89 Rhinosinusitis—Chronic (with Nasal Polyps)
Rhinosinusitis is defined differently in children and adults according to the most recent EPOS 2012 conference summary. Please see Chapter 87, Rhinosinusitis-Appropriate Terminology for the correct definitions and classification. Chronic rhinosinusitis (CRS) with nasal polyps is common and is caused by an inflammatory response to a trigger in predisposed individuals. In many instances, the trigger is not identified. Saline nasal douching, nasal and oral steroids and antibiotics are all used to control nasal polyps. Surgery is reserved for those with significant symptoms after maximum medical therapy and should be regarded as just one part of a package of ongoing care for such patients.
89.1 Chronic Rhinosinusitis
This is defined as rhinosinusitis symptoms that have been present for longer than 12 weeks. It is sub-divided into CRS with nasal polyps (CRSwNP) and CRS without nasal polyps (CRSsNP). CRS is common, with an overall worldwide prevalence of 11%, and with a geographic variation of 7 to 27%. There is a strong association of rhinitis and rhinosinusitis with asthma across all ages. This association is strongest in CRS and allergic rhinitis. CRS in the absence of nasal allergies is positively associated with late-onset asthma.
89.2 Chronic Rhinosinusitis with Nasal Polyps
In certain predisposed individuals, an inflammatory nasal condition (such as chronic infection, non-allergic rhinitis, a viral URTI or, in some cases, an unknown trigger) can lead to marked swelling of the sinus and nasal mucosa. This seems particularly to affect the mucosa in the region of the middle turbinate and middle meatus. Polyp formation results when this swelling becomes sufficiently pronounced. Anomalies in the synthesis of prostaglandin and related compounds, collectively known as eicosanoids (these function in diverse physiological and pathological systems including triggering or inhibiting inflammation, allergy and other immune responses) may play a role in polyp formation. In Samter’s triad, for example it has been shown there is an overproduction of eicosanoids. There are a wide range of such compounds and so it may be that there are other prostaglandins over-produced in other inflammatory conditions, triggering polyp formation.
Polyps demonstrate marked oedema of connective tissue stroma. The stroma contains a variety of inflammatory mediators such as histamine, prostaglandins and leukotrienes. There is a marked eosinophilic and histiocytic infiltrate and the epithelium displays goblet cell hyperplasia and, in some areas, squamous cell metaplasia. A polyp forms when the oedematous stroma ruptures and herniates through the basement membrane. Nasal polyps are rare in childhood, and if they occur one should suspect cystic fibrosis or immune deficiency.