• Mucosal inflammation of the nose & paranasal sinuses caused by bacteria lasting >10 days for up to 4 weeks or symptoms worsening after 5-7 days
• Often preceded by a viral upper respiratory tract infection (URTI) upper respiratory tract infection (URTI), rhinitis or other conditions that impair local or systemic immune function (eg nonallergic rhinitis, dental infection, mechanical obstruction of the nose, cystic fibrosis, ciliary dysfunction, immunodeficiency that impair the sinus drainage)
• Incidence in women is higher than men

• S pneumoniae & unencapsulated strains of H influenzae cause approximately 75% of acute rhinosinusitis cases
• M catarrhalis account for 2-10% of the cases & is more common among children
• 3-7% of the cases may be due to S pyogenes & anaerobic bacteria
• S aureus & other Streptococcal sp may occasionally cause rhinosinusitis
• Rarely Gram-negative bacilli are recovered in cases of acute rhinosinusitis
• Microaerophilic & anaerobic bacteria may be identified & isolated if the acute bacterial rhinosinusitis (ARBS) is due to the extension of dental root infection to the sinus cavity

Pathophysiology

• Occurs as a complication of a viral infection
  • Can be associated with rhinitis or other conditions that obstruct the nose or impair immune function (local or systemic)

• Signs and symptoms are nonspecific and it is typically difficult to differentiate from viral upper respiratory tract infection (URTI)
• There is fever with nasal obstruction/congestion or anterior and/or posterior purulent drainage, with or without
  
  • Facial pressure/pain/fullness
  • Reduction/loss of smell
• Other signs & symptoms include fatigue, headache, ear pressure/discomfort, throat pain, halitosis, maxillary dental pain, facial swelling or periorbital edema, cough

• Most common predisposing factors to acute bacterial rhinosinusitis (ABRS) is viral upper respiratory tract infection (URTI)
• Other factors:
  
  • Presence of medical conditions (eg allergic rhinitis, cystic fibrosis, immunodeficiency, etc)
  • Irritants (eg environmental tobacco smoke, air pollution, chlorine)
  • Anatomic (eg deviated septum, adenoidal hypertrophy, immotile cilia, polyps, tumors & foreign bodies)
  • Odontogenic sources
  • Medications (eg overuse of topical decongestants, cocaine abuse)
  • Trauma (eg dental procedure, diving)