Sinusitis (Sinus Infection) - Diagnosis & Treatment

How is sinusitis diagnosed?

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 the following imaging tests 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 (CRSwNP), 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.

How is sinusitis treated?

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 days
      • 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.
    • 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 – 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:

  • Functional endoscopic sinus surgery (FESS) – A minimally invasive procedure that inserts an endoscope through the nose to clear out infected tissues. The most basic goal of FESS is to widen the opening of the sinuses for the removal of pus. However, in some cases (eg. nasal polyposis), FESS may be used to remove polyps and allow the widest possible access for ongoing treatment. Examples of ongoing treatments include sinus irrigation and patient-administered topical treatments.
  • Balloon sinuplasty – Less invasive than FESS, this procedure uses specialised instruments to insert a balloon and dilate the sinus opening. The treatment aims to restore normal mucus flow in the sinuses without tissue or bone removal.

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).

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