Epidemiology

The population prevalence is reported as 2-4%, with no racial predilection.^[2]

Aetiology^[3][4]

The exact pathogenesis is not known. Nasal polyps have been linked with chronic inflammation such as in chronic rhinosinusitis and vasculitis. Superantigens produced by Staphylococcus aureus may play a role.^[2][5] Polyps usually start close to the ostiomeatal complex (the sinus ostia) of the nasopharynx.

Histological examination reveals that in most polyps there are sac-like entities with an eosinophil-rich oedematous wall; their poor blood supply gives them a pale appearance. Over time, they may become fleshy and reddened due to squamous metaplasia. Benign and malignant nasal tumours can mimic or co-exist with nasal polyps.

Nasal polyps can be classified as eosinophil-rich (the most common type in the UK), infective, or due to other causes.

Associations^[3]

• Asthma.
• Aspirin sensitivity.
• Cystic fibrosis (particularly nasal polyps in children).
• Allergic fungal sinusitis (rare in the UK but more common in warmer areas).
• Churg-Strauss syndrome.

Nasal polyps are not associated with allergy.

Presentation

Symptoms

Patients may have a history of recurring acute or chronic sinusitis. Symptoms depend on the size of the polyp (small polyps may be asymptomatic) and include:

• Nasal airway obstruction.
• Nasal discharge:
  • Watery anterior rhinorrhoea, sneezing, postnasal drainage.
  • Green secretions suggest infection (due to a polyp blocking the sinus ostia).
  • Unilateral, blood-tinged secretion suggests a tumour, foreign body, nose picking, or misapplication of nasal spray.
• Dull headaches.
• Snoring and obstructive sleep symptoms.^[6]
• Hyposmia or anosmia (decreased smell), and reduced taste.

Examination^[3][4]

A nasal speculum will allow visualisation up until the anterior edge of the middle turbinate (in good conditions). Misting of the speculum helps confirm good airflow. The nose may be examined with an aural speculum if nasal equipment is lacking.

• Nasal polyps can be distinguished from the inferior turbinate by their lack of sensitivity, their yellowish-grey colour and by your ability to get between them and the side wall of the nose.^[3]
• The nasal bridge may be widened in patients with nasal polyps; it may be depressed in patients with Wegener's granulomatosis.
• Using an aural speculum, look for single, or clusters of, grape-like structures. Very large polyps may grow down into the oropharynx and can be visualised with a tongue depressor. Smaller polyps may not be visible without nasendoscopy.
• Decongestants and local anaesthesia may help examination.

Differential diagnosis

• Nasal polyps tend to be bilateral. With unilateral lesions, suspect a tumour (and in children, rule out an encephalocele).^[4]
• Foreign body - particularly if there is unilateral, blood-tinged discharge in young children.^[3]
• Chronic rhinosinusitis without polyps.
• Sinusitis.
• Allergic fungal rhinosinusitis.
• Tumours, benign and malignant - eg nasopharyngeal carcinoma, dermoid tumour, encephalocele and others.^[7]

Be aware of associated conditions (above), including cystic fibrosis in children with nasal polyps.

Investigations^[3]

Ear, nose and throat (ENT) investigations:

• Rigid or flexible endoscopy (rhinoscopy) carried out by specialists - this allows localisation and determination of the extent of the polyps.
• Plain X-ray films are of limited value - they are not recommended in this scenario.
• CT scans are helpful - they should be reserved for patients failing medical therapy or those with atypical or severe disease.

Investigation for an underlying cause:

• Investigation of underlying chronic rhinosinusitis may be appropriate. This is detailed in guidelines.^[3]
• Patients with severe or recurrent polypoid rhinosinusitis merit investigations for aspirin sensitivity, allergic fungal rhinosinusitis or Churg-Strauss syndrome.

Management^[3]

General principles

• Review for associated/underlying disease (see 'Investigations' section, above), eg covert asthma and aspirin sensitivity.
• As there is no single causative factor, treatment targets the underlying inflammatory process.
• Medical management is first-line, unless the nature of the polyp is uncertain (eg suspected malignancy).
• Patients should be educated regarding the recurring nature of this problem.

