysts)

[2] List 5 Xray findings of epiglottitis

Shoot that lateral neck xray!

1. Thumbprint sign (big epiG!)
2. Thickened aryepiglottic folds
3. Lack of air in the vallecula
4. Dilated hypopharynx
5. NORMAL (70% of xrays)

See figure 167.5

[3] Which infections are associated with croup?

Parainfluenza virus accounts for 50% to 75% of cases; respiratory syncytial virus, influenza A and B viruses, and rhinovirus cause the remainder.

[4] Describe the presentation and management of suspected bacterial tracheitis?

Bacterial tracheitis is three times more likely to cause respiratory failure than epiglottis and viral croup combined. Bacterial tracheitis usually affects younger children, but may occur at any age.

Severe tracheal inflammation and production of thick purulent secretions!  

Usually have a preceding viral prodrome and croup-like illness…then present as a toxic child with high fevers and rapidly worsening stridor that fails to improve with racemic epinephrine. Symptoms may overlap with those of croup and epiglottitis.

Features that suggest bacterial tracheitis include a viral prodrome followed by acute decompensation, symptoms atypical for croup (eg, high fever, cyanosis, severe distress), poor response to usual treatment of croup (eg, steroids, aerosolized epinephrine), and inspiratory and expiratory stridor.

Labs = not helpful. Blood cultures = usually negative.

Call ENT and get them to the OR.

“Endoscopic tracheal débridement may result in significant clinical improvement and allow the child to be managed without intubation. Serial endoscopy may be needed to manage secretions. Endotracheal intubation is required in children with respiratory distress and hypoxia.”

“Patients should be admitted and receive supplemental oxygen, fluid resuscitation, and broad-spectrum antibiotics.”

Abx options:

• Anti-staph = vanco or clinda
• Cefotaxime or ceftriaxone

 [5] How do you handle the can’t intubate can’t ventilate (CICV) scenario?

Needle cricothyrotomy!

Surgical cricothyrotomy is not recommended for infants and young children younger than 6 to 10 years. The anatomy changes with growth (ie, the larynx is high and cricothyroid membrane small), and it may be difficult to locate pertinent anatomy until a child is of school age.

“A 14- to 18-gauge angiocatheter (the size of catheter does not affect the rate of turbulent gas flow) is inserted in the cricothyroid membrane and connected to a 3-mL syringe (without the plunger) to a 7-mm endotracheal tube (ETT) adaptor (or a 3.0-mm ETT connector directly to the angiocatheter).” PIZZA 73

This post was edited and uploaded by Owen Scheirer.

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Adam Thomas

CRACKCast Co-founder and newly minted FRCPC emergency physician from the University of British Columbia. Currently spending his days between a fellowship in critical care and making sure his toddler survives past age 5.

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Chris Lipp

Chris Lipp is one of the founding Fathers for CrackCast. He currently divides his time as an EM Physician in Calgary (SHC/FMC) and in Sports Medicine (Innovative Sport Medicine Calgary). His interests are in paediatrics, endurance sports, exercise as medicine, and wilderness medical education. When he isn’t outdoors with his family, he's brewing a coffee or dreaming up an adventure…..

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