Nasal sinuses are hollow, air containing cavities in the skull behind the forehead and cheeks of the face. There are four pairs of sinuses and these are referred to as the paranasal sinuses. Sinusitis occurs when one or more sinuses become infected causing inflammation of the membranes that line the sinus cavity. Sinusitis is a common problem affecting millions of people around the world.
There are four paired sinuses called paranasal sinuses. The paranasal sinuses consist of the following:
- Ethmoidal Sinuses: These are paired sinuses located in between the eyes and nasal cavity. Each sinus consists of 4 – 18 air containing cavities – the ethmoidal air cells. These sinuses are present at birth and continue to grow until adolescence. The anterior air cells open into the middle meatus and the posterior group open into the superior meatus.
- Maxillary Sinus: It is the largest of all sinuses with a volume of about 15 ml. These are paired cavities located inside the face around the area of the cheeks. This sinus is also present at birth and continues to grow afterwards. The sinus opens into the middle meatus.
- Frontal Sinus: This is the last of the sinuses to develop. These are paired cavities located inside the face around the area of the forehead. The sinuses open into the middle meatus.
- Sphenoid Sinus: These are also paired cavities located deep in the face behind the nose. Each sinus has a volume of about 7.5 ml. They open into a small recess behind the superior meatus.
Sinusitis means your sinuses are infected or inflamed. Health experts usually divide sinusitis cases into:
- Acute cases, which last for 4 weeks or less
- Subacute cases, which last 4 to 12 weeks
- Chronic cases, which last more than 12 weeks and can continue for months or even years
- Recurrent cases, which involve several acute attacks within a year
Symptoms of Sinusitis
One of the most common symptoms of sinusitis is pain, and the location depends on which sinus is affected.
- If you have a pain in your forehead over the frontal sinuses when you are touched, your frontal sinuses may be inflamed.
- If your upper jaw and teeth ache, and your cheeks become tender to the touch, you may have an infection in the maxillary sinuses.
- If you have swelling of the eyelids and tissues around your eyes, and pain between your eyes, you may have inflammation of the ethmoid sinuses that are near the tear ducts in the corner of your eyes. Ethmoid inflammation also can cause a stuffy nose, a loss of smell, and tenderness when you touch the sides of your nose.
- If you have earaches, neck pain, and deep achiness at the top of your head, you may have infection in the sphenoid sinuses, although these sinuses are less frequently affected.
Most people with sinusitis have pain or tenderness in several locations, and their symptoms usually do not clearly indicate which sinuses are inflamed.
In addition to the pain, people with sinusitis frequently have thick nasal secretions that are yellow, green, or blood-tinged. Sometimes these secretions, referred to as post-nasal drip, drain in the back of the throat and are difficult to get rid of. Also, acute and chronic sinusitis are strongly associated with nasal symptoms such as a stuffy nose, as well as with a general feeling of fullness over the entire face.
Less common symptoms of sinusitis can include:
- Decreased sense of smell
- Cough that may be more severe at night
- Sore throat
- Bad breath
On rare occasions, acute sinusitis can result in brain infection and other serious complications if left untreated.
Causes of Acute Sinusitis
Most cases of acute sinusitis start with a common cold, which is caused by a virus. Colds can inflame your sinuses and cause symptoms of sinusitis. Both the cold and the sinus inflammation usually go away without treatment within 2 weeks. If the inflammation produced by the cold leads to a bacterial infection, however, then this infection is what health experts call acute sinusitis.
The inflammation caused by the cold results in swelling of the mucous membranes (linings) of your sinuses, and this can lead to air and mucus becoming trapped behind the narrowed openings of the sinuses. When mucus stays inside your sinuses and is unable to drain into your nose, it can become the source of nutrients (material that gives nourishment) for bacteria.
Most healthy people harbor bacteria, such as Streptococcus pneumoniae and Haemophilus influenzae, in the nose and throat, and the bacteria cause no problems. But when you have a cold, you tend to sniff or to blow your nose, and these actions cause pressure changes that can send bacteria inside the sinuses. If your sinuses then stop draining properly, bacteria that may have been living harmlessly in your nose or throat can begin to multiply in your sinuses, causing acute sinusitis.
People who suffer from allergies that affect the nose (like pollen allergy, also called hay fever), as well as people who may have chronic nasal symptoms not caused by allergy, are also prone to develop episodes of acute sinusitis. The chronic nasal problems cause the nasal membranes to swell, and the sinus passages become blocked in a manner similar to that described above for the common cold. The normally harmless bacteria in the nose and throat again lead to acute sinusitis.
