Nasal polyps arise from ethmoidal cells but may also rarely develop from the maxillary sinus mucosa (antrochoanal polyps).
In the general population the prevalence of nasal polyposis is about 4% and in patients with asthma 7-13%, whereas in aspirin sensitivity nasal polyps are found in as many as 39-96% of patients 1.
The pathogenesis and aetiology of nasal polyps are only partially known. There are several predisposing factors, and the development of polyps is associated with chronic mucosal inflammation. Aspirin sensitivity and asthma may be the underlying causes of massive and rapidly recurring nasal polyps.
Nasal polyps in children are usually antrochoanal polyps. Nasal polyposis is extremely rare in children and is usually associated with cystic fibrosis Cystic Fibrosis (CF).
Symptoms
Polyps typically cause permanent nasal congestion, rhinitis/mucous production, deterioration of the sense of smell and feelings of pressure/pain over the middle third of the face.
Investigations
Medical history: aspirin sensitivity (asthmatics), airborne allergens and allergies
Palpation of the polyp with a cotton applicator (the polyp will move without causing pain)
If a polyp is suspected, the nose should be examined again after mucosal decongestion (see Nasal Stuffiness for examination of a blocked nose).
Antrochoanal polyps are usually visible only in posterior rhinoscopy.
An ultrasound examination or an x-ray of the paranasal sinuses will mainly yield information about the maxillary sinuses.
Reliable information about the ethmoidal cells can only be obtained with a CT scan or MRI.
Differential diagnosis must be borne in mind and biopsies taken with restraint (see below).
Children must always be referred to a specialist physician - no biopsies should be taken (the "polyp" may turn out to be a meningoencephalocoele or other congenital anomaly).
Differential diagnosis
Biopsy is particularly indicated
in unilateral polyposis
if the polyp tissue feels firm to the touch and bleeds easily.
Benign tumours: including adenoma, papilloma, fibroma, haemangioma, neurilemmoma, chondroma and osteoma.
Papilloma is the most common type of benign tumour. Three different histological types of papilloma are encountered; inverted papilloma carries a risk of malignant transformation. Treatment is surgical.
Osteoma is composed of bone-like tissue, and it is usually encountered in the frontal sinuses (picture 3). Often an incidental finding in paranasal sinus x-rays (appears as a roundish, solid, tumour-like lucency). Monitoring is a sufficient option for osteoma, but should it enlarge surgical excision is indicated.
Malignant tumours (rare): including squamous cell carcinoma and malignant melanoma.
If adequate relief is not obtained with glucocorticoids, polyps that cause nasal congestion and prevent breathing through the nose should be surgically removed.
Surgical removal of nasal polyps (polypectomy)
Prior to polyp removal, a therapeutic trial should be carried out with topical nasal glucocorticoid for a period of 3 months.
Solitary polyps may be removed in primary health care.
Cotton wool swabs soaked in local anaesthetic are placed at the base of the polyp for at least 15 minutes. The anaesthetic solution can be prepared by adding adrenaline (1:1 000) to 4% lidocaine with the ratio of 2-3 drops per 5 ml. In case of several polyps, nerve block anaesthesia may be applied to the nasal mucosa with the aid of cotton-tipped swabs or cotton wool swabs. The application of the swabs is described in an article about the treatment of nasal fractures Fracture of the Nose.
An open wire loop is inserted underneath the polyp and placed around it. The wire is then placed as high as possible towards the base of the polyp The polyp is cut off by tightening the wire loop around the polyp base.
The patient must be monitored until the anaesthetic effect has worn off (about one hour). Any bleeding will usually stop spontaneously or after an application of, for example, a resorbable gelatine sponge.
Further investigations and treatment
A referral to an otorhinolaryngologist is warranted if the patient has several polyps or conservative treatment of 3 months duration proves to be ineffective. The specialist will assess the need for sinus surgery.
In Samter's triad (aspirin sensitivity, asthma and polyposis), nasal polyps recur easily despite all treatment. As regards nasal symptoms in these patients, optimal treatment of asthma is of the utmost importance. In special cases, ASA desensitization performed within specialized care may also be considered.
References
Fokkens W, Lund V, Mullol J, European Position Paper on Rhinosinusitis and Nasal Polyps group. European position paper on rhinosinusitis and nasal polyps 2007. Rhinol Suppl 2007;(20):1-136. [PubMed]