Friday, May 16, 2014

Acute Severe Upper Airway Obstruction in Children

Author: Shane R. Sergent, DO

Upper airway obstruction (UAO) is potentially problematic in any population, but the incidence is more common in children given that they have small compliant airways. UAO in newborns is frequently from congenital abnormalities. In contrast, infants and young children have a spectrum of differentiated causes, the most common being acute infectious etiology. It is essential to recognize UAO early since increased work of breathing in these patients rapidly progresses to respiratory failure. This is because children have a decreased respiratory reserve patients. Therefore it is time critical to identify the cause and treatment.

The most common cause in children 6 month to 6 years old (peak incidence 2 years old) is croup (acute viral laryngotracheobronchitis).[1] Majority of infections are secondary to Parainfluenza viruses types 1 and 3. Clinical presentation includes hoarseness, retractions, stridor, fever, inability to tolerate oral fluids, and the characteristc seal barking cough which are due to the characteristic subglottic narrowing. An anteroposterior view radiograph of the neck will show air shadow blurring of the tracheal and subglottic narrowing, commonly known as the "steeple sign."

The severity determines management, which can be calculated using the Westley croup score (see FIGURE 1). Regardless of severity, systemic corticosteroids and cold humidified oxygen benefit all patients and are the treatment of choice. Temporary relief of airway obstruction is achieved with nebulized epinephrine (mist is ineffective).[1] In case there is no response to medical treatment, you should be prepared for endotracheal intubation with uncuffed tubes 1-2 sizes smaller than you would normally use for that age group.[1] Consider flexible bronchoscopy in atypical or non-responsive presentations. There is no definitive treatment for the viruses that cause croup.

Epiglottitis is an acute swelling (usually within hours) of the upper airway with historic peak age of 1-7 years old with most cases secondary to Haemophilus influenza type B. The trend today is much different given the widespread use of the HIB vaccination[1]; patients tend to be older, present with atypical symptoms, and often have underlying immunodeficiency or genetically abnormalities which contribute to increase susceptibly. Reported organisms which Epiglottitis include group A β-hemolytic Streptococcus pneumoniae, Klebsiella pneumoniae, Staphylococcus aureus (including methicillin-resistant strains), Haemophilus parainfluenza, Neisseria meningitidis, Candida albicans, Varicella zoster, and other viruses.[1]

Typical symptoms include drooling, dysphagia, dysphonia, dyspnea, high fever, and stridor. Unlike croup, there is an absence of cough. During the physical exam, the child is often quite toxic appearing, sitting in a characteristic “tripod” or “sniffing” position to maximize airflow space. Diagnosis is confirmed with direct epiglottis visualization. An anteroposterior view radiograph of the neck will show the "thumb sign" which is from severe epiglottis inflammation. Pathology can be visualized with ultrasonography in the longitudinal view through the thyrohyoid membrane and has been described as the "alphabet P sign"[6].

Treatment begins with airway stabilization in a controlled environment such as the OR or PICU since there is an increase risk laryngospasm and airway closure. Intubation is commonly performed with a tube 0.5-1 mm smaller than would be used normally[1]. Nasotracheal intubation (best with endoscopic) is preferred but a safer alternative is oral intubation with stylet[1]. Physician should also be prepared for emergent needle cricothyrotomy. Post-intubation cultures and board spectrum antibiotics which cover the above organisms should be started; cefotaxime or cefriaxone plus clindamycin or vancomycin.

Bacterial tracheitis is consider rarer than the above, but is three times more likely to cause respiratory distress than Croup and Epiglottis combined2. Most commonly affects children 6 months – 8 years old (average age 4-6 years old) [1]. Patients present with a serve cough, fever,
stridor, and control secretions without difficulty. Typical organisms include S. aureus, H. influenza, S. pneumonia, S. pyogenes, and Moraxella catarrhalis. Endoscopic diagnosis exhibits subglottic edema with ulcerations and psuedomembrane formation. Treatment should include possible intubation to prevent UAO and board spectrum antibiotics which include antistaphylococcal coverage until cultures provide an appropriate regiment[3]. There is rarely a response with epinephrine.

Additional causes to consider:

Infectious mononucleosis presents with tonsillar enlargement and pharyngeal swelling. Symptoms include dyspnea, sore throat, drooling, and dysphagia. Airway management may include nasopharyngeal tube, and in rarer case endotracheal intubation. Treatment is supportive care.

