Pathophysiology

• Epithelial damage from a viral infection or mechanical trauma (endotracheal intubation, surgical procedure) occurs in the trachea at the level of the cricoid cartilage. As a result, the damaged tissue is more susceptible to bacterial superinfection.
• Mucosal damage characterized by marked subglottic edema, copious purulent secretions, and a pseudomembrane (mucosal lining, inflammatory products, and bacteria). These changes lead to marked airway obstruction.
• Toxic shock syndrome may be a consequence if the infection is associated with toxin-producing strains of Staphylococcus aureus or Streptococcus pyogenes.