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Hopkins C, Surda P, Walker A, Wolf A, Speth M, Jacques T, et al. EPOS 4 patients. Rhinology. 2021 Suppl. 30: 1-57.

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Chronic rhinosinusitis
with nasal polyps

What are the sinuses?

The nasal cavity starts at the nostrils and travels backwards towards the throat. It is separated into left and right sides by a wall in the midline called the nasal septum. The sinuses are air-filled spaces within the bones of the face that connect into the nasal cavity on both sides.

There are four groups of sinuses on each side: maxillary, frontal, sphenoid and ethmoid. The maxillary sinuses are large single cavities that occupy most of the space behind the bone of the cheeks. The frontal sinuses are behind the eyebrows and forehead. The sphenoid sinuses are at the very back of the nasal cavity, in the central part of the skull. The ethmoid sinuses are slightly different to the other sinuses – they occupy the space between the eyes, and have many smaller cells separated by very thin bone, like a honeycomb. We don’t fully understand what role the sinuses evolved to do, and some people have missing or underdeveloped sinuses without developing any problems.




















What do the sinuses do?

The sinuses are lined by the same tissue that lines the nasal cavity. In the normal situation, they continuously secrete a small amount of mucus, which travels naturally out of the sinuses and into the nasal cavity, where it eventually passes backwards into the throat. This mucus helps to keep the air that you breathe in moist, and also helps to trap and deal with any viruses and bacteria.

In some conditions, patients develop long-term inflammation in the sinuses and nasal cavity. The most common of these conditions is chronic rhinosinusitis, where the lining of the entire nasal cavity and the sinuses becomes inflamed. Chronic rhinosinusitis is a disease with several different forms, caused by different kinds of inflammation.

Chronic rhinosinusitis with nasal polyps (CRSwNP)

Chronic rhinosinusitis (CRS) can be divided into categories. Some kinds of CRS cause the patient to develop nasal polyps,

and some kinds do not. Nasal polyps are benign inflamed swellings that fill the sinuses and nasal cavity and sometimes require surgical removal.

As the name suggests, chronic rhinosinusitis with nasal polyps (or polyposis) refers to the condition where the sinuses and nasal cavity are continuously inflamed and produce nasal polyps. The word “chronic” means that the condition affects patients in the long term (for at least 12 weeks, and often for years or decades). This distinguishes it from “acute rhinosinusitis”, which is a short-term illness that often results from a viral infection or common cold, but usually gets better within 2-3 weeks.

CRSwNP is a long-term condition, caused by abnormal inflammation of the lining of the nose and the sinuses. It currently does not have a “cure”, but it can usually be controlled with a combination of medical and surgical treatment.


How is CRSwNP diagnosed?

Patients with chronic rhinosinusitis with nasal polyps (CRSwNP) experience nasal symptoms over the long term:

In order to be diagnosed with CRSwNP, you have to be experiencing at least two of these symptoms over more than 12 weeks, and your symptoms must include blockage or discharge. In addition to the symptoms it causes, CRSwNP is also diagnosed by an ENT doctor examining inside the nose. Examining the nose with an endoscope (a thin fibre-optic camera) allows the ENT doctor to determine whether you have the form of the disease with or without nasal polyps. It also allows them to see evidence of an inflamed nasal lining, or abnormal coloured mucus draining from the sinuses.

The diagnosis of CRSwNP is also supported by performing a scan (usually a CT scan) of the nose and sinuses. It is not essential to have a scan to diagnose the condition, but it can be helpful if there is not enough evidence when the doctor examines you. It is also essential to have a scan if surgery is going to be performed. In a patient without any sinus disease, the sinus spaces will appear black on a CT scan, as they are full of air. In a patient with CRSwNP, the sinuses may appear partially or completely full of polyps or mucus with swollen, inflamed sinus lining. This makes the sinus cavities appear grey rather than black on a CT scan. It is important to remember that having mucus or polyps visible on a CT scan does not mean that you have CRSwNP on its own: you must also be experiencing some of the symptoms in the table below.



















ENT specialists may use specific medical questionnaires (known as “patient-reported outcome measures”) to assess the severity of CRS symptoms, and the impact of the disease on patients’ quality of life. The most common of these is the 22-question Sinonasal Outcome Test (SNOT-22), and visual analogue scales, where the patient is asked to rate the severity of each symptom on a scale from 1 to 10.

Blood tests are not essential for the diagnosis of CRSwNP

However, some patients may have blood tests for the diagnosis of possible allergy (skin prick tests are another method of doing this), or to investigate possible immune deficiency or autoimmune diseases. Some patients have a swab of nasal secretions taken, in order to determine which kinds of bacteria are present; however, it is not clear how these results should be used to guide treatment.


What causes CRSwNP?