Drugs

Topical corticosteroids:

• These are the the mainstay of medical management: in most patients, they improve symptoms and reduce recurrence after surgery.
• Nasal drops are preferred to sprays for nasal polyps. They should be used in the 'head upside down' position (see diagram).
• Systemic absorption is negligible with mometasone and fluticasone, high for betamethasone and dexamethasone, and modest for the remainder.
• Fluticasone, mometasone and budesonide do not seem to affect children's growth - unlike beclometasone. However, take into account other steroid use (eg chest and skin). Growth monitoring is advised for children.
• Patients with glaucoma should be monitored more closely.
• A medical polypectomy refers to the steroid regimen used to treat large polyps (see under 'Medical polypectomy', below).

.

Other possible drugs are:

• Antihistamine (if allergic rhinitis is present).
• Nasal douche (saline).
• Leukotriene receptor antagonists.^[8]
• Antibiotic - long-term macrolide. (Other authors have suggested doxycycline.^[5])
• Azelastine.
• Systemic corticosteroids^[9] - but long-term use is not advised due to side-effects.^[1]
• In one case report, omalizumab (a monoclonal anti-IgE antibody) produced dramatic improvement in nasal polyp symptoms.^[10]

A suggested treatment algorithm is:

• Saline douching and betamethasone drops for 2 weeks.
• If improved, continue saline douching with non-absorbed topical corticosteroid as maintenance.
• If not improved after step 1, try medical polypectomy (below).
• If not improved, try saline douching/topical corticosteroids plus leukotriene receptor antagonists for one month.
• If improved, continue treatment with reducing dose of corticosteroid.
• If not improved after step 5, investigate further - for aspirin sensitivity, vasculitis and allergic fungal sinusitis.
• If tests are negative, add oral macrolide antibiotic - 3-month trial.

Medical polypectomy: this is the regimen used to treat large polyps. It consists of oral prednisolone (0.5 mg/kg) for 5-10 days with betamethasone nasal drops two drops per nostril tds in the 'head upside down' position (see diagram) for 5 days, then twice daily until the bottle runs out. It is followed by maintenance therapy: fluticasone (drops, spray) or mometasone (spray) twice daily until the bottle runs out.

Other treatments

• Aspirin desensitisation may help in aspirin-sensitive individuals (below).
• Surgery: this removes the obstruction, but does not control the symptoms of rhinitis, and polyps can recur.
• Steroid injection of polyps has been used, but there are safety concerns.^[11]

Complications^[1][7]

Severe complications are uncommon. Complications include:

• Acute bacterial sinusitis - with potential complications of intracranial infections (eg meningitis); cavernous sinus thrombosis, orbital complications (periorbital and orbital cellulitis, orbital abscess); and subperiosteal abscess.^[1]
• Sleep disruption.
• May contribute to symptoms of asthma.
• Rarely, massive polyps (such as those occurring in cystic fibrosis or with allergic fungal sinusitis) can lead to craniofacial structural abnormalities with resulting proptosis, hypertelorism (increased interorbital distance) and diplopia.^[7]

Prognosis

There is no single curative treatment and recurrence is common, including after surgery.^[1]

Aspirin-sensitive nasal polyposis^[3]

Up to 8% of patients with nasal polyps have aspirin/non-steroidal anti-inflammatory drug (NSAID) sensitivity together with chronic rhinosinusitis and (usually) asthma.

Presentation

• Typically occurring in the third and fourth decades of life; more common in females and in non-atopics.
• Ingestion of aspirin or an NSAID induces a reproducible reaction within 20-120 minutes:
  • In any individual the form of the reaction is consistent.
  • Any combination of symptoms may occur, including systemic upset with facial flushing, perspiration and intense lethargy, rhinorrhoea, nasal congestion, conjunctivitis, respiratory symptoms (cough and bronchospasm) and gastrointestinal symptoms.
  • A severe reaction can include shock and respiratory arrest.

Diagnosis

Aspirin sensitivity should be suspected in patients with severe or recurrent nasal polyps and intrinsic asthma. The diagnosis relies on either a clear history of two aspirin/NSAID-induced reactions or by aspirin challenge (nasal, inhaled or oral).

Management of aspirin sensitivity

• Patients should be warned to avoid all drugs with COX-1 inhibitory activity. Selective COX-2 inhibitors appear to be safe, but it is suggested that the first dose should be administered in hospital under direct observation with monitoring for 2 hours and resuscitation facilities available.
• Paracetamol is usually (not always) tolerated; single doses of ≤500 mg are safe in 94% of patients.
• A diet avoiding preservatives, additives and high salicylate foods may be helpful (for some patients in open studies).
• Aspirin desensitisation can be carried out in a hospital setting.^[12]
• Surgery is less successful (compared with aspirin-tolerant patients).