Peritonitis may be accompanied by pain that is typically severe and may occur in just one area of the abdomen or throughout the abdomen. In most cases, patients with inflammation caused by peritonitis will experience fever, vomiting and tenderness in the abdomen.

Other symptoms may include:

• Distension or rigidity of the abdomen
• Low urine output
• Loss of appetite
• Thirst
• Inability to pass feces or gas
• Increased breathing and heart rates or shallow breathing
• Low blood pressure
• Chills

Patients whose peritonitis is related to peritoneal dialysis treatment, in which wastes are artificially removed from the body after kidney failure, may notice an unusual color or cloudiness in their used fluid, or redness or pain around the catheter insertion site.  

Peritonitis that is not treated promptly may cause pus-filled areas of infection called abscesses to form inside the abdominal cavity. Infection associated with peritonitis can cause the development of scar tissue that obstructs the intestine. Peritonitis can also halt the process that pushes stool through the intestine (peristalsis) and can cause fluid to leak from the bloodstream into the abdominal cavity. Severe dehydration may cause the body to lose important electrolytes and may be followed by widespread blood clotting and lung, kidney and liver failure.