Sinusitis

Sinusitis is an inflammation of the paranasal sinuses, which may or may not be as a result of infection, from bacterial, fungal, viral, allergic or autoimmune issues. Newer classifications of sinusitis refer to it as rhinosinusitis, taking into account the thought that inflammation of the sinuses cannot occur without some inflammation of the nose as well (rhinitis).

By location

There are several paired paranasal sinuses, including the frontal, ethmoid, maxillary and sphenoid sinuses. The ethmoid sinuses can also be further broken down into anterior and posterior, the division of which is defined as the basal lamella of the middle turbinate. In addition to the acuity of disease, discussed below, sinusitis can be classified by the sinus cavity which it affects:

• Maxillary sinusitis - can cause pain or pressure in the maxillary (cheek) area (e.g., toothache, headache)
• Frontal sinusitis - can cause pain or pressure in the frontal sinus cavity (located behind/above eyes), headache
• Ethmoid sinusitis - can cause pain or pressure pain between/behind eyes, headache
• Sphenoid sinusitis - can cause pain or pressure behind the eyes, but often refers to the vertex of the head

Recent theories of sinusitis indicate that it often occurs as part of a spectrum of diseases that affect the respiratory tract (i.e., the "one airway" theory) and is often linked to asthma. All forms of sinusitis may either result in, or be a part of, a generalized inflammation of the airway so other airway symptoms such as cough may be associated with it.

By duration

Sinusitis can be acute (going on less than four weeks), subacute (4-12 weeks) or chronic (going on for 12 weeks or more). All three types of sinusitis have similar symptoms, and are thus often difficult to distinguish.