Introduction

Sinusitis is a disease characterised by inflammation, or swelling, 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 pressure and pain in your face, nasal congestion (a stuffy nose) and other symptoms.

Types of Sinusitis

In general, there are 3 types of sinusitis:

• Acute sinusitis : Acute sinusitis, also known as acute

rhinosinusitis, can last up to 4 weeks. It can be classified into:

1. Viral rhinosinusitis : A condition also known as the common cold, where symptoms typically start to improve after 5 – 10 days.
2. Acute bacterial rhinosinusitis : A condition that   usually occurs when the common cold does not improve and lasts for many weeks.
3. Chronic sinusitis : 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:
4. CRS without nasal polyposis
5. CRS with nasal polyposis : Nasal polyps represent severe swelling of the sinus mucosa. It is usually caused by an underlying immune dysfunction that leads to an excessive inflammatory response. The chronic buildup of symptoms typically causes a loss of smell, and sometimes facial pain.
6. Fungal sinusitis : Fungal sinusitis may be caused by fungal organisms in 3 ways:
7. Fungal “ball” or fungal mycetoma : The most common type of fungal sinusitis which usually affects just one sinus. The fungus grows within the sinus, causing localised inflammation.
8. Allergic fungal rhinosinusitis : A condition that usually affects multiple sinuses on both sides, with marked swelling of the sinus mucosa (polyposis) and thick allergic mucus discharge. It usually occurs in younger people with a history of nasal allergies.
9. Invasive fungal sinusitis : A severe & potentially fatal condition that usually occurs in immunocompromised patients, such as diabetes mellitus patients on immunosuppressive treatment. The fungus causes destruction of tissues in and around the nose and sinuses.

Causes

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:

• Anatomical abnormalities of the nose : Examples of structural abnormalities include a deviated nasal septum (DNS) that may narrow the outflow tract of the sinuses.
• Uncontrolled allergic rhinitis : Untreated allergic rhinitis (allergic inflammation of airways in the nose) is one of the factors that can lead to sinusitis.
• Dental infections : Dental infections such as tooth infections usually cause isolated maxillary sinusitis.
• Deficiences in immune function : If you have a weakened immune function, fungal sinusitis, viral infections and bacterial infections may lead to sinusitis.

Symptoms

The symptoms of sinusitis include:

1. Nasal obstruction
   • Difficulty breathing through the nose due to blockage
   • Mouth breathing
   • Snoring
2. Sinus congestion
   • Feeling full in the face
3. Nasal discharge
   • Thick and yellow or green discharge
4. Postnasal drip
   • The sensation of mucus in the back of the throat
   • Cough with phlegm but sometimes even “dry” cough
   • Bad breath
5. Facial pain
   • Feeling heavy in the head
   • Pain around the eyes, nose, cheeks and forehead
   • In addition, you may experience a reduced sense of smell and taste, tiredness, fever or a sense of general malaise.

Risk factors

Some people are more likely to get sinusitis than others. Risk factors include:

1. Nasal polyps : Nasal polyps are painless, soft and non-cancerous growths on the nasal passages or the lining of your sinuses.
2. Asthma : 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.
3. Pollutants : Regular exposure to pollutants such as tobacco smoke can trigger sinusitis.
4. Deviated nasal septum : Your septum is a line of tissue that divides your nose. A deviated septum isn’t straight, narrowing the passage on one side of your nose. This can cause a blockage.
5. Other medical conditions : Health conditions like HIV, cystic fibrosis and other immune system-related diseases can lead to nasal blockage, which increases your risk of sinusitis.

Complications

While sinus infection is generally not life-threatening, it can lead to complications if left untreated. These complications include:

• Eye infection and abscess : 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.
• Blood clot in the cavernous sinus : 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 restrict blood flow from the brain and allow bacteria to spread through the bloodstream, leading to brain tissue injury and eye tissue injury.
• Brain infection – meningitis and brain abscess : 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.
• Bone infection – osteomyelitis : 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.

