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Sinusitis (Sinus Infection)

  • What is sinusitis?


    Sinusitis is a disease characterised by inflammation of the tissue lining the sinuses. It can affect people of all ages.

    The paranasal sinuses are hollow spaces in the bones of the face and skull that are covered with a thin layer of mucosa (soft tissue lining that produces mucus). The sinuses are all connected by narrow pathways to the nasal passages.

    Healthy sinuses produce mucus that moisturises the inside of the sinuses and nasal passages. This helps the nose to humidify and warm the air that we breathe, as well as to help us to clear micro-organisms and pollutants from the nasal passages.

    When sinusitis occurs, the mucosal lining of the sinuses become inflamed and swollen and a much larger amount of inflammatory mucus is produced. This leads to congestion and discomfort in the sinuses (often described as facial pain), together with symptoms in the nose, such as nasal discharge (often discoloured), nasal obstruction and decrease in sense of smell.

    Types of sinusitis:

    • Acute sinusitis – also known as acute rhinosinusitis, lasting up to 4 weeks.
      • Viral rhinosinusitis – known as the common cold; symptoms typically start to improve after 5 – 10 days.
      • Acute bacterial rhinosinusitis – usually occurs when the common cold does not improve and may last for many weeks.
    • Chronic sinusitis – also known as chronic rhinosinusitis (CRS). By definition, symptoms need to have been present for >12 weeks; however, the change from acute to chronic sinusitis is a gradual process of persisting sinus inflammation. CRS can be classified as follows, but overlap of features may occur in patients:
      • CRS without nasal polyposis (CRSwoNP)
      • CRS with nasal polyposis (CRSwNP). Nasal polyps represent severe swelling of the sinus mucosa. CRSwNP is usually due to an underlying immune dysfunction leading to inappropriate (excessive) inflammatory response. Symptoms buildup is chronic; loss of smell is more common and facial pain is less common.
    • Fungal sinusitis – fungal organisms may cause sinus inflammation in 3 ways:
      • 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.
      • Allergic fungal rhinosinusitis (AFRS) – usually affects multiple sinuses on both sides with marked swelling of the sinus mucosa (polyposis) and thick allergic mucus discharge. AFRS usually occurs in a younger population often with a history of nasal allergies.
      • Invasive fungal sinusitis (IFS) – a severe, potentially fatal condition which usually occurs in immunocompromised patients (eg. diabetes mellitus patients on immunosuppressive treatment) where the fungus causes destruction of tissues in and around the nose and sinuses.
  • Sinusitis is usually a result of a combination of factors acting at the same time, often triggered by viral upper respiratory tract infection, predisposing to secondary bacterial infection and impaired clearance of inflammatory mucus. These factors include:

    • Anatomical variants which may narrow the outflow tract of the sinuses
    • Uncontrolled allergic rhinitis
    • Dental infection (usually causing isolated maxillary sinusitis)
    • Deficiencies in immune function

    Risk factors for sinusitis

    • Nasal polyps – these are painless, soft and non-cancerous growths on the nasal passages or the lining of your sinuses.
    • Asthma – causes the airways to narrow and swell, which may produce extra mucus. It makes it difficult to breathe and triggers coughing, wheezing and shortness of breath. Thus, people with asthma are prone to developing sinusitis.
    • Pollutants – Regular exposure to pollutants such as tobacco smoke can trigger sinusitis.
    • Other medical conditions – Health conditions like HIV, cystic fibrosis and other immune system-related diseases can lead to nasal blockage, which increase the risk of sinusitis.

    Preventing sinusitis

    To help prevent sinusitis, you should not smoke and should also avoid secondhand smoke. Keep your hands clean always, especially during cold and flu season. Avoid touching your face and having close contact with people with upper respiratory infections or colds. Be aware of your allergies and stay away from them. You may also consult your doctor regarding flu and pneumococcal vaccines.

  • The symptoms of sinusitis include:

    • Nasal obstruction
      • Difficulty breathing through the nose due to blockage
      • Mouth breathing
      • Snoring
    • Sinus congestion
      • Feeling full in the face
    • Nasal discharge – often thick and yellow/green
    • Postnasal drip
      • Sensation of mucus in the back of throat
      • Cough with phlegm but sometimes even “dry” cough
      • Bad breath
    • Facial pain
      • Feeling heavy in the head
      • Pain around the eyes, nose, cheeks and forehead
    • Reduced sense of smell and taste
    • Tiredness
    • Fever, general malaise

    You should see an ENT specialist if you have the following:

    • Recurrent sinus infections (eg. >4 times per year)
    • Persistent sinusitis (eg. >1 month)
    • Loss of smell
    • Blood stained nasal discharge

    Symptoms that may suggest severe complications of sinusitis (eg. infection spreading to the eyes or brain) should prompt an urgent consultation. These include:

    • Fever above 38°C
    • Blurred or double vision
    • Swelling and redness around the eyes
    • Stiffness in the neck, mental confusion
    • Severe facial pain or headaches
  • If you experience sinusitis symptoms, your doctor may require you to undergo the following tests:

    Nasal endoscopy

    In this procedure, your doctor inserts a thin, flexible endoscope through your nostrils. The endoscope contains optical fibres which transmit light to illuminate the inside of the nose and real-time images of the nasal passages and entrances to the sinuses. This will allow your doctor to identify abnormalities such as swelling, pus or polyps.