Our understanding of the different forms of chronic rhinosinusitis is improving constantly. However, for most patients, the exact cause, or “trigger” for developing CRSwNP is not clear, and we do not fully understand why some people develop CRSwNP and others do not. It is likely that each patient with CRSwNP will have a combination of several different factors, which come together to produce long-term inflammation inside the sinuses:


It is important to remember that CRSwNP is not simply an “infection that won’t go away” – the truth is that the relationship between bacteria and CRS is much more complex. Many bacteria and fungi live in our sinuses, both in patients with and without sinus problems. Some bacteria (for example Staphylococcus aureus) may have a role in producing the inflammation in CRSwNP (due to special properties that these bacteria have). However, it is not the case that eradicating the bacteria in the sinuses with antibiotics usually cure the problem.


Medical treatments for CRSwNP

Once a patient is diagnosed with CRSwNP, they should be started on a long-term medication regime. For most patients, this will consist of:


Saline (salt-water) nasal irrigation

Regular saline nasal irrigation is a helpful and effective treatment for most patients with chronic rhinosinusitis. It improves symptoms by improving the flow of mucus, and potentially by washing away irritants and allergens in the nose. However, on its own, it does not decrease the inflammation that causes CRSwNP.


Nasal steroid medication

Nasal steroid medication is the main treatment used for most patients with CRS. Steroids are medications that suppress inflammation, thereby reducing the patient’s symptoms of blockage and discharge. In patients with more severe symptoms from their nasal polyps, steroid drops or steroid rinses are often used in place of sprays.


Other medications

In patients with severe symptoms, short courses (one to two weeks) of oral steroids (usually prednisolone) can be used to give a more rapid improvement in symptoms. This can help at the start of a course of nasal steroid spray or drops, to unblock the nose and give better access to the medications. Short courses of oral steroids can be given 1-2 times per year to enhance the control of CRSwNP. Oral steroids can be taken quite safely in the short term, but they are not generally continued in the longer term because of their side effects.

New biologic treatments (monoclonal antibodies) have recently been approved in some countries for treating patients with very severe nasal polyposis, these medications block the inflammatory pathway and can reduce nasal polyp formation in some patients.


There are separate sections providing more information on all of these treatments.


Surgical treatments for CRSwNP

Chronic rhinosinusitis is treated primarily with medical treatment (see above). The majority of patients will require long-term treatment with nasal steroid sprays/drops, saline irrigation and sometimes other medication. For some patients, this medication alone will be enough to control their symptoms. Where a patient is already taking the maximum amount of medical treatment, but their symptoms are still affecting their quality of life, endoscopic sinus surgery (ESS) can be considered in order to give them better control of their disease.


It is important to be aware that because CRSwNP is a chronic (long-term) condition, treatment does not cure the underlying disease and polyps frequently return. Long-term medication is usually required in order to achieve disease control and patients may require surgery to be repeated.


A patient’s experience of living with CRSwNP

I think the worst thing about it overall is if you don’t keep on top of it can really get you down. In my job as a teacher I have to talk to students, and I sound like have a permanent cold and my words can be unclear it is uncomfortable and can be embarrassing. Fine food and wine used to be one of my greatest pleasures but now eating have just become a necessity as I am unable to smell and taste and no longer enjoy dining out in the same way. There is a safety aspect of not being able to smell as I can’t smell if I am burning something in the kitchen. II can never leave the house without tissues, I’ve always got them, even in the summer I go through boxes of them


What is “type 2” and “non-type 2” inflammation?

Chronic rhinosinusitis (CRS) is a complex disease without a single clear cause. Under the umbrella of CRS, there are different types of disease that likely respond differently to treatments and therefore the best treatment options may differ. For a long time, ENT surgeons have separated patients into two groups based on whether they have nasal polyps or not. Previous editions of EPOS used the same classification to help guide treatment choices, with different pathways for CRS with and CRS without nasal polyps.


However, over the past decade, our understanding of the processes that lead to CRS has significantly improved. We know that in all patients, certain parts of the immune system are over-active, leading to excessive inflammation in the sinuses, and the symptoms of CRS. Which exact part (or “pathway”) of the immune system is over-active varies from patient to patient. In general, we can divide the kinds of inflammation that we see into “types” based on the immune cells and inflammatory mediators involved – the most common in CRS is Type 2, but there are also Type 1 and 3, and this will likely change further as our understanding evolves. We call these different endotypes; they can be thought of as a biological footprint and are probably the best predictor of how a disease will progress over time and how best to treat it. For this reason, EPOS 2020 separates patients into two groups –firstly, those with Type 2 inflammation, and then, secondly, all those with ‘Non-Type 2’ inflammation (ie Type 1 or 3).


Approximately 85% of patients with polyps have Type 2 inflammation, and between 10 -50% of patients without polyps. It is not straightforward to tell whether a patient has Type 1 or Type 2 inflammation, and doctors rely on markers in the blood, tissue and other conditions – for example, we know that patients with severe nasal polyps (CRSwNP) and asthma are more likely to have Type 2 inflammation. At present, a number of new medications (called biologics), which specifically target and reduce Type 2 inflammation are being investigated for their effects in CRS.


Frequently asked questions

How common is chronic rhinosinusitis?

The prevalence of all types of chronic rhinosinusitis (symptoms lasting more than 12 weeks) is around 5%-10% in the general population; it is estimated that roughly 4% of adults have nasal polyps. They are more common in people with asthma.


