Introduction
Rhinosinusitis, characterized by infl ammation of the maxillary and ethmoid sinuses, accounts for about 25
million offi ce visits annually in the United States. It is the fi fth most common reason physicians prescribe
antibiotics. For practical purposes, sinusitis and rhinosinusitis are interchangeable terms, although many
experts now prefer the latter because the nasal structures that are contiguous with the paranasal sinuses are
also invariably infl amed along with the sinuses.

Etiology and Pathogenesis
The normal sterility of the sinuses is maintained by continuous mucociliary clearance. A variety of physiologic and
anatomic abnormalities can lead to loss of patency of the sinus ostia and the ostiomeatal complex, the region of
common sinus drainage in the anterior middle meatus. This mechanism is thought to be common to the pathogenesis of most cases of bacterial sinusitis , both acute and chronic. Although viral upper respiratory infection
(URI) is the most common antecedent, allergic and vasomotor rhinitis can also predispose to bacterial sinusitis.
Anatomic factors that may play a role include deviated nasal septum and enlarged, pneumatized nasal turbinates
(concha bullosae). Nasal polyps arising in the presence of chronic inflammation in the sinuses may also lead to more
infection. Foreign bodies such as nasotracheal and nasogastric tubes are signifi cant in the hospitalized patient.
Cigarette smoking and certain intranasal drugs can impair ciliary action, predisposing to sinusitis. Any of these
conditions may increase edema at the sinus ostia or impair clearance from the sinuses. A relatively distinct pathogenetic mechanism is the occasional extension of a dental abscess into the maxillary sinuses that may spread into adjacent sinuses.
Cultures obtained by maxillary sinus puncture, as well as endoscopically directed cultures obtained from the
middle meatus, show that the most common bacterial pathogens, if present, are Streptococcus pneumoniae and
Haemophilus influenzae; however, other streptococci and Moraxella catarrhalis are sometimes isolated.
In patients with uncontrolled diabetes, neutropenia, or other immune-compromised states, pathogens such as
Aspergillus, Rhizopus (Mucor), Candida, Alternaria, Pseudomonas, Nocardia, Legionella, atypical mycobacteria, and
certain parasites are unusual but important etiologic considerations.
Nosocomial sinusitis associated with nasotracheal or nasogastric tubes is frequently polymicrobial. In
this setting, Staphylococcus aureus, enteric gram-negative bacteria, and anaerobes, particularly anaerobic streptococci and Bacteroides, may be present.

Culture studies of chronic rhinosinusitis reveal a different bacteriology. Anaerobes have been associated with
some cases of chronic rhinosinusitis, although their pathologic role is unclear. Similarly unclear is the high rate of
coagulase-negative staphylococcus as well as S. aureus frequently isolated in the presence of frank purulence. In the
setting of previous surgery, cultures reveal a greater prominence of gram-negative bacteria, including Pseudomonas
aeruginosa, in up to 30% of cases. Recent studies have suggested several different associated
mechanisms that may contribute to the development of chronic rhinosinusitis, distinguishing it from acute
disease and suggesting novel treatment modalities. Theories suggested include staphylococcal superantigen, chronic osteitis, biofilms, and an abnormal response to the presence of fungus in the nose.
Clinical Presentation
Patients with a “common cold” (viral rhinosinusitis or URI) usually have some combination of the following
symptoms: sneezing, rhinorrhea, congestion, facial pressure, postnasal drip, hyposmia or anosmia, sore throat,
cough, ear fullness, fever, and myalgia. Color of the mucus discharge is not an accurate indicator of bacterial infection.