A sinus is a hollow, air-filled cavity. Sinus refers to the hollow cavities that are in the skull and connected to the nasal airway by the ostium, a narrow hole in the bone. A person has four pairs of sinuses each referred to as the:
- Frontal sinus, located in the forehead
- Maxillary sinus, located behind the cheeks
- Ethmoid sinuses, located between the eyes
- Sphenoid sinus, located deep behind the ethmoids.
The four pairs of sinuses are described as a unit and termed the paranasal sinuses. The cells of the inner lining of each sinus are mucus-secreting epithelial cells and some cells that are part of the immune system.
The sinuses have various functions, including the humidification and warming of the inspired air, providing insulation to the surrounding structures such as the eyes and the nerves, increasing the resonance of the voice, and as protection against trauma of the face. Also, the sinuses make the weight of the skull lighter. If the inflammation hinders the clearance of mucous or blocks the natural ostium, the inflammation may progress into a bacterial infection.
Sinusitis is the swelling or inflammation of the tissue lining the sinuses. Healthy sinuses are filled with air. When they are blocked or filled with fluid, germs may grow, causing an infection. The inflammation of the tissue lining the sinuses may also be caused by allergies and particulate or chemical irritation of the sinuses.
Most people do not spread sinus infection to other people.
Sinusitis may be classified as:
- Acute sinusitis - It usually begins with cold-like symptoms such as the stuffy or runny nose and facial pain. It may start suddenly and lasts 2 to 4 weeks.
- Subacute sinus inflammation - It usually lasts 4 to 12 weeks.
- Chronic inflammation - It lasts 12 weeks or longer.
- Recurrent sinusitis - It happens many times a year.
Signs and symptoms of inflammation of the tissue lining the sinuses or sinus infection
There are various signs of sinusitis and sinus infections. Most patients have several signs and symptoms at the same time. Some patients may have some intermittent symptoms, while most have symptoms at once. The signs and symptoms of sinusitis or sinus infection include:
- Headache caused by the pressure blocked sinuses, whether partial or complete. The pain will become worse when the person is bending down.
- Swelling or facial tenderness when the areas in the face over the sinus are touched.
- Pain or pressure due to the pressing of the mucus on sinus tissue or inflammation of sinuses.
- Fever caused by the infection and the inflammation of the sinus tissues.
- A cloudy and discolored nasal drainage that is often seen in bacterial infection.
- Congestion or feeling of nasal stuffiness, which occurs with infectious sinusitis.
- Postnasal drip or overproduction of mucus due to sinusitis, which flows to the throat and irritates the throat tissues.
- Sore throat, an inflammation of the throat tissue caused by postnasal drip.
- Cough as a response to postnasal drip and body’s attempt to clear out the irritants on the throat.
- Tooth pain caused by pressure on the nerves and tissues that surround it.
- Ear pain caused by pressure on the surrounding nerves and tissues.
- Eye pain due to pressure on the nerves and tissues that surround it.
- Fatigue caused by fever, an immune response to coughing.
- Bad breath caused by bacterial infections.
- Sneezing/itching - A common allergy symptom but also a symptom of infectious sinusitis.
- Nasal drainage, usually whitish when there is non-infectious sinusitis.
- Ulceration caused by rare fulminant fungal infections with defined edges and necrotic centers in the nasal area.
- Multiple chronic symptoms that are usual signs of chronic or subacute sinusitis.
Sinusitis or sinus infection may be caused by anything that interferes with the airflow into the sinuses and the drainage of mucus out of the sinuses. The opening of the sinus - ostea - could be blocked when there is swelling of the tissue lining and the surrounding nasal passage tissue caused by the common colds, tissue irritants such as nasal sprays, allergies, and cigarette smoke.
Other causes of sinusitis include the following:
- Growth or tumors that can block the sinuses if they appear near the openings.
- Disease, dehydration, medications that cause dryness and the absence of enough humidity can lead to sinusitis or sinus infection. The mucus drainage from the sinuses may also be impaired when the mucus secretion is thick. Damage to the cilia, usually by smoke, may cause irritation, which prevents them from helping in the drainage of the mucus from the sinuses.
