Nasal polyps (NP) is a type of chronic rhinosinusitis characterized by abnormal swellings or growths in the mucosal lining of the paranasal sinuses.
Nasal polyps are an abnormal growth with a feature of common teardrop-shape, commonly seen around orifice of the sinus cavities. Most mature polyp have a shape of peeled, seedless grape. Unlike polyps associated with the colon or bladder,nasal polyps are not malignant tumors and have low risk of developing into cancer . They simply indicate inflammation, but sometimes, it may be an inherited condition, therefore family history is important. Biopsy of the nasal polyp may be required to determine if the polyp is malignant or benign.
Nasal Polyps may occur as a result of infection of the sinus or nasal cavity and usually appear following a recovery from an infection. They may develop slowly and persist over a period of time. They may also form due to invasion of nasal cavity by foreign body. Individuals allergic to stimulants such as aspirin or non steroidal anti-inflammatory drugs (NSAIDs) usually develop nasal polyps, asthma, and chronic nasal or sinus congestion. The pathogenesis of nasal polyps and associated respiratory tract conditions due to allergy is not known. Blockage of the sinuses drainage in patient with nasal polyps can result into sinus infections.
Most patient with nasal polyps, are not aware of their condition, although common symptoms include, sneezing, nasal congestion or obstruction, postnasal drip, facial pain, excessive mucoidal discharge in the nose, anosmia, hyposmia, eye itching, and sinusitis.
Based on the British system, NPs are classified into :
Eosinophilic polyps is the most common in the United Kingdom.It is characterized by increase in local polyclonal IgE. The skin patch tests may be negative.
Nasal polyps develop as a result of inflammation of the nasal mucosa tissue. The mucosa layer is a moist lining that protects the nasal cavity, sinuses and help to humidify the respiratory air. When the nasal mucosa is infected or allergic reaction, it becomes swollen, redddish or produce watery fluid that can be dripping out of nasal cavity. Continuous irritation of the mucosa may result into a polyp. A polyp is a grape-shaped growth that obstruct nasal passages.
Hereditary factor may play a role in the development of polyps which may be due to varying genetic expression in the nasal mucosa following inflammation.
The incidence of NP varies with age and sex. In the general children population, the overall incidence rate is 0.1% but among those with cases of cystic fibrosis, 6-48% later develop polyp. In adult, the overall incidence rate is 1-4%, with cases of CF rate of 0.2-28%. More cases of NP were reported among adult male than female with an average ratio of 3:1. A study carried out to determine the prevalence of children with NP requiring surgical treatment, reported an even distribution of the condition among male and female children, although with an inconclusive result . Reported prevalence among asthmatic patient is correlate with the general incidence.
Bernstein's theory proposed that inflammatory changes initially occur laterally at the nasal wall or in sinus mucosa due to microbial-host interactions or as a secondary to disturbance in airflow. Most often, polyps originate from junction of the middle meatus, particularly the small narrow clefts in the anterior ethmoid infundibulum region, which generate turbulent airflow, and especially when constricted by mucosal inflammation. The submucosa may be ulcerated or prolapsed, resulting in formation of new epithelium or gland. When this occur, polyp can develop in the mucosa because of the increased inflammatory reaction in the epithelial cells, endothelial cells blood vessels, and fibroblasts. This may affect the sodium ion channels bioelectric strength of the epithelial cell luminal surface in the nasal mucosa. This result into an increase in sodium absorption, which causes water retention and polyp development .
Other theories described the involvements of vasomotor imbalance or epithelial cells rupture in the development of NP. Vasomotor imbalance theory proposed that increase in vascular permeability and impairment in vascular control following detoxification by mast cell secretions (such as histamine and serotonin). The continuous effects of these secretion on the polyp stroma result in a significant edema (particularly in the polyp pedicle), which may be complicated by venous drainage obstruction. This theory focuses on cell fragility in the polyps stroma, due to the poor cell vascularity and inadequate vasoconstrictor innervation.
Another theory called epithelial cell rupture theory suggested that the rupture of the epithelium in the nasal mucosa result from an increase in tissue turgor in disease conditions (such as during allergic reaction and infections). The rupture causes the lamina propria of the mucosa to prolapse, thereby forming polyps. This condition becomes more aggravated due to gravitational changes or obstructed venous drainage causing the polyps formation. The epithelial cell rupture theory is similar to Bernstein's but the mechanism for polyp enlargement is not well understood. Both epithelial cell rupture and Bernstein theories failed to include the role of inflammatory trigger in NP development.
Nasal polyp management is primarily aimed at reducing the polyp and control of the underlying symptoms. Most often, the treatments are usually long term and do not change the mechanisms of the disease condition. Therefore, it is important to counsel the patient on the regimen plan and the relapsing nature of the clinical condition.