Rarely, fungal infections can cause acute sinusitis. Although fungi are abundant in the environment, they usually are harmless to healthy people because the human body has a natural resistance to fungus. However, in people whose immune system is not functioning properly, fungus, such as Aspergillus, can cause acute sinusitis. (Aspergillus is commonly found growing on dead leaves, stored grain, compost piles, or in other decaying vegetation.)
In general, people who have reduced immune function (such as those with primary immune deficiency disease or HIV infection) or abnormalities in mucus secretion or mucus movement (such as those with cystic fibrosis) are more likely to suffer from sinusitis.
Causes of Chronic Sinusitis
In chronic sinusitis, the membranes of both the paranasal sinuses and the nose are thickened because they are constantly inflamed. Most experts now use the term "chronic rhinosinusitis" to describe this condition, and they also recommend that the condition be divided into rhinosinusitis with or without nasal polyps. Nasal polyps are grape-like growths of the sinus membranes that protrude into the sinuses or into the nasal passages. Polyps make it even more difficult for the sinuses to drain and for air to pass through the nose.
The causes of chronic sinusitis are largely unknown. The condition often occurs in people with asthma, the majority of who have allergies. It is possible that constant exposure to inhaled allergens that are present year-round, such as house dust mites, pets, mold (a kind of fungus), and cockroaches cause chronic inflammation of the nose and the sinuses. An allergic reaction to certain fungi may be responsible for at least some cases of chronic sinusitis; this condition is called "allergic fungal sinusitis." At least half of all people with chronic rhinosinusitis do not have allergies, however.
Most health experts believe that chronic rhinosinusitis is not an infectious disease (like acute sinusitis). If you suffer frequent episodes of acute sinusitis, however, you may be prone to develop chronic rhinosinusitis. Other causes of chronic rhinosinusitis may be an immune deficiency disorder (for example, primary immune deficiency disease or HIV infection) or an abnormality in the quality of mucus produced by the respiratory system (cystic fibrosis).
Another group of people who may develop chronic sinusitis are those with significant anatomic (structure) variations inside the nose, such as a deviated septum, that lead to blockage of mucus.
Because your nose can get stuffy when you have a condition like the common cold, you may confuse simple nasal congestion with sinusitis. A cold, however, usually lasts about 7 to 14 days and goes away without treatment. Acute sinusitis often lasts longer and typically causes more symptoms than a cold.
Your doctor can usually diagnose acute sinusitis by noting your symptoms and doing a physical examination, which includes examining your nasal tissues. If your symptoms are vague or persist, your doctor may order a computed tomography (CT) scan, a form of X-ray, to confirm that you have sinusitis.
Laboratory tests your doctor may use to diagnose chronic sinusitis include:
- Blood tests to rule out conditions associated with sinusitis, like an immune deficiency disorder
- A sweat test or a blood test to rule out cystic fibrosis
- Tests on the material that is inside your sinuses to detect bacterial or fungal infection
- Biopsy of the membranes (linings) of the nose or sinuses to determine the health of the cells lining these cavities
After diagnosing sinusitis and identifying a possible cause, your doctor can suggest various treatments.
If you have acute sinusitis, your doctor may recommend:
- Antibiotics to control a bacterial infection, if present
- Pain relievers to reduce any pain
- Decongestants to reduce congestion
Even if you have acute sinusitis, your doctor may choose not to use an antibiotic because many cases of acute sinusitis will end on their own. But if you do not feel better after a few days you should contact your doctor again.
You should use over-the-counter or prescription decongestant nose drops and sprays only for few days. If you use these medicines for longer periods, they can lead to even more congestion and swelling of your nasal passages.
If you have an allergic disease along with sinusitis, you may also need medicine to control allergies. This may include a nasal steroid spray that reduces the swelling around the sinus passages and allows the sinuses to drain. If you already have asthma and then get sinusitis, your asthma may worsen. You should stay in close touch with your doctor to modify your asthma treatment if needed.
Doctor often find it difficult to treat chronic sinusitis successfully. The two main forms of treatment that are used, nasal steroid sprays and long courses of oral antibiotics, alone or in combination, have not been rigorously tested in chronic sinusitis. Scientists need to do more research to determine what the best treatment is.
Many doctors also recommend using saline (saltwater) washes or sprays in the nose to help remove thick secretions and allow the sinuses to drain.
If you have severe chronic sinusitis, your doctor may prescribe oral steroids, such as prednisone. Because oral steroids are powerful medicines and can have significant side effects, you should take them only when other medicines have not worked.
When medicine fails, surgery may be the only alternative for treating chronic sinusitis. The goal of surgery is to improve sinus drainage and reduce blockage of the nasal passages. During surgery, usually done through the nose, the surgeon:
- Enlarges the natural opening of the sinuses
- Removes any polyps
- Corrects significant anatomic deformities that contribute to the obstruction