Peritonitis is inflammation of the peritoneum, the membrane that lines the abdominal cavity. It is a serious and often fatal condition. Peritonitis may be short- or longterm, localized or widespread. Most commonly it occurs due to contamination of the peritoneal cavity (for example by perforation of the abdominal cavity by a foreign object, ruptured bladder or gallbladder, the splitting open of an abdominal wound closure, or rupture of the intestine due to the presence of a swallowed foreign object), but it also may be caused by infectious agents such as viruses or bacteria that travel from the bloodstream to the peritoneum. For example, feline infectious peritonitis is thought to be caused by a mutated coronavirus.
Signs of peritonitis vary depending on the cause. Fever, blood poisoning, shock, reduced blood pressure, hemorrhage, severe abdominal pain, loss of appetite, depression, vomiting, paralytic obstruction of the intestines with reduced fecal output, and fluid accumulation within the abdominal cavity may all be signs of peritonitis. Rupture of the gastrointestinal tract, with spillage of large volumes of intestinal contents, leads to sudden, severe peritonitis. Death due to shock from the large amounts of bacterial toxins may occur suddenly.
A physical examination, abdominal ultrasound, x-rays, and blood tests may be used to diagnose peritonitis. Your veterinarian may also obtain a sample of abdominal fluid to help determine the cause and to plan treatments. The first priority of treatment is to stabilize the consequences of peritonitis, such as 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. Hospitalization with intravenous fluids or blood transfusions may be necessary to improve blood circulation.
Once the cat is stabilized, surgery may be necessary to explore the abdomen and to repair any defects. Antibiotics are continued after surgery. Nutritional support with intravenous feeding or a feeding tube may be needed, as many cats with peritonitis will not eat after surgery.
Peritonitis is considered a severe, life-threatening disease. Unfortunately, feline infectious peritonitis is a lethal disease with no effective longterm treatment. However, available treatments may help improve a cat's quality of life for a limited period of time. For cats with other causes of peritonitis, as many as 50–70% of patients may survive with prompt treatment.
Also see professional content regarding peritonitis.
