Peritonitis is an inflammation or infection of the peritoneum, a membrane that lines the abdominal cavity and organs. In most cases, peritonitis begins when bacteria in the bowel or digestive organs spread through a perforation (hole) into the abdominal cavity.

For example, bacteria may leak through a hole in the gastrointestinal tract due to a ruptured appendix, stomach ulcer or perforated colon. In other instances, biochemicals in the body may irritate the peritoneum and cause peritonitis. For example, pancreatic enzymes may leak into the peritoneum during a bout of pancreatitis.

Peritonitis may be primary (in which the source of contamination is not known) or secondary (in which contamination is caused by a condition, such as appendicitis). A third type of peritonitis can develop in patients undergoing certain types of dialysis (the artificial removal of bodily wastes after kidney failure).

Symptoms associated with peritonitis include fever, vomiting and abdominal pain. Diagnosis of peritonitis typically includes physical examination of the abdomen, imaging studies and blood tests.

Peritonitis is a potentially life-threatening condition that demands immediate medical attention. When bacteria are identified as the source of infection or inflammation, antibiotics will typically be prescribed. In some cases, surgery may be performed to correct the source of the peritonitis, such as removing an inflamed appendix, infected bowel or abscess.