Sinusitis (Rhinosinusitis)

Basics

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
    - 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

There's more to see -- the rest of this topic is available only to subscribers.