Retropharyngeal abscess involves bilateral lymph nodes found in the retropharyngeal tissues. These tissues atrophy after 4 years old1 and therefore this condition presents in children less than 4 years old. Symptoms include fever, odynopagia, drooling, neck stiffness, stridor, and torticollis. Organisms include S. aureus, Streptococcus species, and anaerobes. Treatment rarely needs airway protection but early IV antibiotics is vital. If intubation is warranted, given the risk of abscess rupture, orotracheal is the preferred method. Diagnosis can be made with ultrasound and CT imaging. Surgical drainage may be warranted, therefore should be considered. Beware of the aspiration pneumonia from abscess rupture, infection of adjacent structures, sepsis, and/or mediastinitis. An additional UAO infection is a peritonsillar abscess. A peritonsillar abscess is described as an erythematous bulging located at the soft palate. The uvular will deviate contralateral to infected side.

Foreign body aspiration (FBA) usually occurs in children younger than 3 years old. If the child is coughing or choking, the obstruction will usually resolve on its own. Most objects lodge in the bronchi but about 16% will lodge in either the larynx or trachea5. Intervention is indicated if child is unable to cough or speak. If child is less than 1 year old, attempt dislodgement with five back blows followed by chest compression[1]. If child is >1 year old, attempt dislodgement with five abdominal thrusts[1]. If the complete UAO is not remedied with the above, perform direct laryngoscopy and attempt removal of foreign body with Magill forceps and/or suction[1]. Immedicate supportive care should be given following removal. Consider needle cricothyrotomy if attempt is unsuccessful. Beware that an endotracheal intubation may advance the foreign body further in the airway.

Hereditary angioedema (HAE) presents with laryngeal edema in the lifetime of ~1/2 all HAE patients[1]. Common triggers in children include oral surgery and tooth extractions1. HAE occurs secondary to a deficiency of C1 esterase inhibitor (C1 EI). This results in an uninhibited complement system. Treatment options include the following (1) IV substitution of C1 EI, (2) subcutaneous icatibant (selective competitive antagonist for the bradykinin B2 receptor), ecallantide (kallikrein inhibitor), or fresh frozen plasma1. Consider α-sympathomimetics, intubation, and possible tracheostomy. Diphteria is the most life threatening cause. Early tracheostomy, anti-diphtheric serum, and injectable pencillin.

  1. Pfleger A, Eber E. Management of acute severe upper airway obstruction in children. Paediatric Respiratory Reviews 2013; 14: 70-77.
  2.  Bjornson CL, Johnson DW. Croup. Lancet 2008; 371:329. Alberta Clinical Practice Guidelines Guideline Working Group. Guidelines to the diagnosis and management of croup. Available at$File/CROUP.PDF.
  3. Hopkins A, Lahiri T, Salerno R, Heath B. Changing epidemiology of life-threatening upper airway infections: the reremergence of bacterial tracheitis. Pediatrics 2006;118:1418-21.
  4. Devlin B, Golchin K, Adair R. Paediatric airway emergencies in Northern Ireland 1990-2003. J Laryngol Otol 2007; 121:659-63.
  5. Eren S, Balci AE, Dikici B, et, Doblan M, Eren MN. Tracheobronchial foreign body aspiration in children: experience 1160 cases. Ann Trop Paediatr 2003; 23:31-7.
  6. Hung TY, Li S, Chen PS, Wu LT, Yang YJ, Tseng LM, et al. Bedside ultrasonography as a safe and effective tool to diagnose acute epiglottitis. Am J Emerg Med. 2011; 29:359. e1-3 Epub 2010 Aug 1.

Westley croup score — Each element is assigned a score, which assists in determining severity
of infection.
  • Level of consciousness: Normal, including sleep = 0; disoriented = 5
  • Cyanosis: None = 0; with agitation = 4; at rest = 5
  • Stridor: None = 0; with agitation = 1; at rest = 2
  • Air entry: Normal = 0; decreased = 1; markedly decreased = 2
  • Retractions: None = 0; mild = 1; moderate = 2; severe = 3
The total score ranges from 0 to 17.
  • Mild croup is defined by a Westley croup score of ≤2. Typically these children have a barking cough, hoarse cry, but no stridor at rest. Children with mild croup may have stridor when upset or crying (ie, agitated) and either no, or only mild, chest wall/subcostal retractions.
  • Moderate croup is defined by a Westley croup score of 3 to 7. Children with moderate croup have stridor at rest, at least mild retractions, and may have other symptoms or signs of respiratory distress, but little or no agitation.
  • Severe croup is defined by a Westley croup score of ≥8. Children with severe croup have significant stridor at rest, although stridor may decrease with worsening upper airway obstruction and decreased air entry. Retractions are severe (including in drawing of the sternum) and the child may appear anxious, agitated, or fatigued. Prompt recognition and treatment of children with severe croup are paramount.

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