Episode 163.0 – Croup

A look at one of the most common and potentially concerning upper respiratory infections in children.

May 20th, 2019 Download Leave a Comment Tags: , ,

Show Notes

Background

  • Croup is a viral infection starts in the nasal and pharyngeal mucosa but spreads to the larynx and trachea
    • Subglottic narrowing from inflammation
    • Dynamic obstruction
    • Barking cough
    • Inspiratory stridor
  • Causes:
    • Parainfluenza virus (most common)
    • Rhinovirus
    • Enterovirus
    • RSV
    • Rarely: Influenza, Measles
  • Age range: 6 months to 36 months
  • Seasonal component with high prevalence in fall and early winter
  • Differential
    • Bacterial tracheitis
    • Acute epiglottitis
    • Inhaled FB
    • Retropharyngeal abscess
    • Anaphylaxis

Presentation & Diagnosis

  • Classically a prodrome of nonspecific symptoms for 1-3 days with low grade fevers, congestion, runny nose.
  • Symptoms reach peak severity on the 4th day
  • “Steeple sign” on Xray (subglottic narrowing) present in only 50% of patients with croup
  • Assess air entry, skin color, level of consciousness, for tachypnea, if there are retractions / nasal flaring (if present at rest or with agitation) & coughing
  • “Westley Croup Score” (https://www.mdcalc.com/westley-croup-score)
    • Chest wall retractions
    • Stridor
    • Cyanosis
    • Level of consciousness
    • Air entry

Management

  • Mild Croup
    • Occasional barking cough, but no stridor at rest and mild to no retractions
    • Tx: Single dose of dex
      • Has been shown to improve severity and duration of symptoms
      • Route is not particularly important, whether it’s PO, IV or IM
      • Chosen route should aim to minimize agitation in the patient that might worsen their condition
    • May be managed at with supportive care
      • Humidifiers (NB: there isn’t good evidence supporting the use of humidifiers)
      • Antipyretics
      • PO fluids
    • Moderate Group
      • May have stridor at rest, mild-moderate retractions but no AMS and will not be in distress.
      • Tx: Dex + Racemic Epinephrine
        • Racemic epinpehrine will start to work in about 10 minutes
        • Effects last for more than an hour
      • Severe group
        • Receives the same initial therapy as the moderate group with dex and race epi
        • Pts with worrisome signs: stridor at rest, marked retraction, cyanosis and/or lethargy
        • Heliox (a combinations of 70-80% helium + 20-30% oxygen) may be attempted
          • There is limited evidence to support the role of heliox in croup,
          • NB: Pt may require higher levels of oxygen than the 20-30% mixture may provide
        • Intubation
          • Anticipate edema narrowing the airway
          • Consider starting with a tube that is 0.5 to 1 mm smaller than size typically used

Disposition:

  • Patients without stridor at rest or respiratory distress can be generally discharged from the ED
  • If epinephrine is given, patients should be monitored for 2-4 hours for reemergence of symptoms as the medication wears off

Take Home Points

  • Croup usually affects children within the age range of 6 months to 36 months with the most common cause being parainfluenza virus
  • Given the symptom overlap, we must consider more concerning diagnoses, including bacterial tracheitis, in these patients, especially if they are ill appearing or traditional therapies are ineffective
  • All patients benefit from a one-time dose of dexamethasone and, if racemic epinephrine is given, the patient should be observed for at least 3 hours
  • If intubation is required, anticipate a narrowed airway

 

Parent Article: https://coreem.net/core/croup/ by Dr. Pankow

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