Sinusitis occurs when the sinuses become blocked. The sinus cavities create mucous on a continual basis. Under normal circumstances, mucous from the sinuses drains into the nasal passageways or into the back of the throat. When the sinus cavities are cut off from air and are unable to drain, an environment in which germs can grow and thrive is created. In most cases, especially those of acute sinusitis, the blockage is caused by excess or thick mucous. Acute sinusitis lasts 4 weeks or less. Chronic sinusitis lasts 3 months or more. Sometimes chronic sinusitis is not caused by mucous but by tissue that blocks off the sinus cavities and prevents them from draining. This might occur because:
- tissue is abnormally enlarged
- there is scar tissue in the sinuses or nasal passageways from surgery or injury
- a person has abnormal growths such as polyps
- An individual's inherited anatomy makes it difficult for the sinuses to drain
When tissue blocks the sinuses it often results in chronic sinusitis rather than acute and usually requires surgery to treat.
Structures can directly interfere with normal drainage of the sinus cavities. Also, because the back of the throat, the nose, sinuses, and ears are all connected, some conditions, for example, ear infections or fluid in the ear, can be related to sinusitis. It is not uncommon for structures such as the adenoids or turbinates to become enlarged and contribute to sinusitis and other problems.
When the adenoids become enlarged they can not only block the sinuses but often prevent the auditory tube from draining as well causing ear infections or fluid in the ear. An adenoidectomy may be necessary to resolve ear and sinus issues.
The turbinates are part of the nasal passageways and work to warm and humidify the air we breathe. They can become enlarged and may need to be surgically reduced. Some people develop an air pocket in their middle turbinate called a concha bullosa which can predispose them to sinus problems also requires surgery to repair.
My daughter has chronic sinus problems and chronic fluid in her ears, as I said earlier both are directly related. A few years ago she was innocently looking at a picture book when her nose spontaneously started to bleed. It didn't just start to bleed though, it sprayed. That was kind of strange, plus she was having symptoms of fluid in her ears again so I took her to our ENT doctor. After examination he determined that she not only had fluid in her ears but raging sinusitis. She needed sinus surgery and a new set of ventilation tubes. After her surgery the doctor told us that she had an abnormal gelatinous membrane growing in her sinuses which he thought caused the spontaneous nosebleeds. Why did she have this membrane? I don't really know, but ironically having chronic sinusitis in and of itself can result in diseased tissue and probably caused this abnormal growth which in turn lead to more sinusitis.
Nasal polyps can also contribute to the development of sinusitis. Nasal polyps are masses of tissue that grow inside of the nose and sometimes even in the sinuses. They are not cancerous and usually occur from inflammation. Some causes of inflammation are allergies or asthma, and ironically, sinusitis. Nasal polyps are usually surgically removed.
Certain types of cancer may also cause growths which block the sinuses. However, this is more rare than other types of growths.
The septum is a piece of cartilage that divides the nostrils. It's normally centered (or close to centered) but can be deviated to one side through birth defects or injuries such as a broken nose. People with a deviated septum are more likely to develop sinusitis. The maxillary sinuses are often involved. A septoplasty is a surgery where damaged portions of the septum are repaired and then the septum is realigned.
Inherited anatomical differences can make some people more prone to develop sinusitis. For example, petite facial features can cramp structures in the face and make it more difficult for the sinuses to drain. This occurs more often in children who naturally have smaller sinuses and nasal passageways. Certain birth defects or genetic syndromes that affect facial structures, for example, cleft palate and down syndrome, can also increase the risk of sinusitis.
Medscape. Chronic Sinusitis. Accessed: January 28, 2013 from http://emedicine.medscape.com/article/232791-overview
University of Maryland Medical Center. Sinusitis. Accessed: January 28, 2013 from http://www.umm.edu/patiented/articles/who_gets_sinusitis_000062_3.htm