- Stagnant mucous becomes an environment that is conducive to bacterial growth, also virus at times.
- Immunodepression or victims of multiple traumas.
Diagnosis and Treatment
Sinusitis or sinus infection is often diagnosed based on your history and an examination of a doctor. Most sinusitis or sinus infection is initially diagnosed and treated by a doctor based on clinical finding on examination, ruling out X-ray studies because they could be misleading when it comes to sinusitis, while procedures such as MRI and CT scans are very expensive and may not be available in some doctor’s offices.
The doctor’s physical findings may include:
- Swelling and redness of the nasal passages
- Purulent drainage from the nasal passages, typically the symptom of a sinus infection
- Tenderness to tapping over the forehead or cheeks region of the sinuses
- Swelling around the eyes and cheeks.
In some cases, nasal secretions are examined for secreted cells to help differentiate between infectious and allergic sinusitis. Infectious sinusitis usually shows specialized cells of infection while allergic sinusitis will show specialized white blood cells of allergy. When bacterial infection is suspected, the doctor typically prescribes antibiotics. Antibiotics are not effective in treating viral infections, which makes doctors treat only the symptoms.
MRI or CT scans may be performed when the sinus infection did not respond to the first treatment given by the doctor. The scans will be used for deeper studies of the infection. Although not as accurate as MRI and CT scans, ultrasound proved to be successful when used in pregnant women to diagnose sinus infections.
Endoscopy or rhinoscopy are procedures used to look directly in the back of nasal passages with the help of a small flexible fiberoptic tube. They are used to directly look at the opening of the sinus and look for blockages either by growths or swelling.
It may be necessary to use a needle aspiration of a sinus to collect sample infected material to be cultured to identify the microbe that causes the infection of the sinus. Cultures of tissues collected from the nasal passages may help in determining the fungus or bacteria that cause a sinus infection because typically, nasal passages are inhabited by non-infecting bacteria. The needle puncture requires local anesthesia to minimize discomfort. The aspirated content is sent to the laboratory for culture and staining. Usually, the sinus is flushed with saline solution. This procedure is the most accurate way of diagnosing infectious sinusitis.
Viral sinusitis - Antibiotics are not typically administered for viral sinusitis. Common treatments include fever and pain medications, such as acetaminophen. Mucolytics and decongestants are used to dissolve or breakdown mucus.
Bacterial sinusitis - Acute bacterial sinusitis is usually treated with antibiotics for the treatment of common bacteria known to a cause sinus infection, such as:
- Streptococcus pneumoniae
- Moraxella catarrhalis
- Haemophilus influenzae
- Staphylococcus aureus
- Streptococcus pyogenes
Amoxicillin is used for uncomplicated acute sinus infections. Many doctors, however, prescribe amoxicillin-clavulanate as the first-line antibiotic for the treatment of bacterial infection of the sinuses. It is usually effective against most of the strains of bacteria.
If you are allergic to penicillin, other antibiotics may be used, such as:
If there is no improvement in your condition after taking the antibiotic after five days, contact your doctor as he may want to change antibiotics to one of the antibiotics listed above or amoxicillin-clavulanate.
Typically, an effective antibiotic must be used continuously for a minimum of 10 to 14 days.
Risks of Having Inflammation of the Tissue Lining the Sinuses
Lots of people have sinusitis at least once every year. It is more likely to occur if you have:
- Swelling inside your nose such as from a common cold
- Structural differences that make the ducts narrow
- Blocked drainage ducts
- Deficiency in the immune system or the use of medications that suppress the immune system.
Among children, the following may cause sinusitis:
- Illnesses from other kids at school or daycare
- Bottle drinking while lying on the back
- Smoke in the environment
When to Seek Medical Attention
You need to schedule an appointment with your doctor if:
- You have had sinusitis many times, and the condition does not respond to treatment
- Your symptoms do not improve after seeing your doctor
- Your sinusitis symptoms last for more than 10 days
Immediately see your doctor if you have the following signs or symptoms, which could be indicative of serious infection:
- Severe headache
- Swelling or redness around the eyes
- Swelling at the forehead
- Double vision or other vision changes
- Stiff neck