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Pet Owner Version

Peritonitis in Dogs


Thomas Wittek

, Dr Med Vet, DECBHM, University Clinic for Ruminants, Department of Farm Animals and Veterinary Public Health, University of Veterinary Medicine, Vienna

Reviewed/Revised Jun 2018 | Modified Oct 2022

Peritonitis is inflammation of the membrane that lines the inside of the abdominal cavity (peritoneum). It is a serious and often fatal condition in dogs, with mortality ranging from 50% to 70%. Peritonitis may be short or longterm, localized or widespread. Most commonly it occurs due to contamination of the peritoneal cavity. Examples include perforation of the abdominal cavity by a foreign object, splitting open of an abdominal wound closure, rupture of the intestine due to the presence of a foreign object, rupture of the bladder or uterus, abdominal surgery, perforation of a stomach or intestinal ulcer, abdominal tumor, inflammation of the liver (hepatitis) or pancreas (pancreatitis), gall bladder rupture or disease, or gastric dilatation and volvulus ("flipped" stomach). Less frequently, peritonitis may be caused by infectious agents that spread from the bloodstream, such as viruses, parasites, fungi, or bacteria. Occasionally, peritonitis occurs due to unknown causes.

Fever, blood poisoning, shock, reduced blood pressure, bleeding, abdominal pain, paralytic obstruction of the intestines with reduced fecal output, vomiting, abdominal swelling, and fluid accumulation may all be signs of peritonitis. Rupture of the gastrointestinal tract, with spillage of large volumes of intestinal contents, leads to short-term peritonitis. Death due to shock from the large amounts of bacterial toxins may occur suddenly.

Veterinarians may suspect peritonitis based on physical examination findings, blood tests, and x-rays. To confirm peritonitis, they may extract and analyze a sample of abdominal fluid.

The first priority of treatment is to stabilize the consequences of peritonitis (for example, shock, changes in electrolytes, acid-base imbalance, fluid loss, and blood clotting abnormalities). In addition, your veterinarian will want to identify the point of origin of inflammation and correct or remove it. Antibiotics are a standard part of the treatment. Replacement fluids, electrolytes, plasma, or whole blood may be necessary to maintain heart output. Medication to reduce inflammation may also be given.

Once your pet is stabilized, surgery may be done to explore the abdomen and repair any defects. Your veterinarian will follow this with a thorough rinsing of the abdominal cavity to remove any irritating substances. Specialized drains are sometimes also placed at this time so that the abnormal fluid can continue to be removed after surgery. Antibiotics are continued after surgery. Nutritional support with intravenous feeding may be needed, as many animals with peritonitis will not eat after surgery. In animals with blood poisoning and shock, fluids, electrolytes, and antibiotics are crucial elements of treatment.

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