Sinusitis

What is sinusitis?

Sinusitis (or the medical term rhinosinusitis) typically occurs when there is inflammation of the mucosal membranes within the sinuses. This obstructs the flow of mucus out of the sinuses and leads to build-up of mucus in the sinuses which can then become infected forming pus. Sometimes the swelling and inflammation is so severe the mucosal lining forms small grape like projections called polyps.

What are sinuses and why do we have them?

Sinuses are naturally occurring air-filled spaces in the skull. Each sinus is covered with a mucosal covering. The sinuses are all connected to the nose and mucus produced in the sinuses naturally drain out through the nose. The exact function of our sinuses remains unclear. However, several theories have been proposed. The sinuses may provide a larger reservoir for the heating and humidification of air as we breathe in through the nose. They have been proposed to lighten the overall weight of our skull and function as a crumple zone to protect us against trauma. They also affect the overall resonance of our skull and voice quality.

What are the types of sinusitis?

Sinusitis, or a sinus infection, is classified into three main types:

1. Acute sinusitis: Lasts less than four weeks

2. Chronic sinusitis: Lasts more than 12 weeks, and can be loosely divided into chronic sinusitis with polyps or without polyps.

3. Recurrent acute sinusitis: Four or more episodes of acute sinusitis in a year, and symptom-free and well between each episode
   

What are the symptoms of sinusitis?

There are four main symptoms of sinusitis:

1. Difficulty breathing through the nose
2. Pain or discomfort in the cheek, forehead area or between the eyes (which can feel like throbbing pain or sensation of fullness or heaviness)
3. Thick yellowish or greenish nasal discharge – this can drain out through the nose or drip back into the throat
4. Altered smell/taste (hyposmia – reduced smell/taste) or cacosmia (foul smell in the nose)

Some people may also experience other general symptoms such as fever, nausea, vomiting or general tiredness.

When should you see a doctor?

• Your sinusitis symptoms last longer than ten days
• If they worsen after initially improving
• If you experience severe pain, high fever or persistent nasal discharge
• If you have recurrent sinus infections
• Difficulty breathing
• Swelling around the eyes or forehead
• If you develop vision changes
• If over-the-counter treatments provide no relief
• You have an underlying condition such as asthma
• You have a weakened immune system and medical condition
  

What causes sinusitis?

• Viruses are the most common cause of sinusitis and these infections usually resolve fairly quickly with just symptomatic treatment.

• Bacterial sinusitis usually has a longer duration of symptoms and may be treated with oral antibiotics.

• Fungal sinusitis is the least common of the three and usually occurs in those with a weakened immune system. Some pre-existing conditions may make an individual more likely to suffer from sinusitis, these include anatomical abnormalities of the nose, uncontrolled allergic rhinitis and those with depressed immunity and some tooth infections.

What are the risk factors for sinusitis?

Various factors can increase the risk of sinusitis. These include the following:

• Dental infections/procedures
• Nasal instrumentation/procedures
• Mechanical blockage of the nasal passages
  
• Swelling of the nasal lining
• Genetic conditions affecting movement of mucus
• Treatment/therapies that may affect movement of mucus such as radiotherapy to the nose and mouth
• Exposure to cigarette smoke
  

How is sinusitis diagnosed?

When symptoms are suggestive of sinusitis, a nasoendoscopic examination may be performed to look for evidence of polyps or thick yellowish mucus within the sinus openings. The nasoendoscope is a small tubular flexible scope that is introduced into the nose to visualise the nasal passages. Patients are usually given an anesthetic spray prior to performing the nasoendoscopy. This may cause a minor bitter taste which can last up to 1-2 hours. The procedure itself is not a painful one, but some patients may experience a little pressure or discomfort.

In cases of persistent sinusitis, a specimen of the discharge may be taken for culture to identify the bacteria and help in the selection of antibiotics.

Your doctor may also request a computed tomographic scan (CT scan) which can visualise the sinuses affected, and also identify any predisposing anatomical abnormalities.

How is sinusitis treated?

First-line treatment of sinusitis includes nasal saline irrigation (which can be purchased over the counter) and nasal steroid sprays (which a general practitioner may prescribe to you). In particular, for patients with chronic sinusitis, it is important to note that nasal steroid sprays may take time to work and persistent usage of nasal steroid sprays and saline irrigation for a period of up to 6 weeks may be required before a response can be seen. Your doctor may also prescribe antibiotics, however not all patients would require this.

Where symptoms do not respond to appropriate or maximal medical therapy, your ENT doctor may discuss with you a surgical procedure called functional endoscopic sinus surgery (FESS).This is a procedure where the sinus openings are widened with the use of of minaturised scopes and specialised instruments that enable the procedure to be done entirely through the nostril, and typically with no external scars.

Many patients experience great symptom relief with surgery and post-surgical nasal steroid washes. Despite this, there are a small number of patients who continue to have symptoms after surgery. Your ENT doctor may then discuss with you the option of a special class of injection medication called biologics. This has been found to help with some forms of chronic rhinosinusitis with nasal polyps.

If you have co-existent asthma, or symptoms suggestive of it, your ENT doctor may also recommend you to see a lung doctor to optimise asthma treatment.

Patients who smoke are also recommended to stop smoking as cigarette smoke has been implicated in chronic rhinosinusitis.

What are some complications of sinusitis?

Although symptoms of sinusitis can be very troubling, severe complications of sinusitis are rare. These include meningitis/cerebral abscess (spread of sinus infections into the brain lining with pus collection in the brain), osteomyelitis (sinusitis spreading into surrounding bone) and orbital abscess (pus collection within the eye).

Sinusitis can also exacerbate pre-existing upper and lower respiratory conditions such as allergic rhinitis and asthma.  

How can you tell the difference between a cold and sinusitis?

A 'cold' from a simple viral infection is usually self-limiting and resolves within a week. Sinusitis symptoms, while they may be similar to a cold in some aspects such as having running nose and nasal congestion, may last for four weeks or more.

Is it possible for sinusitis to clear up without treatment?

Most cases of sinusitis can be treated with nasal sprays, rinses and supportive care. However, if symptoms worsen or do not resolve, further medical treatment and tests may be warranted.

References

1. Sinus infection: Causes, symptoms & treatment: Acaai Public Website. ACAAI Patient. (2022a, November 7). https://acaai.org/allergies/allergic-conditions/sinus-infection/

2. Battisti, A. S. (2023, March 2). Sinusitis. StatPearls [Internet]. https://www.ncbi.nlm.nih.gov/books/NBK470383/

3. U.S. National Library of Medicine. (n.d.). Sinusitis: Medlineplus medical encyclopedia. MedlinePlus. https://medlineplus.gov/ency/article/000647.htm

4. Mitchell, M. B., Workman, A. D., Lu, R., & Bhattacharyya, N. (2024). Contemporary update on the microbiology of Paranasal Sinusitis. Sinusitis, 8(2), 13–19. https://doi.org/10.3390/sinusitis8020003

5. Fokkens WJ, Lund VJ, Hopkins C,  Wang DY, Zwetsloot CP et al. European Position Paper on Rhinosinusitis and Nasal Polyps 2020. Rhinology. 2020 Feb 20;58(Suppl S29):1-464. doi: 10.4193/Rhin20.600. PMID: 32077450.