Sinusitis, or inflammation of the lining of the sinuses, is one if the most common medical ailments in the United States, affecting some 31 million adults annually. The sinuses are air filled cavities within the bones of the face and skull that communicate with the nose through tiny openings. The openings allow air to enter the sinus, and the mucus that is produced by the sinus lining to exit into the nose.

Sinusitis is a condition that significantly affects the quality of life of its sufferers, causing pain, airway obstruction and discharge, alteration of smell and flavor senses and headache. Rarely, extension of the inflammation can involve the brain or eye, causing blindness, neurologic injury or even death. Sinusitis a major cause of US health care expenditures for OTC and prescription drugs, physician services and hospital care, estimated to be $3.30 billion in direct expenditures and $5.8 billion in total expenditures in 1996. This has almost certainly increased since then.


What Causes Sinusitis?
For many decades doctors thought that most cases of sinusitis in its chronic form were the result of persistent infection. However, it is now recognized that chronic rhinosinusitis, as it is better termed, exists in at least two forms. The first considers the disorder to be a systemic problem due to a malfunction of the immune system. This condition often accompanies asthma. In the second form, there are local factors that lead to recurrent or persistent sinus infections.

Many diseases are associated with chronic rhinosinusitis. However, the detection of a specific cause is often a daunting task in a particular patient. The most commonly assumed factors that perpetuate the sinusitis are allergies, bacterial infections and fungal infection or contamination. Other important factors include anatomic deformities of the nose and sinuses, malfunctions of the flow of mucus, endocrine disorders such as thyroid disease and diabetes, reduced immunity, injuries, medication effects, chemical irritation of the nasal lining and previous surgery. Although there is good reason to believe that infections and allergies play some role, it may be in form of strengthening the inflammation, rather than originating it. This concept is reinforced by the fact that appropriate and prolonged antibiotics and allergy immunotherapy do not cure the majority of cases of chronic sinusitis.

A special subset of chronic rhinosinusitis is that form accompanied by severe polyps extending into and sometimes filling the nasal cavity. Polyps represent severely swollen lining from the sinus and nasal wall that obstructs, sometimes completely, the nose and sinuses. Chronic allergic aspergillosis (a fungal overgrowth) of the sinuses as well as aspirin hypersensitivity asthma (Samter’s triad) are both associated with extensive polyps, indicating that disturbances in regulation of inflammation are capable of causing polyps. The fact that complete surgical removal of the polyps and infection often is followed by the rapid return of polyps would indicate that some sort of malfunction in the control of inflammation, rather that the mere presence of bacteria or anatomic factors, underlies the development of chronic polypoid rhinosinusitis. This is further strengthened by the complete suppression of polyp formation with high dose systemic cortisone.

How is Sinusitis Treated?
With the frequent failure of medical treatments, surgical procedures have been widely used to treat rhinosinusitis. These operations were originally invented in the nineteenth century as drainage procedures for acute, pus forming infections of the sinuses, and they were mainly used only in life threatening cases. The extension of these drainage operations to treat chronic rhinosinusitis came in the twentieth century. Their current form, called functional endoscopic sinus surgery,was spurred by technologic advances that joined improvements in endoscopic instrumentation with detailed sinus x-ray images in provided by CT scans of the sinuses. Dr. Kimmelman has performed this kind of surgery for almost 20 years. He and other leaders in the field have shown that endoscopic sinus surgery certainly does benefit chronic rhinosinusitis caused by anatomic abnormalities, isolated fungal accretions (fungus balls), injuries, dental disorders and congenital malformations. However, not all cases of chronic rhinosinusitis are completely and permanently cured on a long term basis by these procedures alone. The underlying immune mechanisms and systemic factors are unchanged by the surgical operation.

There is a growing consensus that the control of the inflammation is the prime critical element in the treatment of sinusitis. Infections from bacterial or fungal organisms, allergy and other inflammatory conditions, such as autoimmune disease, may play a role in the majority of cases.

This lack of a clear understanding of the underlying causes of chronic rhinosinusitis has hampered attempts to devise effective treatments. Indeed, the major pharmaceutical firms have not chosen to target chronic rhinosinusitis as an FDA approved market for their drugs because of their lack of proven effectiveness. Doctors have been therefore forced to use many drugs and treatments without clear scientific evidence of benefit. As a result of the presence of multiple factors, the final common pathway of inflammation is a reasonable target for treatment. Oral (pills), nasally injected (with a needle) and topical (inhaled) cortisone like medicines are the most commonly utilized anti-inflammatory drugs. Washing out the nose with various salt water solutions is used to clean out thick or crusted secretions contaminated with organisms. Topical decongestants (like Afrin™) can be used for short durations, and systemic decongestants (like Sudafed™) may be employed for longer periods with some slight benefit to drainage. Antihistamines are helpful in “drying up” allergies, but their contribution is hampered by the fact that thick, dry secretions are more likely to become colonized by bacteria, which leads to even more inflammation. Other medicines, such as Singulair™, are appealing because of their interference with known inflammatory mediators; however, since there are many other signals that sustain inflammation, these drugs have not had a major impact on chronic rhinosinusitis.

Why is Chronic Sinusitis so Hard to Treat?
Biofilm formation by microorganisms in the mucus blanket allows organisms to flaunt the efforts of the immune system and antibiotics to eliminate them. Biofilms are a state of bacterial life characterized by the formation of a starch-like barrier to protect the encased organisms, which slow down their metabolic and growth behavior as well. Most sinus infections are associated with biofilm formation.Ehrle Antiadhesion substances, such as xylitol, show promise in preventing the attachment of organisms before they can form biofilms. In the future more sophisticated drugs that stop chemical signaling (“quorum” sensing) among microbes may reduce the formation of biofilms.