What is sinus infection?
Inflammation of the air cavities within the passages of the nose (paranasal sinuses) is referred to as sinusitis. Sinusitis is one of the more common conditions that can afflict people throughout their lives. Sinusitis commonly occurs when environmental pollens irritate the nasal passages, such as with hay fever. Sinusitis can also result from irritants, such as chemicals or the use and/or abuse of over-the-counter nasal sprays and illegal substances that may be snorted through the nose. Sinusitis can also be caused by infection (by viruses or bacteria). This article is a review of sinus infection.
What are the paranasal sinuses?
The paranasal sinuses are air-filled cavities in the dense portions of the bones of the skull, which were formed to decrease the overall weight of the skull. These air filled cavities are formed essentially in four left and right pairs. The frontal sinuses are positioned behind the area of the forehead, while the maxillary sinuses are behind the cheeks. The sphenoid and ethmoid sinuses are found deeper in the skull behind the eyes and maxillary sinuses. The sinuses are lined by mucous secreting cells. The air gets into the sinuses through small openings in the bones that allow connection to the nasal passageways, called ostia. If any of these openings become blocked, air can't properly pass into the sinuses and likewise the mucous produced by the cells lining the sinuses can't drain out.
What causes sinus infection?
Sinus infection may be caused by anything that interferes with airflow into the sinuses and the drainage of mucous out of the sinuses. The sinus openings may be obstructed by anything which causes swelling of the tissue lining and adjacent nasal passage tissue, for example colds, allergies, and tissue irritants (OTC nasal sprays, "coke," cigarette smoke). Sinuses can also become obstructed by tumors or growths which are in the proximity of the sinus ostia. The drainage of mucous from the sinuses can be impaired by thickening of the mucous secretions, by decrease in hydration (water content) of the mucous brought on by disease (cystic fibrosis), drying medications (antihistamines), and lack of sufficient humidity in the air. The mucous producing cells have small hairlike fibers, called cilia, which move back and forth to help the mucous move out of the sinuses. These small cilia may be damaged by many irritants, especially smoke, which then prevents them from assisting the mucous from draining from the sinuses. Stagnated mucous then provides a perfect environment for bacteria and in some circumstances (i.e.: AIDS) fungus to grow in the sinus cavities.
What are the types of sinus infections?
Sinus infection may be classified in at least two ways, based on the time span of the problem (acute, subacute, or chronic ) and the type of inflammation (either infectious or noninfectious). Acute sinus infection is usually defined as being of less than 30 days duration; subacute sinus infection as being over 1 month but less than 3 months; and chronic sinus infection as being greater than 3 months duration. Infected sinusitis is usually caused by uncomplicated virus infection. Far less frequently bacterial growth causes sinus infection. Noninfectious sinusitis can be caused by irritants and allergic conditions. Subacute and chronic forms of sinus infection usually are the result of incomplete treatment of an acute sinus infection.
What are the symptoms of sinus infection?
Commonly the symptoms of sinus infection are headache, facial tenderness or pain, and fever. However, as few as 25% of patients may have fever associated with acute sinus infection. Other common symptoms include cloudy, discolored nasal drainage, a feeling of nasal stuffiness, a sore throat, and a cough. Some people notice an increased sensitivity or headache when they lean forward. In allergic sinusitis other associated allergy symptoms of itching eyes and sneezing may be common.
How is sinus infection diagnosed?
Sinus infection is most often diagnosed based on a history and examination made by your doctor. Because plain x-ray studies of the sinuses may be misleading and procedures such as CT scans and MRI scans, which are much more sensitive in their ability to diagnose sinus infection, are so expensive, most cases of sinus infection are initially diagnosed and treated based on clinical findings on examination. These physical findings may include redness and swelling of the nasal passages, purulent (pus like) drainage from the nasal passages, tenderness to percussion (tapping) over the cheeks or forehead region of the sinuses, and swelling about the eyes and cheeks. If sinus infection fails to respond to the initial treatment prescribed, then more in-depth studies such as the above scans may be performed. Rhinoscopy, a procedure for directly looking in the back of the nasal passages with a small flexible fiber optic tube, may be used to directly look at the sinus openings and check for obstruction of these openings by either swelling or growths. It may sometimes be necessary to perform a needle aspiration of a sinus to confirm the diagnosis of sinus infection, and to get infected material to culture to determine what bacteria is actually causing the sinus infection. Cultures of the nasal passages are rarely helpful in determining what bacteria or fungus is causing a sinus infection.
How is sinus infection treated?
For sinusitis caused by virus infection, no antibiotic treatment is required. Frequently recommended treatments include pain and fever medications (such as acetaminophen/Tylenol) and decongestants. Bacterial infection of the sinuses is suspected when facial pain, pus nasal discharge and symptoms persist for longer than a week and are not responding to over-the-counter nasal medications. Acute sinus infection from bacteria is usually treated with antibiotic therapy aimed at treating the most common bacteria known to cause sinus infection, since it is unusual to be able to get a reliable culture without aspirating the sinuses. The five most common bacteria causing sinus infections are Streptococcus pneumoniae, Haemophilus influenzae, Moraxella catarrhalis, Staphylococcus aureus, and Streptococcus pyogenes. The antibiotics that are effective treatment for sinus infection must be able to kill these bacterial types. Amoxicillin (Amoxil) is an acceptable first antibiotic for an uncomplicated acute sinus infection. In the penicillin allergic patient, cefaclor (Ceclor), loracarbef (Lorabid), clarithromycin (Biaxin), azithromycin (Zithromax), sulfamethoxazole and trimethoprim (Bactrim, Septra) may be used as first choices. If a patient is not improving after five days of treatment with amoxicillin, the patient may be switched to one of the above drugs or amoxicillin-clavulanate (Augmentin). Generally an effective antibiotic needs to be continued for a minimum of 10-14 days. It is however not unusual to need to treat sinus infection for 14-21 days. Taking decongestants (pseudoephedrine) and mucolytics (guaifenesin) orally may be helpful in assisting drainage of sinus infection. In general, antihistamines should be avoided unless it is felt that the sinus infection is due to allergy, such as from pollens, dander, or other environmental causes. It is likely that the use of a topical nasal steroid spray will help reduce swelling in the allergic individual without the drying that is caused by using antihistamines. The treatment of chronic forms of sinus infection require longer courses of drugs such as Augmentin and may require a sinus drainage procedure. This drainage typically requires a surgical operation to open the blocked sinus under general anesthesia.
What are complications of sinus infection?
While serious complications do not occur frequently, it is possible for sinus infection to cause a direct extension of infection into the brain, creating a life threatening emergency.
Conclusions
Sinus infection, when treated in an appropriate manner early in the course of the illness, can usually be treated effectively. It is important to seek the advice and evaluation of your physician if you suspect that you have sinus infection. If you are prone to recurrent bouts of sinus infection it may be important for you to consider allergy testing to see if this is the underlying cause of your recurring problem.
Sinus Infection At A Glance
- Sinus infection is a form of inflammation of air cavities (sinusitis) caused by infection.
- Sinusitis can be caused from allergies, irritants, or infection within the sinuses.
- Sinus infection can cause pain in the face, teeth, or head.
- Infected sinusitis is usually caused by uncomplicated virus infection.
- Bacterial infection of the sinuses is suspected when facial pain, pus nasal discharge and symptoms persist for longer than a week and are not responding to over-the-counter nasal medications.
- Bacterial sinusitis is usually threated with antibiotic therapy.
