Cause and Pathogenesis

Sinusitis is caused by a variety of bacteria such as streptococci, staphylococci, pneumococci and Haemophilus influenzae viruses such as the influenza and the parainfluenza virus and less commonly by fungi such as aspergillus. Sinusitis often begins after an acute respiratory infection, which very often could be viral. Less commonly it may occur after a tooth extraction or other dental procedures, or after diving or swimming in contaminated water. Sometimes sudden changes in the climate, especially the sudden movement into cold climes, can also trigger an attack. Patients with AIDS, and other immunocompromized patients are more prone to attacks of fungal sinusitis. An attack begins with the inflammation of the nasal mucous membrane. This causes an obstruction of the opening of the sinus leading eventually to secretions accumulating in the sinus with associated pain and swelling. The secretions get infected exacerbating the situation