The following symptoms occur in local inflammation. Increased heat in the part is an important symptom. It is due to the increased blood-flow to the part. Because of the pigmented, hairy skin of domestic animals, redness is of little value in locating superficial inflammation. Swelling is a valuable local symptom. It is produced by the inflammatory exudates. Pain results from the pressure on the sensory nerves by the inflammatory swelling. For example, the laminae of the foot are imprisoned between the horny wall and the pedal bone. This structure is well supplied with sensory nerves, and when it becomes inflamed and swollen, the tissues are subject to severe pressure and the pain is severe. Inflammation of a tendon results in lameness; of the udder, in suspension of milk secretions; and of the stomach by interference with digestion of the feed. Such symptoms may be grouped under the head of disturbed functions.
The character of an inflammation is largely modified by the nature of the tissue in which it occurs. A serous inflammation is characterized by serous, watery exudates. This form occurs in the serous membranes, mucous membranes and skin. Blisters on the skin and inflammation of bursae (capped hock and shoe boil) are examples of this type. Sero-fibrinous inflammations, such as occur in pleurisy and peritonitis, are common. Chronic inflammation commonly results in new formations of tissue, and it is named according to the character of the new tissue formed, as ossifying, adhesive, and fibrous inflammation. Pus-forming bacteria produce suppurative inflammation. Such diseases as tuberculosis, glanders and hog-cholera are specific inflammations. Specific infectious diseases may be classed as generalized inflammation, as they usually involve the entire body.
Inflammation terminates in resolution when the serum is reabsorbed by the blood-vessels and lymphatics, the living blood-cells find their way back into the circulation and the dead cells disintegrate and are taken up by the vessels. The time required for the tissues to return to the normal varies from a few hours to several weeks. An acute inflammation may end in the chronic form. This may then terminate in new formations, such as adhesions, fibrous thickenings and bony enlargements. Severe inflammation, especially if localized and superficial, may result in death of the part or gangrene.
The following treatment is recommended: The cause of the irritation to the tissue must be removed. It is very essential that the part be rested. The necessary rest may be obtained in different ways. Inflamed tendons, ligaments, and muscles may be rested by placing the animal in a sling, standing it in a stall, or fixing the part with bandages. Rest of the stomach or intestinal tract may be obtained by feeding a light diet, or withholding all feed. Comfortable quarters, special care and dieting the animal are important factors in the treatment of inflammation.
The agents used in the treatment of superficial and localized inflammation are heat, cold, massage and counterirritation. Heat is indicated in all inflammations, excepting when of bacterial origin. It stimulates the circulation and reabsorption of the inflammatory exudates, and by relaxing the tissues helps greatly in relieving pain. Cold is more effective in the highly acute and septic (suppurative) inflammation. Its action consists principally in the contraction of the dilated blood-vessels. Continuous irrigation of the part with cold water is the most satisfactory method of applying cold. Massage is a very important method of treating superficial inflammation. Mild, stimulating liniments are usually used in connection with hand-rubbing or friction. Chronic inflammation is usually treated with counterirritants. Blistering and firing are the most important methods of treatment. Such counterirritation makes possible the absorption of the inflammatory exudates by changing the chronic inflammation to the acute form.
WOUNDS.—A wound, in the restricted sense that the term is commonly used, includes only such injuries that are accompanied by breaks or divisions of the skin and mucous membrane. It is usually an open, hemorrhagic injury.
If the tissues are severed by a sharp instrument and the edges of the wound are smooth, it is classed as an incised or clean-cut wound. This class is not commonly met with in domestic animals outside of operative wounds.
When the tissues are torn irregularly, the injury is classed as a lacerated wound. A barb-wire cut is the best example of this class.
A contused wound is an injury caused by a blunt object. Such injuries may be divided into superficial and deep. Superficial-contused wounds may be an abrasion to the skin or mucous surface. Deep-contused wounds may be followed by loss of tissue or sloughing, and may present irregular, swollen margins. Such injuries are commonly caused by kicks.
Punctured wounds are many times deeper than the width of the opening or break in the skin or mucous membrane. This class is produced by sharp objects, such as nails, splinters of wood, and forks.