Inflammation of the peritoneum (seeabdominal cavity), with pus accumulating between the parietal and the visceral peritoneum, abdominal pain and distension, vomiting, and fever. It may be acute or chronic, local or generalized. Acute peritonitis usually results from inflammation elsewhere (e.g., by spread of bacterial infection). Primary peritonitis often comes from a perforated gastrointestinal tract, as with rupture in appendicitis. Control of the source problem may be followed by remission, adhesions, or abscesses (much rarer since the development of antibiotics).