Chronic rhinitis (chronic rhinitis): causes and pathogenesis
Last reviewed: 23.04.2024
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Causes of chronic rhinitis
As a rule, the emergence of chronic rhinitis is associated with discirculatory and trophic disorders in the mucous membrane of the nasal cavity, which can be caused by such factors as frequent acute inflammatory processes in the nasal cavity (including various infections). Negative influence is also exerted by irritating environmental factors. So, dry, hot, dusty air dries out the mucous membrane of the nasal cavity and depresses the function of the ciliated epithelium. Prolonged exposure to cold leads to changes in the endocrine system (especially in the adrenal glands), which indirectly affect the development of a chronic inflammatory process in the mucosa of the nasal cavity. Irritant toxic effects on the mucous membrane of the nasal cavity are caused by certain industrial gases and toxic volatile substances (for example, mercury, nitric, sulfuric acid vapor), as well as radiative forcing.
An important role in the development of chronic rhinitis can be played by common diseases, such as diseases of the cardiovascular system (eg, hypertension and its treatment with vasodilators), kidney disease, dysmenorrhea, frequent coprostage, alcoholism, endocrine system disorders, organic and functional changes of the nervous systems, etc.
In addition, local processes in the nasal cavity, paranasal sinuses and pharynx are important etiological factors of chronic rhinitis. Narrowing or obturation with hoan adenoids promotes the development of stasis and edema, which in turn leads to an increase in mucus and an increase in bacterial contamination. Purulent discharge with sinusitis infects the nasal cavity. Violation of normal anatomical relationships in the nasal cavity, for example, with the curvature of the septum of the nose, leads to unilateral hypertrophy of the nasal concha. Hereditary prerequisites, malformations and defects of the nose, traumas, both domestic and operational (excessive radical or repeated surgical intervention in the nidus cavity) may be important. Contribute to the development of chronic inflammation of the nasal cavity foreign body of the nasal cavity, chronic tonsillitis and prolonged use of vasoconstrictive drops.
An important role in the development of chronic rhinitis is played by nutritional conditions, such as monotonous food, lack of vitamins (especially group B), lack of iodine substances in water, etc.
Pathogenesis of chronic rhinitis
The combined effect of some exogenous and endogenous factors during a different period of time can cause the appearance of some form of chronic rhinitis. So, mineral and metal dust traumatizes the mucous membrane, and flour, chalk and other types of dust cause the death of cilia of ciliated epithelium, thereby contributing to the appearance of its metaplasia, the violation of outflow from the mucous glands and goblet cells. Dust accumulations in the nasal passages can be cemented and form nasal stones (rhinolites). The vapors and gases of various substances exert a chemical effect on the nasal mucosa, causing at first its acute and then chronic inflammation.
Various forms of chronic rhinitis are characterized by inherent pathomorphological changes in the nasal cavity.
With chronic catarrhal rhinitis, pathomorphological changes are not very pronounced. The most pronounced changes occur in the epithelial and subepithelial layer. The integument epithelium is thinned; in places, metaplasia of the ciliated cylindrical epithelium into the flat epithelium is observed. In some areas, the epithelial cover may be absent. The number of goblet cells increases. In the subepithelial layer there is a marked infiltration of the tissue, mainly by lymphocytes and neutrophils. Mucous subepithelial glands are enlarged due to the secret accumulated in them. Disappears synchronicity in the action of the secretory glands. Especially pronounced infiltration with lymphoid elements is observed around mucous glands. Inflammatory infiltration can be not diffuse, but focal. Sclerosis develops with a prolonged course of rhinitis in the subepithelial layer. The surface of the mucous membrane is covered with exudate, which consists of a secretion of mucous and goblet glands and leukocytes. The number of leukocytes in the exudate varies depending on the severity of the inflammatory phenomena.
Morphological changes in chronic hypertrophic rhinitis largely depend on the form of the disease. On all sites of the mucous membrane a proliferative process is observed. The epithelial cover is diffusely thickened, sometimes hyperplastic, a thickening of the basal membrane is observed. Infiltration of the lymphoid, neutrophil and plasma cell is most pronounced in the glands and vessels. The fibroblastic process begins in the area of the location of the glands and the subepithelial layer, reaching a vascular layer in the future. Fibrous tissue either squeezes the cavernous plexus of the shells, or promotes their expansion and neoplasm with the vessel. The compression of the excretory ducts of the gland leads to the formation of cysts. Sometimes there is bone hyperplasia of the shells. In the polypoid form of hypertrophy, the edema of the mucous membrane is more pronounced, with papillomatoenic hypertrophy, changes are observed in the epithelial layer, the hyperplastic layers of the epithelium are immersed in some areas, and the fibrosis of these areas is markedly expressed. Morphological changes in nonspecific chronic atrophic rhinitis are observed in the mucosa. At the same time, along with atrophy, a completely normal mucosa is revealed. The greatest changes are noted in the epithelial layer: there is no mucus on the surface of the mucous membrane, goblet cells disappear, the cylindrical epithelium loses its cilia, and is metaplazed into a multilayered plane. In later stages, there are inflammatory infiltrates in the subepithelial layer, changes in mucous glands and blood vessels.
With vasomotor rhinitis (neurovegetative form), the decisive role in pathogenesis is played by the disruption of the nervous mechanisms that determine the normal physiology of the nose, as a result of which the usual irritants cause hyperergic reactions of the mucous membrane. With this form of rhinitis, there are no specific changes in the nasal mucosa. The lining epithelium is thickened, the number of goblet cells is greatly increased. Observe the breakdown and puffiness of the underlying layer. The cellular reaction is poorly expressed and is represented by lymphoid, neutrophilic, plasma cells and macrophage foci. Cavernous vessels are dilated. With a long course of the disease, there are signs characteristic of hypertrophic rhinitis (collagenosis of interstitial tissue).
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