– An acute or chronic inflammatory process affecting the paranasal sinuses.

Causes and Incidence

Sinusitis is caused by bacteria (streptococci, staphylococci, pneumococci, Haemophilus influenzae); viruses (rhinovirus, influenza virus, parainfluenza virus); and fungi (aspergilli, Dematiaceae, Mucoraceae, Penicillium sp.). Onset frequently occurs after an acute respiratory infection but may also be triggered by a dental procedure or gum infection, allergic rhinitis, diving or swimming episode, or sudden drop in temperature. Sinusitis may also be associated with anatomic abnormalities of the nose. Fungally induced sinusitis most often is seen in immunosuppressed individuals such as those with AIDS, leukemia, lymphoma, or multiple myeloma or in people with poorly controlled diabetes.

Disease Process

Some factor precipitates a swollen nasal mucous membrane, which obstructs the ostium of the paranasal sinus. The oxygen in the sinus is absorbed into the blood vessels in the mucous membrane and sets up a negative pressure (vacuum) in the sinus, inducing pain. If the vacuum is maintained, a transudate is formed from the mucous membrane and fills the sinus, serving as a medium for transient bacteria, viruses, or fungi. Serum and leukocytes then rush to combat the resulting infection, causing a painful positive pressure in the obstructed sinus. The mucous membrane becomes hyperemic and edematous.


Signs and symptoms include tender, swollen areas over the involved sinus; malaise and slight fever with rhinorrhea; and seropurulent or mucopurulent drainage. Pain is specific to the sinus. Maxillary sinusitis causes pain in the maxillary area, toothache, and frontal headache. Frontal sinusitis causes frontal pain and headache. Ethmoid sinusitis causes pain behind the eyes and a splitting frontal headache. Pain from sphenoid sinusitis occurs in the occipital region.

Potential Complications

Repeated sinus attacks may lead to permanent damage to the mucosal lining and a condition known as chronic suppurative sinusitis. Frontal sinusitis may lead to severe intracranial complications, including brain abscesses, which may prove fatal. Fungal sinusitis, particularly in severely immunosuppressed individuals, can be fatal.

Diagnostic Tests

Causative organism in sinus discharge

Involved sinus produces a dark shadow (a normal sinus is light)

Sinus x-rays/computed tomography
To determine extent of sinus involvement


Endoscopy to create nasal window in acute maxillary sinusitis; Caldwell-Luc procedure for chronic maxillary sinusitis; ethmoidectomy for ethmoid or sphenoid sinusitis; creation of an osteoplastic flap to drain frontal sinus; debridement of tissue in fungally induced sinusitis.

Antiinfective drugs specific to causative agent; analgesics for pain and headache; antihistamines to reduce secretions; nasal spray vasoconstrictors to open nasal passages; adrenergics for chronic sinusitis.

Irrigation and drainage of affected sinus; steam inhalation to promote drainage; hot, moist compresses to nose to relieve pain and congestion; avoidance of smoking and other nasal irritants and allergens.