Peritonitis, i.e., inflammation of the peritoneum, may attack any of the domesticated animals. It must, however, be regarded as an almost accidental and relatively infrequent disease. It is due to infection of very varying character, and from the clinical standpoint may assume one of two forms—acute peritonitis or chronic peritonitis.
ACUTE PERITONITIS.
The microorganisms which produce peritonitis have not been the subject of special investigation in the domesticated animals, though the colon bacillus and streptococci, so frequently found in the female genital tract after parturition, seem to be the most frequent causative agents. Certain putrefactive organisms may also bring about the disease.
The peritoneum may become infected, and acute peritonitis ensue under various circumstances.
All operations in which the peritoneal cavity is opened, such as castration of the cow and of the sow, laparotomy, gastrotomy, enterotomy, etc., may be followed by acute peritonitis if performed without sufficient regard to aseptic precautions. Peritonitis then usually assumes an acute septic form.
Even simple puncture of the rumen, though usually quite harmless if carefully performed, may by followed by local or general peritonitis should food material escape from the rumen and find its way into the peritoneal cavity.
One of the most frequent causes is infection from the genital tract soon after parturition. Here the agents of infection are not introduced directly into the cavity, but find their way there in consequence of a diseased condition of the mucous membrane and the uterine walls. Ascending infections of this character and infections by contiguity of tissue may only give rise to local peritonitis, though in too many instances they become generalised.
Acute peritonitis may follow infection from the stomach or bowel, should a foreign body perforate the rumen or reticulum and pass backwards towards the peritoneal cavity, or a serious intestinal inflammation (enteritis, invagination, etc.) facilitate the passage of microbes through the thickness of the intestinal wall.
Abscess of the liver, suppurative echinococcosis, renal infection, pyelo-nephritis, acute cystitis, rupture of the bladder, etc., may in a similar way become complicated with acute peritonitis.
Finally, abdominal wounds may cause interstitial ruptures and lesions in the serous membrane, accompanied by local exudation (kicks, horn-thrusts, blows from cart-poles, etc.), and if microbic agents are brought within the region of the lesion by the general circulation or otherwise, peritonitis may follow.