Croup Notes

Croup

Introduction

• Respiratory illness: inspiratory stridor, barking cough, hoarseness.
• Inflammation of larynx and subglottic airway.
• Mostly mild, but can cause respiratory distress.

Definitions

• Viral croup: common, 6 months–3 years.
• Spasmodic croup: abrupt nighttime onset, afebrile, recurrent.
• Other types: Laryngotracheitis, Laryngotracheobronchitis, Bacterial tracheitis.

Epidemiology

• Children ≤6 years, peak at 6 months–3 years.
• More common in boys (M:F ~1.4–2:1).
• Peak incidence: Fall and early Winter.

Etiology

• Viral causes (most common):
  • Parainfluenza virus (type 1).
  • RSV, Rhinovirus, Adenovirus.
  • Influenza, SARS-CoV-2.
  • Measles (in outbreaks).
• Bacterial causes (rare):
  • Mycoplasma pneumoniae.
  • Secondary infection: S. aureus, S. pyogenes, S. pneumoniae.

Pathogenesis

• Infection spreads to larynx and trachea.
• Subglottic narrowing: Cricoid cartilage is non-expandable.
• Inflammation + exudates may lead to severe obstruction.
• Recurrent/spasmodic croup may involve noninflammatory edema.

Clinical Presentation

• Usually resolves in 24–72 hours.
• May have fever, tachypnea, retractions, restlessness.
• Starts as upper respiratory symptoms → progresses to:
  • Barking cough.
  • Stridor (inspiratory; biphasic in severe cases).
  • Hoarseness.

Evaluation

• Assess severity (Westley croup score): stridor, retractions, air entry, mental status.
• Evaluate hydration, rule out other conditions.
• Maintain calm environment.

Severity Classification

• Mild: No stridor at rest, mild or no retractions.
• Moderate: Stridor at rest, mild/moderate retractions.
• Severe: Marked retractions, agitation, fatigue, poor air entry.
• Impending respiratory failure: Fatigue, cyanosis, lethargy.

Westley Croup Severity Score

• Score ≤2: Mild
• Score 3 to 7: Moderate
• Score 8 to 11: Severe
• Score ≥12: Impending respiratory failure

Diagnosis

• Clinical: Barking cough + stridor in right age group.
• Imaging only if diagnosis uncertain: “Steeple sign” on neck X-ray = subglottic narrowing.
• Labs rarely needed unless suspecting secondary infection.

Differential Diagnosis

• Epiglottitis
• Bacterial tracheitis
• Retropharyngeal abscess
• Foreign body aspiration
• Anaphylaxis, Airway anomalies, Thermal injury

Recurrent Croup

• Consider airway abnormalities, GERD, Eosinophilic esophagitis, Atopy.
• Refer to ENT for scope and imaging.

Management Overview

• Mild croup: Supportive care + oral dexamethasone.
• Moderate to severe croup: Dexamethasone (oral/IV/IM), Nebulized epinephrine, Supportive care: hydration, antipyretics, comfort.

Home Treatment (Mild Cases)

• Encourage fluids, reduce fever.
• Mist/steam, cold air exposure (optional).
• Educate caregivers on red flags: stridor at rest, cyanosis, lethargy.

Emergency & Hospital Care

• ED: Observation 2-4 hours post-epinephrine.
• Hospital admission if poor response or worsening symptoms.
• ICU for severe cases requiring frequent epinephrine or respiratory support.

Specific Therapies

• Glucocorticoids: Dexamethasone preferred, long-acting.
• Nebulized epinephrine: Rapid relief, short duration.
• Heliox (select cases): Reduces turbulent airflow.
• Mist therapy: Comforting, minimal evidence.

Outcomes & Follow-Up

• Usually resolves in 72 hours.
• ~5-10% need hospitalization; <1% need ICU.
• Follow-up within 24 hours if treated in ED.
• Persistent/recurrent symptoms → ENT referral.