What are the differences between perforation and peritonitis?

Peritonitis refers to inflammation of the membrane (peritoneum) that lines the inside of the abdomen and surrounds the abdominal organs. Peritonitis can be caused by a bacterial infection when there is a leak or hole (perforation) in the stomach or intestines. Sometimes the bacterial infection happens without an identified leak or hole. Rarely, there can be inflammation of the peritoneum without an actual infection.