Microbiology and immunology of the nose and sinuses in acute rhinosinusitis

Acute rhinosinusitis (RS) is the result of a viral upper respiratory tract infection with subsequent bacterial infection of the sinuses. The 3 major bacterial organisms associated with acute maxillary sinusitis include Streptococcus pneumoniae, nontypeable Haemophilus influenzae, and Moraxella catarrhalis. The pathogenesis of sinus infection involves obstruction of the lateral wall of the nose, obstruction of the infundibula or the entrance into the maxillary sinus and anterior ethmoids, and replication of bacteria that are resident flora of the nasopharynx and their subsequent invasion of the maxillary and ethmoid sinuses. Current treatment strategies focus on the use of antimicrobials, but in the future, strategies aimed at moderating the inflammatory response from the involved bacteria may prove to be successful in eradicating the infection.