What causes sinusitis?

Clinical anatomy and physiology of the paranasal sinuses

There are four pairs of paranasal sinuses: frontal, maxillary, lattice and wedge. The frontal sinus resembles a pyramid, its base is the bottom of the sinus. The maxillary sinus medially borders with the lateral wall of the nose, from above with the bottom wall of the orbit, in front with the canine fossa, from below with the alveolar process of the maxilla. Cells of the latticed labyrinth from above are limited by the base of the skull, laterally by a very thin bone plate serving as the medial wall of the orbit. The wedge (main) sinus borders on vital structures: the pituitary gland, the carotid artery, the ophthalmic nerve and the cavernous sinus.

The paranasal sinuses communicate with the nasal cavity through narrow apertures. The frontal and maxillary sinus, as well as the front cells of the latticed labyrinth, open into the anterior part of the middle nasal passage, the sphenoid sinus and the posterior cells of the latticed labyrinth into the upper nasal passage. Natural drainage is provided through these openings; edema, infiltration of their mucous membrane lead to stagnant processes in the sinuses, and consequently, the possibility of sinusitis.

At birth, the child already has the maxillary sinus and several cells of the latticed labyrinth. The maxillary sinus is up to about three years of age above the bottom of the nasal cavity, then gradually descends, and in the adult sinus bottom it can be 0.5-1.0 cm below the bottom of the nasal cavity. It is very important to know about the connection between the teeth and the maxillary sinus. In early childhood, the most closely located to the maxillary sinus is the canine, with approximately 5-6 years of the sinus closely associated with two premolars and molars. The lumbar sinus is finally formed to 7-8 years of age.

The frontal sinus of the newborn is absent, from the first year of life it begins to develop, completing its formation by the age of 25. It is important to know that the posterior wall of the frontal sinus borders on the anterior cranial fossa, which is why it is possible to develop intracranial sinusogenic complications: meningitis, brain abscess, etc. The sphenoid sinus in the newborn has the appearance of a slit, and its formation, beginning at the age of 4-5, ends at the age of 20. However, at 12-14 years old it is already well pronounced.

What are the paranasal sinuses?

This question still remains without a definitive answer, although there are a lot of theories on this score. For example, it is believed that they serve as resonators of sound, reduce the mass of the skull, increase the surface of the olfactory area, soften the blows to the face, improve the hydration and warming of the inhaled air, regulate intracavitary pressure, etc.

Recently (especially in connection with the development of modern endoscopic surgery), much attention is paid to the study of transport of mucus from the sinuses through natural openings, the so-called clearance. The paranasal sinuses are lined with ciliated cylindrical epithelial cells, goblet and mucous glands that produce secretions. For the normal evacuation of this secret mechanism for its transportation should function well. However, this mechanism is often disturbed by air pollution, its increased dryness, disturbances of parasympathetic innervation, not to mention the toxic effect of microorganisms.

Particular importance in the occurrence of acute sinusitis in children have acute respiratory and infectious diseases. At the same time, there are factors contributing to the occurrence of sinusitis. These include chronic hypertrophic rhinitis, curvature of the nasal septum, spines, polyposis of the nose and especially adenoid vegetations. Significantly more acute sinusitis is found in children with allergic rhinitis, as well as with a reduced level of immunity, often suffering from acute respiratory infections. Acute inflammation of the maxillary sinus can be of odontogenic origin, associated with a fungal infection, trauma, etc.

Recently, in connection with the development of modern endoscopic surgery, much attention is paid to the study of transport of mucus from the paranasal sinuses through natural anastomoses, the so-called mucociliary clearance. The paranasal sinuses, similar to the nasal cavity, are lined with a ciliated epithelium, in its normal operation, the glands and secret produced by them are also involved. When air pollution, its increased dryness, parasympathetic innervation disorders, as well as under the influence of toxins of pathogenic microorganisms, the normal functioning of mucociliary clearance is disrupted, which leads to the development of sinusitis.

Especially it is necessary to stop on such a serious disease as osteomyelitis of the upper jaw. It develops in newborns, often the infection is transmitted by contact with an infected mother's nipple, contaminated toys. Consistently there is gingivitis, then the tooth rudiment and maxillary bone are involved in the process. Segments and fistulas are formed in the alveolar process. One-sided infiltration of the face is rapidly developing, closing the eye, swelling of the lower eyelid, chemosis. The disease is differentiated with dacryocystitis, erysipelas, endophthalmitis. The risk of osteomyelitis of the upper jaw is the possibility of developing septicemia. Treatment is complex, wide-spectrum antibiotics are used, good drainage is provided surgically, but in this case it is important not to damage the rudiments of the teeth.

Pathogenesis of sinusitis

In acute catarrhal inflammation, the mucous membrane thickens dozens of times, up to the filling of the entire lumen of the sinus. Characteristic serous impregnation and a sharp mucosal edema, cellular infiltration, dilated vessels, accumulation of exudate with the formation of extravasates. For acute purulent inflammation is characterized by purulent overlays on the surface of the mucous membrane, hemorrhage, hemorrhage (with influenza), severe circular cell infiltration. Possible processes of periostitis and osteomyelitis, up to sequestration.