Rhinosinusitis - Acute, Bacterial

Definition

Acute bacterial rhinosinusitis (ABRS) is an infection of the paranasal sinuses caused by bacteria, characterized by nasal congestion, purulent nasal discharge, facial pain/pressure, and fever, typically lasting less than 4 weeks.

Epidemiology

• Affects all age groups, most common in adults and children aged 5–15
• Often follows viral upper respiratory infections
• More common in winter and early spring
• Incidence is higher in patients with allergic rhinitis or anatomical sinus abnormalities
• Represents 0.5–2% of all viral upper respiratory infections progressing to bacterial infection

Etiology

• Most common bacterial pathogens: Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis
• Less common: Staphylococcus aureus, anaerobes, Gram-negative bacilli in specific populations
• Secondary to viral upper respiratory infection causing mucociliary dysfunction
• Anatomical obstruction of sinus ostia
• Immune deficiency or chronic comorbid conditions
• Recent dental infections (maxillary sinus involvement)

Pathophysiology

• Viral infection or obstruction impairs sinus drainage
• Stasis of mucus promotes bacterial growth
• Inflammation of sinus mucosa causing edema and congestion
• Release of inflammatory mediators causing pain and fever
• Purulent exudate accumulation within sinus cavities
• Increased nasal resistance and impaired sinus ventilation
• Resolution occurs with host immune response or antibiotic therapy