INTRODUCTION – AGENTS
Causative agents of acute bacterial sinusitis are similar to those seen in other infections of the head and neck and include Streptococcus pneumoniae, Haemophilus influenzae, and Moraxella catarrhalis. Anaerobes are less frequently encountered in acute sinusitis but play a role in chronic sinusitis. Viruses can also cause acute rhinosinusitis.
Sinusitis is a common chronic condition for which patients seek physician attention in the United States. There are more than 25 million patient visits per year pertaining to sinus problems, including allergic rhinitis, viral upper respiratory infections, vasomotor rhinitis, bacterial rhinosinusitis, and nasal polyposis. Sinusitis occurs in patients of all ages but is more common in adults. Children with cystic fibrosis, however, are a unique population at much higher risk for sinus disease caused by atypical organisms, especially Pseudomonas.
The spectrum of acute to chronic sinusitis is mostly dependent on the duration of signs and symptoms. Acute sinusitis is defined as an infection that generally clears within 4 weeks. Chronic sinusitis is an infection that has been present for about 12 weeks despite treatment. Subacute sinusitis lasts longer than 4 weeks but less than 12 weeks. Recurrent acute sinusitis may be referred to as chronic (recurrent) sinusitis if a patient is afflicted with more than four infections in a year, each clearing completely (Tables 7.1 and 7.2).