Pyogenic infections of the soft tissues
Infections of the soft tissues around the jaws originate froma periapical infection related to a tooth or root,percoronal or periodontal infections or a secondary infected cyst or odontome.The infection causing organism may also enter the soft tissues from a penetrating wound with a retained foreign body which can be caused by a contaminated needle or a furuncle of the overlying skin.
The routes by which the infection can spread are:
1.By direct continuity through the tissues.
2.By the lymphatics to the regional lymphnodes and then in to the blood stream.If infection establishes itself in the lymphnodes then secondary abscesses may develop.
3.By the blood stream-Local thrombophlebitis may rarely propagate along the veins,entering the cranial cavity via emissary veins to produce cavernous sinus thrombophlebitis.Organism or infected emboli may be swept away in to the blood stream leading to bacteraemia,septicaemia and pyaemia with the development of embolic abscesses.
Factors affecting the ability of the infection to spread:
1.The type and virulence of the organisms.
2.A failure to drain accumulations of the pus.Pus contains large numbers of organisms and their toxins and drainage of an abscess usually leads within a matter of hours to a marked reduction in malaise and a fall in the patient’s temperature and pulse rate.
3.The state of the patient’s health generally which may de adversely affected by a virus infection,diabetes,malnutrition or alcoholism.
4.The ffectiveness of the patient’s immune mechanism.It takes time for the body’s immune mechanisms to be mobilized to combat an organism.
Anatomical factors influcencing direction of infection within the tissues:
1.The site of the source of the infection and the particular segment of the jaw involved.
2.The point at which the pus escapes from the bone and discharges in to the soft tissues.
3.The natural barrriers to the spread of pus in the tissues such as by layers of fascia or muscle or the jaw bones .