Sinusitis is a disease characterised by inflammation of the tissue lining the sinuses. It can affect people of all ages, including children.
Paranasal sinuses are hollow spaces in the bones of the face and skull that are covered in a thin layer of mucosa (soft tissue lining that produces mucus). The sinuses are connected by narrow pathways to the nasal passages.
Healthy sinuses produce mucus that moisturise the inside of the sinuses and nasal passages. This helps to humidify and warm the air we breathe, and clear micro-organisms and pollutants from our nasal passages.
When sinusitis occurs, the mucosal lining becomes inflamed and swollen, and produces a much larger amount of inflammatory mucus. This inflammation can lead to:
In general, there are 3 types of sinusitis:
Acute sinusitis, also known as acute rhinosinusitis, can last up to 4 weeks. It can be classified into:
Chronic sinusitis is also known as chronic rhinosinusitis (CRS). The change from acute to chronic sinusitis is a gradual process of persisting sinus inflammation. Symptoms must be present for at least 12 weeks.
CRS can be broadly classified into 2 types, with possible overlapping of features:
Fungal sinusitis may be caused by fungal organisms in 3 ways:
The symptoms of sinusitis include:
In addition, you may experience a reduced sense of smell and taste, tiredness, fever or a sense of general malaise.
In general, you should consult an ENT specialist if you have the following symptoms:
If you experience any of the following symptoms, you should consult an ENT specialist immediately, as they may suggest severe complications of sinusitis (e.g. infection spreading to the eyes or brain):
Sinusitis is usually due to a combination of factors acting at the same time, often triggered by a viral upper respiratory tract infection that predisposes you to secondary bacterial infection and impaired clearance of inflammatory mucus.
These factors include:
Examples of structural abnormalities include a deviated nasal septum that may narrow the outflow tract of the sinuses.
Untreated allergic rhinitis (allergic inflammation of airways in the nose) is one of the factors that can lead to sinusitis.
Dental infections such as tooth infections usually cause isolated maxillary sinusitis.
If you have a weakened immune function, fungal sinusitis, viral infections and bacterial infections may lead to sinusitis.
Risk factors for sinusitis include:
Nasal polyps are painless, soft and non-cancerous growths on the nasal passages or the lining of your sinuses.
People with asthma are prone to developing sinusitis. This is because asthma causes the airways to narrow and swell, which may produce extra mucus and result in breathing difficulties. Asthma may also trigger coughing, wheezing and shortness of breath.
Regular exposure to pollutants such as tobacco smoke can trigger sinusitis.
Health conditions like HIV, cystic fibrosis and other immune system-related diseases can lead to nasal blockage, which increases your risk of sinusitis.
While sinus infection is generally not life-threatening, it can lead to complications if left untreated. These complications include:
Sinus infection can spread to the eyes. In the early stages, the eyelids may become swollen. As the infection progresses, the eye itself becomes swollen and painful. The structures of the eye may be damaged and result in vision problems such as double vision or blindness.
Untreated sinusitis may lead to blood clots in the cavernous sinus (an important venous system at the base of the brain). These blood clots can:
Infection of the sinuses may spread to the meninges (membranes surrounding your brain). Classic symptoms of a meningeal infection include high fever, headache and neck stiffness, and altered neurological function.
Further bacterial spread can lead to the formation of brain abscesses (accumulation of pus and breakdown products from infection). The swelling and pressure of the brain tissue can cause neurological deficits and coma.
The bacterial infection from the sinuses may spread to the surrounding bone, especially the bone of the forehead. This can lead to persistent headache, fever, swelling of the bone and discharge of pus through the skin.
You can prevent sinusitis by: