Pharyngitis: causes and pathogenesis

Causes of pharyngitis

Acute pharyngitis as an independent disease is observed with the direct action of an infectious agent or a variety of irritants (hot or cold strings, inhalation of cold air or air containing harmful impurities, industrial dust, smoking, alcohol, alimentary irritant, etc.). When acute pharyngitis is one of the manifestations of an acute respiratory viral infection, it develops under the influence of the same causes as the underlying disease. The etiological factor of acute pharyngitis can be viruses, microbial pathogens, fungi. The viral etiology of acute pharyngitis is noted in approximately 70% of cases; the causative agents are rhinoviruses of coronaviruses, respiratory syncytial virus, adenoviruses, enteroviruses, influenza virus, parainfluenza, etc. In the period of autumn epidemics, rhinoviruses are responsible for more than 80% of cases of acute respiratory infections. Viral infection can only be the first phase of the disease - it "paves the way" for a subsequent bacterial infection. The beta-hemolytic streptococcus of group A and other groups, which are associated with 31% and 15% of all cases, play the main role from bacterial pathogens of tonsillopharyngitis. There are microorganisms such as Streptococcus pneumoniae, Haemophilus influenzae, Mycoplasma, Staphylococcus aureus, Moraxella, Klebsiella and other microflora, usually found in the nasopharynx in the non-pathogenic form.

Acute inflammation of the pharynx can also develop due to allergic, traumatic effects, as well as under the influence of various irritating factors: hot drink, acids, alkalis, irradiation, etc.

The development of chronic pharyngitis in most cases is due to local prolonged irritation of the pharyngeal mucosa. Contribute to the emergence of chronic pharyngitis repeated acute inflammation of the pharynx, chronic tonsillitis, long-term inflammatory diseases of the nose and paranasal sinuses, violation of nasal breathing. With constantly shortened nasal breathing, pharyngitis can be caused not only by the transition to breathing through the mouth, but also by the abuse of vasoconstrictor drops that drain from the nasal cavity into the pharynx and have an anemic effect there. Symptoms of chronic pharyngitis can develop in the so-called postnasal syndrome, when the pathological secretion from the nasal cavity or paranasal sinuses is flowing down the posterior wall of the pharynx.

The development of chronic pharyngitis can result in exposure to adverse climatic and environmental factors (dust, hot, dry or smoky air, chemicals), smoking, alcohol abuse and g. And

The cause of the disease can be diseases of the gastrointestinal tract (chronic gastritis, cholecystitis, pancreatitis, intestinal dysbacteriosis). For example, the development of chronic pharyngitis often results in the entry of acids of the contents into the pharynx during sleep with gastroesophageal reflux and hernia of the esophageal aperture of the diaphragm.

The development of chronic pharyngitis can result in endocrine and hormonal disorders (menopause, hypothyroidism), allergies, hypo- or avitaminosis A, dental caries, alcohol consumption, acute irritating and excessively hot or cold food. Diabetes mellitus, cardiac, pulmonary and renal accuracy may also cause chronic pharyngitis. Finally, chronic pharyngitis can occur in a number of chronic infectious diseases, for example, in tuberculosis.

Pathogenesis of pharyngitis

Morphological changes in acute pharyngitis are characterized by edema and infiltration of the cellular elements of the mucous membrane, by the expansion and injection of vessels, desquamation of the epithelium. Inflammatory reaction is usually more pronounced in places of accumulation of lymphoid tissue - in the region of the nasopharynx arch, near the mouths of the auditory tubes, on the posterior and lateral walls of the pharynx.

With the catarrhal form of chronic pharyngitis, persistent diffuse venous hyperemia is revealed, the mucosal pastness is caused by the expansion and stasis of veins of small caliber: in this case, perivascular cell infiltration is observed.

The hypertrophic form of pharyngitis is characterized by a thickening of all layers of the mucosa, an increase in the number of rows of epithelium. The mucous membrane becomes thicker and denser, the blood and lymphatic vessels are expanded, lymphocytes are determined in the perivascular space. Lymphoid formations scattered on the mucous membrane in norm in the form of hardly noticeable granules considerably thicken and expand, often due to the fusion of neighboring granules: hypersecretion is noted, the mucosa is hyperemic. Hypertrophic process can be localized mainly on the back wall of the pharynx (granulosis pharyngitis) or on its lateral parts (lateral hypertrophic pharyngitis).

Atrophic chronic pharyngitis is characterized by a sharp thinning and dryness of the mucous membrane of the pharynx; in pronounced cases it is shiny, "lacquered." The size of mucous glands and their number are reduced; Desquamation of the epithelial cover is observed.

[1], [2], [3], [4], [5], [6], [7], [8]