    Imaging tests

    Your doctor may order a computerised tomography (CT) scan or a magnetic resonance imaging (MRI) to obtain more information about your sinus condition, eg. to determine which and how many sinuses are involved and to identify features which suggest more severe disease.

    Sinus and nasal culture

    Your doctor may collect tissue samples or cultures from the inside of your nose or sinuses. These samples are processed in the laboratory to identify bacterial and/or fungal infections. Further information on the antibiotic sensitivity and resistance profiles for the particular bacteria/fungi can also 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. It can help identify the allergens that are involved.

    Blood tests

    Blood tests may be helpful as part of the investigation of sinusitis. For example:

    • 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 severe allergy, some types of chronic sinusitis with nasal polyposis (CRSwNP) and asthma
    • Serum immunoglobulins – low levels of immunoglobulin (eg. IgG and IgA) may be suggestive of underlying immune deficiency, and high IgE may be associated with allergy
  • As there are different types of sinusitis, an accurate diagnosis of the type of sinusitis is a prerequisite for getting the optimal treatment options. Taking into account your particular concerns, your ENT specialist will tailor the most suitable treatment plan for you based on the results of various investigations.

    Non-surgical treatment options

    • Nasal saline (sprays and irrigations)
      These help to clear trapped mucopus (a mixture of mucus and pus) from the nasal passages and pathways to the sinuses and have been shown to improve symptoms in all types of sinusitis.
    • Decongestants (sprays, drops or oral formulations)
      These help to relieve congestion and nasal obstruction. Only short-term use eg. for acute sinusitis, is recommended.
    • Intranasal steroids
      Intranasal steroids are effective anti-inflammatory agents which are useful in the treatment of most forms of sinusitis, helping to improve all the symptoms of sinusitis. They usually come in the form of nasal sprays and are considered safe, even for children.
    • Mucolytics
      These are medications which reduce the viscosity of mucus and can help to improve the clearance of blocked sinus passages.
    • Antibiotics
      In acute sinusitis, antibiotics are useful in the following situations
      • Worsening or lack of improvement after 5 – 7 days
      • Severe symptoms eg. headache, fever
      • Recurrent episodes with short symptom-free intervals
      • Sinusitis with complications
      In chronic sinusitis, the usefulness of antibiotics depends on the clinical situation. In general, antibiotics may be helpful in acute exacerbations of chronic sinusitis. Where possible, the choice of antibiotics should be guided by the results of laboratory samples of the mucopus obtained from the sinuses.

      Some forms of chronic sinusitis may benefit from low-dose macrolide antibiotics prescribed for up to 3 months but it is believed that the effect is due to the anti-inflammatory effect of the macrolide.
    • Allergy treatment
      Inhaled and food allergies may increase the risk of sinusitis. The treatment of allergies may thus be an important component for the holistic treatment of sinusitis.
      • Allergen avoidance
      • Medications, eg. intranasal steroids and antihistamines
      • Specific immunotherapy

    Surgical treatment options

    The surgical treatment of sinusitis is usually by Functional Endoscopic Sinus Surgery (FESS). FESS is a minimally-invasive surgical technique where the sinus surgeon operates on the sinuses through the nostrils without the need for any external incisions. The surgeon visualises the sinus anatomy in real-time, magnified with various endoscopes and uses endoscopic instruments to make precise surgical manoeuvres.

    The aim of FESS needs to be tailored for the type of sinusitis being treated. The most basic goal is to widen the opening of the sinuses for the removal of pus. However, in some cases (eg. nasal polyposis), the purpose of FESS is not simply the removal of polyps but to allow the widest possible access for ongoing treatment including sinus irrigation and patient-administered topical treatments.

    FESS may be an option after a trial of non-surgical treatment modalities for some times of sinusitis. However, some forms of sinusitis require FESS either alone (eg. fungal ball sinusitis) or in combination with other treatments (eg. allergic fungal sinusitis, nasal polyposis).

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  • While sinus infection is generally not life-threatening, complications of sinusitis can happen especially when the infection is left untreated. The complications of sinusitis include:

    Eye infection and abscess

    Infections of the sinusitis can spread to the eyes. In the early stages, the eyelids may become swollen. As the infection in the eye becomes worse, the eye itself becomes swollen and painful. Damage to the structures of the eye can 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). The blood clot can restrict the flow of blood from the brain and can allow the bacteria to be spread through the bloodstream. Injury to the tissues of the brain and eyes can result.

    Brain infection – meningitis and brain abscess

    Infection of the sinuses may spread to the meninges – the membranes surrounding your brain. The classic symptoms include high fever, headache and neck stiffness and altered neurological function.

    Further spread of bacteria can lead to the formation of brain abscesses – an 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.

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