Sinusitis (Rhinosinusitis)



  • Inflammation of mucous membranes lining the paranasal sinuses and nasal passages with or without fluid collection in the sinus cavities
  • Classifications:
    • Acute: Signs and symptoms for <4 wk
    • Subacute: Signs and symptoms for 4–8 wk
    • Chronic: Signs and symptoms for >8 wk in spite of antibiotic treatment
    • Recurrent: 3 or more episodes per year


  • Acute rhinosinusitis pathophysiology:
    • Viral upper respiratory infection or allergies causes mucous membrane inflammation
    • Inflammation causes obstruction of sinus ostia, decreased mucociliary clearance, and thickening of secretions
    • Viruses are the primary cause, but 0.5–2.2% develop into bacterial infection after bacteria become trapped and multiply, resulting in suppuration
    • Nosocomial rhinosinusitis associated with nasogastric and nasotracheal tubes
    • Immunocompromised patients at higher risk for rhinosinusitis
  • Subacute and chronic rhinosinusitis pathophysiology:
    • Multifactorial, role of bacteria remains elusive
    • Allergic inflammation causing narrowed ostia and blocked drainage
    • Immune dysfunction leading to increased infectious risk
    • Impaired ciliary function leading to decreased mucous clearance
    • Odontogenic infection causing maxillary sinusitis
    • Fungus ball
    • Anatomical obstruction or polyps obstructing sinus ostia
  • Microbiology:
    • Acute rhinosinusitis:
      • Nontypable Haemophilus influenzae
      • Streptococcus pneumoniae
      • Moraxella catarrhalis
      • Staphylococcus aureus
      • Anaerobes
      • Viruses:
        • Parainfluenza
        • Adenovirus
        • Rhinovirus
        • Influenza
    • Chronic rhinosinusitis:
      • Same as acute, often polymicrobial, with increasing anaerobes and gram negatives
    • Nosocomial rhinosinusitis:
      • S. aureus
      • Streptococcal species
      • Pseudomonas
      • Klebsiella
    • Immunocompromised patients with rhinosinusitis:
      • Bacteria as above
      • Fungal pathogens
        • Aspergillus
        • Mucormycosis

Pediatric Considerations
  • Nontypable H. influenzae more common than S. pneumoniae as cause of acute bacterial rhinosinusitis in children
  • Ethmoid and maxillary sinuses present at birth
  • Sphenoid sinuses develop ∼5 yr and frontal sinuses develop ∼7 yr
  • Rhinosinusitis more common in children
  • Periorbital/orbital cellulitis is a common complication of ethmoid rhinosinusitis in children:
    • Periorbital swelling, fever, ptosis, proptosis, and painful or decreased extraocular movements

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