Most commonly, obstruction of the nasal cavity usually present with symptoms such as nasal congestion, stuffy feeling, fullness, or blockage in the cavity. Patient may have difficulty sleeping as the inferior turbinate bone may protrude into the air passage when sleeping in supine position. Poor quality of sleep may be caused primarily by nasal obstruction other than other sleeping disorders such as obstructive sleep apnea . Contralateral sleeping position often increases nasal obstruction, therefore, patient sometimes report sleeping on one side of the body. Also, patient may complain of difficulties in breathing if either or both of the nasal cavity is affected.
Other symptoms that is suggestive of underlying nasal obstruction may be seen. In rhinosinusitis, common symptoms such as facial congestion (fullness), pain or pressure. Also, there may be dysosmia (parosmia or phantosmia), rhinorrhea, nasal discharge, cough, itchy conjunctivitis, sneezing and throat irritation or itching. Various factors affect the subsidence of underlying symptoms of nasal etiology over a period of time. This include, body postural state, seasonal change, and environmental stimulants such as allergens.
The pathophysiology of nasal obstruction is not easy to predict depending on the etiology of the disease. Structural defects (e.g deviated nasal septum (DNS) or hypertrophy of the inferior turbinate) gradually becomes more severe with time. Abnormal changes on the mucosa particularly those initiated by seasonal allergies or harmful stimulants, varies depending on the onset of duration and severity of the condition .
Most often, the severity of nasal obstruction following clinical investigations such as acoustic rhinometry, peak nasal inspiratory flow, and rhinomanometry, usually contradict patient evaluation of the disease condition. For example, a minor difference in nasal patency during assessment could produce severe symptoms in the affected patient.
Various clinical investigations are used to diagnose NP. These include:
Primary treatment of nasal polyp involves the use of oral and topical nasal steroid . Many Clinicians suggested the use of topical nasal steroid in treating nasal polyps as either primary drug of choice or continuous secondary line of treatment after oral steroids or surgical operations. Nasal steroids such as fluticasone, beclomethasone and budesonide was observed to be very effective in managing NP symptoms and increasing the rate airflow in the nasal cavity in a randomized, double-blind, placebo-controlled study. A similar result was observed in systematic reviews of 19 different studies. Topical form of these steroids demonstrated improved therapeutic response in nasal polyposis patients. Previous studies indicated that fluticasone has rapid onset of action and better efficacy compared to beclomethasone .
Failure of the convention treatment in children with benign type of nasal polyposis and chronic rhinosinusitis may require surgical procedure such as simple polypectomy. This is effective in managing non-complex, single and few numbers of polyps. In benign type of multiple 4 nasal polyps, polypectomy iare less effective with report of high recurrence among the patients.
A better surgical technique called endoscopic sinus surgery (ESS) is effective in managing NPs by successfully removing the polyps and expanding the olfactory clefts of the middle meatus, where commonly most polyps develop, thereby preventing the recurrence rate. The degree of the surgical corrections varies depending on the severity of the condition. The correction may range from simple adjustment of the sinus aeration to complete extirpation. Few comparisons revealed that complete surgical extirpation procedures are more effective than sinus aeration with rare complications when handled by an experienced surgeon. Also, with the aid of surgical microdebrider, the procedure is performed faster with minimal risk of error.
Also, antihistamines (e.g cromolyn sodium) and nasal decongestants can be used although, they are less effective. Allergic rhinitis can be treated by immunotherapy methods with better efficacy in resolving latent polyps. Antibiotics may be administered for secondary bacterial infections.
Nasal polyp can be prevented through the following ways;
Nasal polyps (NP) are harmless abnormal growths that develop in the layer of the nasal cavity or sinuses. Polyp is formed when the mucous lining of the nose tender, painfully swollen persisting for long period of time. Sinuses are tiny, air-filled hollow cavities situated in the facial bones. This polyps may obstruct airflow in the nasal cavity and sinuses during breathing thereby causing sinus infections and other related nasal disorders.
The primary cause of NP is not fully understood. However, it is suggested that the condition results from accumulation of fluid in the mucus membranes of the nasal cavity. This initiates the development of fluid-filled swellings which becomes enlarged into polyps. Various factors that can stimulate NP development include, allergens, genetic disorder, and asthma.
Nasal polyps can not be cured, but may be managed using medications. Most commonly, corticosteroid are used for treating NP either as nasal sprays, pills or liquid. Also, antibiotics may be administered for infection treatment in bacterial sinusitis.
Sometimes, complicated cases may required surgery the type of which depends on the severity of the polyp. The most common of the surgery type is endoscopic sinus surgery (ESS). It is a day surgery (outpatient) which might not require prolonged stay in the hospital. It is a specialized technique that involves the use of guided imagery for nasal examination, removal of the polyps and proper drainage of the sinuses.