Peritonitis is an inflammation (irritation) of the peritoneum, the tissue that lines the wall of the abdomen and covers the abdominal organs.

A collection of pus in the abdomen, called an intra-abdominal abscess, may cause peritonitis.

See the specific types of peritonitis:

• Peritonitis - spontaneous
• Peritonitis - secondary
• Peritonitis - dialysis associated

• Abdominal pain or tenderness
• Abdominal distention
• Fever
• Low urine output
• Nausea and vomiting
• Point tenderness
• Thirst
• Fluid in the abdomen
• Inability to pass feces or gas

• Cloudy dialysis fluid (if undergoing peritoneal dialysis)
• Nausea and vomiting
• Shaking chills
• Signs of shock

The doctor will perform a physical exam. The abdomen is usually tender, and may feel firm and "board-like." The patient may extensively "guard" the area, using protective movements such as curling up or refusing to allow the area to be touched.

Blood tests, x-rays, and CT scans may be ordered.