Rhinosinusitis pathophysiology

Editor-In-Chief: C. Michael Gibson, M.S., M.D. [1]; Associate Editor(s)-in-Chief: Dima Nimri, M.D. [2]

Pathophysiology

Pathogenesis

Acute Rhinosinusitis

The sinuses are air-filled spaces in the skull (behind the forehead, nasal bones, cheeks, and eyes) that are lined with mucus membranes. Healthy sinuses are well-aerated and contain no bacteria. Usually, mucus is able to drain out and air is able to circulate. When the sinus openings become blocked due to swelling of the nasal mucosa, it provides a medium for an inflammatory response to ensue. Inflammation is mediated by protease in granulocytes and if the amount of protease overwhelms the amount of protease inhibitors available, tissue destruction will take place.

Chronic Rhinosinusitis

Biofilms are complex aggregates of extracellular matrix and inter-dependant microorganisms from multiple species, many of which may be difficult or impossible to isolate using standard clinical laboratory techniques. Bacteria found in biofilms may show increased antibiotic resistance when compared to free-living bacteria of the same species. It has been hypothesized that biofilm-type infections may account for many cases of antibiotic-refractory chronic sinusitis. While biofilms have been implicated in the pathogenesis of chronic sinusitis, more research needs to be done in order to understand their role in causing inflammation and disease.