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Ozena - Causes and Pathogenesis

 
, medical expert
Last reviewed: 08.06.2019
 
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The reason for the development of ozena has not yet been clarified. There are many theories of its occurrence:

  • alimentary is one of the most common theories; people who live in poor sanitary and hygienic conditions and are poorly nourished are often ill;
  • theory of beriberi - lack of vitamins A and D, according to other data - K and group B;
  • anatomical - based on the peculiarities of the structure of the skull, the cavity of the Us and the nasopharynx;
  • hereditary;
  • infectious - the main role is played by a variety of microflora, sown from the nasal mucus in patients with oena (Corynebacterium, Proteus), but most often it is sown with Klebsiella pneumoniae ozaenae; which assign a leading role in this pathology;
  • non-infectious (neurodystrophic) - in the occurrence of ozena, the violation of the vegetative and endocrine systems or sympathetic innervation is of primary importance, which leads to dystrophic processes in the nasal cavity; trophic disorders subsequently lead to osteomalacia, bone resorption and epithelial metaplasia.

Since the end of the XIX century, infectious theory has become dominant. In 1885, Lovenberg discovered capsular diplococcus in patients with ozen, and in 1893r. Abel isolated this microorganism in pure culture, studied its properties and named it Bacillus mucosas ozaenae. Currently, infectious theory and the role of Klebsiella pneumoniae ozaenae can be considered proven.

Pathogenesis of ozena

The process begins with the entry of Klebsiella pneumoniae ozaenae on the surface of the nasal mucosa, sometimes other parts of the upper respiratory tract. The microorganism has a capsule and is located only on the surface of the mucous membrane, causing its inflammation. The inflammatory process in the first, rather long, period has a catarrhal form and is characterized by a significant amount of liquid mucous secretion up to 4 liters per day. Then mucopurulent discharges appear with a large number of leukocytes and lymphocytes, as well as capsular bacteria themselves.

Subsequently, the secret becomes thick, viscous, sticky, which causes its retention in the nasal cavity and the formation of crusts, since nasal breathing during this period has not yet been disturbed.

At the same time, virulent strains of Klebsiella pneumoniae ozaenae on the mucosal surface synthesize a large number of capsular polysaccharides, which cause disruption of the trophism due to the effect on the vessels (their walls become inflamed, the lumen narrows).

Further, Klebsiella pneumoniae ozaenae causes dysbacteriosis in the nasal cavity, slow deterioration of the bone tissue and mucous membranes, leading to progression of the dystrophic process, accompanied by dryness, difficulty of nasal breathing, expansion of the nasal cavity, a large number of crusts with an unpleasant smell characteristic only for osena (fetid, sweetish, nauseous).

Oeeen is characterized by atrophy of all tissues of the walls of the nasal cavity, thinning of the mucous membrane, blood vessels. When Ozen, metaplasia of the cylindrical epithelium is pronounced, it completely degenerates into a flat, desquamous and forms the basis for the crusts. Keratinized epithelium is impermeable to fluid, in connection with which, even in the presence of a large number of glands, the mucous membrane is not softened by mucus. In the sub-epithelial layer around the glands and blood vessels, pronounced leukocyte infiltration is observed. The number of glands decreases, they are replaced by connective tissue. Cavernous tissue becomes empty, in vessels a process resembling obliterating endarteritis is observed. The bone layer of the turbinates contains a large number of osteoclasts - cells that absorb bone. The bone base of the shells is absorbed and replaced by connective tissue. The destruction of proteins is accompanied by the formation of indole, skatole and hydrogen sulfide, which determines the fetid odor from the nose.

trusted-source[1], [2], [3], [4], [5], [6], [7], [8], [9], [10], [11], [12], [13], [14]

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