Encyclopedia / P / Peritonitis



Peritonitis is a serious disorder caused by an inflammation of the peritoneum, most often due to a bacterial infection.

The peritoneum is a two-layered membrane that lines the abdominal cavity and encloses the stomach, intestines, and other abdominal organs. The membrane supports the abdominal organs and protects them from infection. However, occasionally the peritoneum itself may become infected by bacteria or other organisms.


Infection usually spreads from organs within the abdomen. The inflammation may affect the entire peritoneum, or be confined to a walled-off, pus-filled cavity (abscess).

A rupture anywhere along the gastrointestinal tract is the most common pathway for entry of an infectious agent into the peritoneum.

Peritonitis is a medical emergency: the muscles within the walls of the intestine become paralyzed and the forward movement of intestinal contents stops (ileus).


Bacterial invasion results in infection and inflammation and perforation of the GI tract. Usually, this is a complication of appendicitis, diverticulitis, peptic ulcer, ulcerative colitis, strangulated obstruction, abdominal neoplasm, or a stab wound.

Peritonitis may also result from chemical inflammation, as in rupture of fallopian tubes or the bladder, perforation of a gastric ulcer, or released pancreatic enzymes.


Major symptoms of peritonitis are:

  • Acute onset of severe, steady pain throughout the abdomen or localized in one area. Pain may persist for several hours and is worsened by movement or pressure on the abdomen
  • Board-like rigidity of the abdomen, due to contraction of the muscles of the abdominal wall
  • Swollen or bloated abdomen
  • Chills and fever, with profuse perspiration
  • Nausea and vomiting
  • Weakness
  • Pale, cold skin
  • Shock


Diagnosis is based upon a clinical history compatible with peritonitis, and an exam in which the abdomen is tender to touch. In addition to pain, the abdomen is rigid and usually bowel sounds are absent.


Early treatment of GI inflammatory conditions and preoperative and postoperative antibiotic therapy help prevent peritonitis. Once peritonitis develops, emergency treatment is needed to combat infection, restore intestinal motility, and replace fluids and electrolytes.

Massive antibiotic therapy usually includes administration of cefoxitin with an aminoglycoside or penicillin G and clindamycin with an aminoglycoside, depending on the infecting organisms.

To decrease peristalsis and prevent perforation, the patient should receive nothing by mouth; instead, he should receive supportive fluids and electrolytes parenterally.

Surgery is often necessary when peritonitis is due to a disorder that has caused perforation along the intestinal tract, for example, a peptic ulcer or a burst appendix.

Analgesics may be administered to reduce pain.


Is the diagnosis peritonitis?

What is the likely cause?

Will surgery be required?

Is it likely to recur?