Definitions

• Acute Infectious Croup (Acute Laryngotracheobronchitis): contagious disease in otherwise healthy children
  • Often associated with respiratory illness in the family
• Acute Spasmodic Croup: most common in young children who are prone to recurrent attacks
  • Possibly precipitated by a viral respiratory infection, allergic factors, or other factors
  • Fever is usually absent
  • Symptoms usually resolve within several hours

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Epidemiology

• Peak Age: <6 y/o

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Etiology

• Adenovirus (see Adenovirus, [[Adenovirus]])
• Influenza A/B (see Influenza Virus, [[Influenza Virus]])
• Parainfluenza Virus (see Parainfluenza Virus, [[Parainfluenza Virus]])
• Measles Virus (see Measles Virus, [[Measles Virus]]): important etiology in the developing world
• Respiratory Syncytial Virus (RSV) (see Respiratory Syncytial Virus, [[Respiratory Syncytial Virus]])
• Rhinovirus (see Rhinovirus, [[Rhinovirus]])

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Physiology

• Infection of upper airway with rapid onset of glottic closure -> upper airway obstruction

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Diagnosis

• CXR: glottic/subglottic edema -> may aid in differentiation from acute epiglottitis (although radiographs are of limited accuracy)

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Clinical Manifestations

General Comments

• Symptoms are preceded by several days of an upper respiratory illness
• Symptoms are often worse at night
• A fluctuating course is typical

Otolaryngologic Manifestations

• Acute Upper Airway Obstruction (see Obstructive Lung Disease, [[Obstructive Lung Disease]])
  • Acute Respiratory Failure (see Respiratory Failure, [[Respiratory Failure]]): due to high-grade upper airway obstruction with excessive work of breathing
  • Inspiratory Stridor (see Stridor, [[Stridor]])
• Hoarseness (see Hoarseness, [[Hoarseness]])

Pulmonary Manifestations

• Brassy or Barking Cough (see Cough, [[Cough]])
• Dyspnea (see Dyspnea, [[Dyspnea]])

Other Manifestations

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Treatment

Natural Course

• A fluctuating course is typical

Supportive Care

• Humidified Oxygen/Mist Therapy

Hospitalization

• Home Management: since most children have symptoms which decrease in intensity over several days, they can be managed at home
  • However, monitoring for upper airway obstruction is crucial

Nebulized Racemic Epinephrine (see Epinephrine, [[Epinephrine]])

• Indications: used for symptomatic relief of upper airway obstruction
• Mechanism: alpha adrenergic effect is believed to cause mucosal vasoconstriction, resulting in decreased subglottic edema
• Latency: min
• Duration of Action: <2 hr
• Clinical Efficacy: has not been demonstrated to improve oxygenation

Corticosteroids (see Corticosteroids, [[Corticosteroids]])

• Indications: mild, moderate, and severe croup
  • Single-dose corticosteroids is probably indicated in any child with severe enough croup to require an emergency room or clinic visit
• Clinical Efficacy
  • Increase rate of symptomatic improvement
  • Decrease hospital length of stay
  • Decrease the rate of intubation
• Adverse Effects: single-dose corticosteroids does not have significant adverse effects

Anti-Viral Agents

• Have not been evaluated in croup

Antibiotics

• Likely have no clinical benefit

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References

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