Description

• Acute, potentially life-threatening infraglottic bacterial infection following a primary viral infection, usually parainfluenzae or influenza viruses
• Isolated tracheitis is rare. More commonly inflammation affects surrounding tissue (1).
  • 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 incidence: 4 to 8 per 1 million (2)
• Approximately 0.1/100,000 children-years in United Kingdom (1)
• First cases described prior to 1950; resurgence of cases has been noted since 1979.
• Peak incidence in children: fall and winter
• Mean age: 5 years (2)
• 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 (MRSA) may contribute to changing epidemiology and virulence.

Etiology and Pathophysiology

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

Genetics
No known genetic predisposition

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

General Prevention

• Standard precautions, with scrupulous attention to hand washing
• Vaccination against viruses that may predispose to bacterial tracheitis
• In children with artificial airways, periodic surveillance of tracheal cultures can be helpful.

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.