Episode 163.0 – Croup

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 4^th 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