Description

• Acute, potentially life-threatening infraglottic bacterial infection following a primary viral infection, usually parainfluenzae or influenza viruses:
  • Direct laryngoscopy reveals marked subglottic edema and thick mucopurulent secretions, sometimes causing pseudomembranes.
• System(s) affected: Pulmonary
• Synonym(s): Laryngotracheobronchitis; Pseudomembranous croup; Bacterial croup

Epidemiology

• Estimated annual incidence: 0.1/100,000 (1)
• 1st cases described prior to 1950; resurgence of cases has been noted since 1979
• Peak incidence in children: Fall and winter
• Predominant age: 6 months to 8 years; mean age 4 years (similar to croup)
• Infections in adolescents and adults have been reported.
• Predominant sex: Male > Female (2:1)
• Accounts for 5–14% of upper-airway obstruction in children requiring critical-care services

• Rare illness
• Most common potentially life-threatening upper airway infection in children
• Methicillin-resistant Staphylococcus aureus (MSRA) may contribute to changing epidemiology and virulence (1).

Risk Factors

• Periods of increased seasonal activity of respiratory viruses
• Reports following adenoidectomy, with chronic tracheal aspiration, with evidence of other concurrent infections, including sinusitis, otitis, pneumonia, or pharyngitis

Genetics
No known genetic predisposition

General Prevention

• Standard precautions, with scrupulous attention to handwashing, especially when caring for tracheostomy patients
• Vaccination against viruses that may predispose to bacterial tracheitis

Etiology

• S. aureus (most common pediatric cause): Consider MRSA (2)
• Haemophilus influenzae type B
• Streptococcus pyogenes group A
• Streptococcus pneumoniae
• Moraxella catarrhalis (associated with higher intubation rate; more frequent in younger children)
• Often polymicrobial

Commonly Associated Conditions

• Consider anatomic abnormalities or foreign body as well as recent pharyngeal or laryngeal surgery.
• Predisposing: Down syndrome, immunodeficiency, subglottic hemangioma, tracheoesophageal fistula repair, tracheobronchomalacia
• Viral coinfection may occur