Rarely, it may occur with conditions such as rheumatoid arthritis, systemic lupus erythematosus, or pancreatitis. Peritonitis is most commonly caused by inflammation of an abdominal organ, perforation of a peptic ulcer or colonic diverticulum, or an inflamed appendix. The chief symptom is severe abdominal pain. The pain may be localized to one part of the abdomen. Usually there is a fever, accompanied by rapid pulse rate.
Vomiting often occurs as the result of the onset of a paralytic ileus.
The patient is hospitalized and treatment begins with intravenous antibiotics and other drugs, which are used to treat any infection and to control pain. Emptying of the stomach through a nasogastric tube is sometimes needed. A surgical operation is required if appendicitis or a ruptured peptic ulcer is found. If treatment is not started immediately, death may result. An abscess may form under the diaphragm or in the pelvis as a result of salpingitis.