Prevention

• Not smoking and avoiding secondhand smoke.
• Keeping your hands clean, especially during cold and flu season.
• Avoiding close contact with people with upper respiratory infections or colds.
• Being aware of your allergies and avoiding triggers.
• Getting flu and pneumococcal vaccinations.

Diagnosis

If you have sinusitis symptoms, your doctor may use the following tests to diagnose your condition:

Nasal endoscopy : During a nasal endoscopy, your doctor will insert a thin, flexible endoscope through your nostrils. The endoscope contains optical fibres that transmit light to illuminate the inside of your nose and provide real-time images of your nasal passages and sinus entrances. This allows your doctor to identify abnormalities such as swelling, pus or polyps.

Imaging tests : Your doctor may order Computerised tomography (CT) scan and Magnetic resonance imaging (MRI) scan to obtain more information about your sinus condition. This will help determine which and how many sinuses are affected and identify features that suggest more severe disease.

Sinus and nasal culture : Your doctor may also collect tissue samples or cultures from the inside of your nose or sinuses, and send them to the laboratory to identify bacterial or fungal infections. Further information on the bacteria or fungi’s antibiotic sensitivity and resistance profile can help guide antibiotic treatment.

Skin allergy test : Your doctor may recommend an allergy skin test if they suspect that allergies might be one of the factors contributing to sinusitis. This test helps to identify the allergens that are involved.

Blood tests : Blood tests may be helpful as a part of the investigation of sinusitis. These tests may check your:

White cell count : A high white cell count in the presence of fever may indicate severe acute sinusitis.

Eosinophil count : A high eosinophilic count may be associated with a severe allergy, some types of chronic sinusitis with nasal polyposis, and asthma.

Serum immunoglobulins : Low levels of immunoglobulin (e.g. IgG and IgA) may suggest underlying immune deficiency, while high IgE may be associated with allergy.

Treatment

As there are different types of sinusitis, it is important to get an accurate diagnosis before commencing treatment. Your doctor will recommend the most suitable treatment plan for you based on the results of various investigations.

• Non-surgical treatments : Your doctor may prescribe non-surgical treatment such as:
• Nasal saline (sprays and irrigations) : These improve symptoms by clearing trapped mucopus (a mixture of mucus and pus) from the nasal passages and pathways to the sinuses.
• Decongestants (sprays, drops or oral formulations) : These relieve congestion and nasal obstruction, but are recommended only for short-term use (e.g. for acute sinusitis).
• Intranasal steroids : These effective anti-inflammatory agents usually come in the form of nasal sprays, and help to improve sinusitis symptoms. They are considered safe, even for children.
• Mucolytics : These medications reduce the viscosity of mucus and help to clear blocked sinus passages.
• Antibiotics :
• In acute sinusitis, antibiotics may be useful if you have:
• Worsening or no improvements after 5 – 7 day.
• Severe symptoms, such as headache or fever.
• Recurrent episodes with short symptom-free intervals.
• Sinusitis with complications.
• In chronic sinusitis, the usefulness of antibiotics depends on the clinical situation. Generally, antibiotics may be helpful in acute exacerbations of chronic sinusitis. Where possible, the choice of antibiotics should be guided by the laboratory results of your mucopus samples.
• Allergy treatment : As inhaled and food allergies may increase the risk of sinusitis, your doctor may take a holistic approach to treatment by recommending:
• Allergen avoidance
• Medications, such as intranasal steroids and antihistamines
• Specific immunotherapy

Surgical treatments :

Treatment of chronic sinusitis requires surgery to reverse the obstruction in the sinuses. Surgical options include:

1. Functional endoscopic sinus surgery (FESS)- minimally invasive procedure.
2. Balloon sinuplasty -Less invasive than FESS.

Depending on the type of sinusitis you have, your doctor may either perform FESS alone (e.g. to treat fungal ball sinusitis) or in combination with other treatments (e.g. to treat allergic fungal sinusitis or nasal polyposis).