Sinusitis (Rhinosinusitis)

Description

• 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

Etiology

• 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)

• Nontypable H. influenzae more common than S. pneumoniae as cause of acute bacterial rhinosinusitis in children
• Ethmoid and maxillary sinuses present at birth
• Frontal and sphenoid sinuses do not emerge until age 6–7 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