The Probert Encyclopaedia of Medicine

INFLAMMATION

The process by which tissues respond to injury or infection is known as inflammation. The term arose of course as a graphic description of the 'fieriness' of the tissues in this condition. Everyone is familiar with classical symptoms and signs of inflammation. It is important to realise that the tissues respond both to injury and infection in a similar manner, although the response to infection is usually more dramatic and accompanied by a greater general effect on the patient. Infection and inflammation are not synonymous. The underlying change in inflamed tissue is the great increase in the amount of blood flowing into the area involved. The chemicals released by the damaged tissues produce dilatation of the arteries, veins and capillaries to such an extent that serum exudes from the capillaries into the tissues, producing oedema. This distension of the tissues with fluid - the inflammatory exudate - is the main factor producing pain in inflammation. Pain and swelling together result in loss of function. This local inflammatory reaction is the beginning of the healing process and is at the same time a means of defence
against infection. White blood cells appear at the site of inflammation in great numbers and are responsible for the local control of bacteria which may have gained entrance. The invading organisms or the poisons which they have produced are carried away from the site of inflammation, partly by the veins and partly by the lymphatic system. As infection travels up the lymphatic vessels, these too become involved in the inflammatory process (lymphangitis). The lymph glands to which these lymphatics drain will become similarly inflamed, large and tender (lymphadenitis). Where there has been injury without infection, in addition to the inflammation, poisonous substances are released from the damaged tissues and these circulate in the blood stream, producing a state of shock.
Research Inflammation