The etiology of this disease is still unclear. It is now believed that chronic infection of the upper respiratory tract, metabolic reactions, is the main cause of nasal polyps.
A, chronic infection because of the release of bacterial toxins and inflammatory mediators in the process of infectious inflammation, can make the lymphatic drainage within the mucosa, venous stasis, small blood vessel dilation, increased exudation, mucosal edema, and now the toxins also cause damage to the nerve endings innervating the blood vessels and further expansion of blood vessels, aggravating exudation. The long-term presence of edematous mucosa, the barrier effect is weakened, and can produce repeated infectious inflammatory response, and mucosal edema is further aggravated, and finally contribute to the formation of polyps. Infection may promote the growth of polyps, but is not a necessary condition for the development of polyps.
Second, the main basis of the metaplasia is: 1, nasal polyp tissue contains high levels of histamine; 2, nasal polyp tissue has a large number of eosinophil infiltration and degranulated mast cells 3, nasal meat tissue has IgE-producing cells, polyps in the fluid IgE levels higher than serum 4, nasal polyp tissue stimulated with specific allergens, can cause the release of the same chemical mediators and IgE-mediated metaplasia; 5, and nasal mucosa Compared to the nasal mucosa, arachidonic acid metabolism is significantly higher in nasal polyp tissues, resulting in the production of large amounts of leukotrienes and inflammatory cell chemokines.
The above facts suggest that the local IgE-mediated metaplasia occurs in the nasal mucosa, releasing large amounts of histamine, leukotrienes and inflammatory cell chemokines, and these chemical mediators can cause local vasodilation, increased exudation, tissue edema, glandular hyperplasia, eosinophil infiltration, and eosinophils can release cytotoxic substances such as major alkaline proteins, which can destroy the nerve endings of the small blood vessel wall, more favorable to small vasodilation and Exudation increases. This localized allergic reaction is difficult to detect by conventional allergen skin tests or serological tests, because specific IgE is mainly present in the polyp capsule fluid.
In summary, nasal polyps are the result of multiple factors. The factors that play a major role can vary depending on the condition, but all cause an inflammatory response in the local mucosa. Eosinophil infiltration and degranulated mast cells, and extreme tissue edema constitute the pathological basis of nasal polyps.