Manual of Surgery Volume First: General Surgery. Sixth Edition.

by Alexis Thomson; Alexander Miles

If, however, the reaction induced by the infection is insufficient to check the growth and spread of the organisms, or to inhibit their toxin production, local necrosis of tissue may take place, either in the form of suppuration or of gangrene, or the toxins absorbed into the circulation may produce blood-poisoning, which may even prove fatal.

Clinical Aspects of Inflammation.—It must clearly be understood that inflammation is not to be looked upon as a disease in itself, but rather as an evidence of some infective process going on in the tissues in which it occurs, and of an effort on the part of these tissues to overcome the invading organisms and their products. The chief danger to the patient lies, not in the reactive changes that constitute the inflammatory process, but in the fact that he is liable to be poisoned by the toxins of the bacteria at work in the inflamed area.

Since the days of Celsus (first century A.D.), heat, redness, swelling, and pain have been recognised as cardinal signs of inflammation, and to these may be added, interference with function in the inflamed part, and general constitutional disturbance. Variations in these signs and symptoms depend upon the acuteness of the condition, the nature of the causative organism and of the tissue attacked, the situation of the part in relation to the surface, and other factors.

The heat of the inflamed part is to be attributed to the increased quantity of blood present in it, and the more superficial the affected area the more readily is the local increase of temperature detected by the hand. This clinical point is best tested by placing the palm of the hand and fingers for a few seconds alternately over an uninflamed and an inflamed area, otherwise under similar conditions as to coverings and exposure. In this way even slight differences may be recognised.

Redness, similarly, is due to the increased afflux of blood to the inflamed part. The shade of colour varies with the stage of the inflammation, being lighter and brighter in the early, hyperæmic stages, and darker and duskier when the blood flow is slowed or when stasis has occurred and the oxygenation of the blood is defective. In the thrombotic stage the part may assume a purplish hue.

The swelling is partly due to the increased amount of blood in the affected part and to the accumulation of leucocytes and proliferated tissue cells, but chiefly to the exudate in the connective tissue—inflammatory œdema. The more open the structure of the tissue of the part, the greater is the amount of swelling—witness the marked degree of œdema that occurs in such parts as the scrotum or the eyelids.

Pain is a symptom seldom absent in inflammation. Tenderness—that is, pain elicited on pressure—is one of the most valuable diagnostic signs we possess, and is often present before pain is experienced by the patient. That the area of tenderness corresponds to the area of inflammation is almost an axiom of surgery. Pain and tenderness are due to the irritation of nerve filaments of the part, rendered all the more sensitive by the abnormal conditions of their blood supply. In inflammatory conditions of internal organs, for example the abdominal viscera, the pain is frequently referred to other parts, usually to an area supplied by branches from the same segment of the cord as that supplying the inflamed part.

For purposes of diagnosis, attention should be paid to the terms in which the patient describes his pain. For example, the pain caused by an inflammation of the skin is usually described as of a burning or itching character; that of inflammation in dense tissues like periosteum or bone, or in encapsuled organs, as dull, boring, or aching. When inflammation is passing on to suppuration the pain assumes a throbbing character, and as the pus reaches the surface, or “points,” as it is called, sharp, darting, or lancinating pains are experienced. Inflammation involving a nerve-trunk may cause a boring or a tingling pain; while the implication of a serous membrane such as the pleura or peritoneum gives rise to a pain of a sharp, stabbing character.

Interference with the function of the inflamed part is always present to a greater or less extent.

Constitutional Disturbances.—Under the term constitutional disturbances are included the presence of fever or elevation of temperature; certain changes in the pulse rate and the respiration; gastro-intestinal and urinary disturbances; and derangements of the central nervous system. These are all due to the absorption of toxins into the general circulation.