Is CRSwNP caused by allergies?

No, CRSwNP is not usually caused by allergies. On the other hand, it can happen that patients with chronic rhinosinusitis also have allergies and the other way around. So, if you have chronic rhinosinusitis and symptoms that raise the suspicion of allergy-like sneezing or itch, you can discuss an allergy test with your doctor.


Does CRSwNP cause headaches?

CRS can cause headaches but it is often not the most characteristic symptom of this disease and is less commonly associated with CRSwNP. It is important to realize that headaches without symptoms like runny nose, blockage etc. are very unlikely to be caused by CRS. Headaches associated with CRS are often described as a heaviness or fullness and/or dull sensation. They are first noticed at the same time that other symptoms of CRS started and they usually fluctuate in severity along with other symptoms over time. They get better with successful treatment that improves other symptoms but may get worse with acute infections or when flying.


What’s the difference between turbinates and polyps? Turbinates are normal anatomical structures in the nose that can be found in every human being. They consist of bone and the inner lining of the nose and play a role in the humidification and heating of the inhaled air. Turbinates can be extra swollen for example in case of viral upper airway infection or allergies.


Polyps are expressions of diseased mucosa of the nose and are not normal anatomical structures. They are benign growths that arise from the inner lining of the nose that typically will not go away on their own. They result in symptoms like runny nose, nasal blockage, decreased smell and sensations of fullness or heaviness.


I’m always tired – is it caused by my sinus issues?

If you suffer from chronic rhinosinusitis, this can give rise to symptoms of tiredness, particularly if nasal blockage causes sleep disturbance, which is quite common in CRSwNP.


What happens when I visit the ENT specialist? Do I have to have the camera and does endoscopy hurt?

If you visit the ENT specialist with symptoms of your nose like runny noses or blockage of your nose, he or she will most likely have a look inside of your nose with both a speculum as with a camera (endoscopy). With the endoscope, it is possible to look a little bit deeper inside your nose than with the speculum. Nasal polyps arise a bit deeper/higher up in your nose and often they will not be seen if the doctor only takes a superficial look in your nose without the endoscope.

In general, endoscopy does not hurt and polyps have no sensation. In the rare case it would be a bit painful because your nose is too swollen or because of anatomic variations, local anaesthesia can be used in your nose. Local anaesthesia can for example be applied by placing cotton wools with anaesthetic inside of your nose, before the ENT specialist will perform nasal endoscopy.


I don’t want to keep using medication – it seems like we are just suppressing the symptoms instead of finding the cause. How can I cure this?

Unfortunately, at present, we do not have a cure for nasal polyps. Our treatments are aimed at reducing the symptoms caused by nasal polyps; many patients may require long term intranasal corticosteroids to keep their symptoms under control, but these are safe to use and reduce the need for surgery or oral steroids.


How do I stop my polyps from coming back after surgery?

Using a regular maintenance intranasal corticosteroid after surgery will help to prevent nasal polyps from coming back after surgery.


How do I know if I have Non-steroidal Exacerbated Respiratory Disease (also known as Asprin Exacerbated Respiratory Disease or Samter’s Triad)?

The three main features of Non-steroidal Exacerbated Respiratory Disease (N-ERD) are asthma, chronic nasal polyps, and severe reactions to aspirin and other NSAIDs. Most patients with N-ERD also experience respiratory reactions to alcohol and an impaired sense of smell. Patients usually only develop symptoms in their 30’s to 40’s and they develop over a period of several years. The diagnosis of N-ERD is usually based on the medical history - only occasionally is an aspirin challenge is performed if the diagnosis is unclear.


What’s the best treatment to improve my sense of smell?

Your ENT surgeon can best advise you based on examination findings. Oral steroids, followed by nasal steroids can often improve and then maintain the sense of smell. Unfortunately, in some cases, the sense of smell deteriorates after finishing the course and we wouldn’t recommend more than two courses of oral steroids each year. Endoscopic sinus surgery or biologics would normally be considered in these cases and may further improve the sense of smell.

My ENT surgeon is suggesting surgery for my polyps but my allergist wants to put me on a biologic – what should I do?

Biological treatment is usually only recommended in patients with bilateral nasal polyps who have already had sinus surgery but who have recurrent polyps, or those who are not well enough to have an operation. Sinus surgery and good post-operative intranasal treatment can achieve long term disease control without the need for biological therapies. However, if you have already had surgery but your polyps have come back, biologics are a good alternative. There are pros and cons to both approaches that you need to weigh up and there is no right or wrong answer. Ideally, it’s best to have an


ENT surgeon and allergist who work together but this may some- times be difficult. If they are suggesting different options ask them to explain why, and ultimately you will then need to make a choice based on the information provided and your own preferences.


Why am I not being offered a biologic for my nasal polyps?

Currently, biologic therapies are not available for use in all countries. Where they are available, different criteria may be used to select patients. Generally, these criteria help to identify the patients who are most likely to benefit from biologics and those with more severe disease that is less likely to respond to other treatments.





nasal polyps
factors and causes of chronic rhinosinusitis with nasal polyps

Polyps visible at the enatrance to the nose

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