Definition

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

Alternative Names

Acute abdomen; Spontaneous bacterial peritonitis; SBP; Cirrhosis - spontaneous peritonitis

Causes

Peritonitis is caused by a collection of blood, body fluids, or pus in the belly (abdomen).

One type is called spontaneous bacterial peritonitis (SBP). It occurs in people with ascites. Ascites is the buildup of fluid in the space between the lining of the abdomen and the organs. This problem is found in people with long-term liver damage, certain cancers, and heart failure.

Peritonitis may be a result of other problems. This is known as secondary peritonitis. Problems that may lead to this type of peritonitis include:

• Trauma or wounds to the belly
• Ruptured appendix
• Ruptured diverticula
• Infection after any surgery in the belly

Symptoms

Your belly is very painful or tender. The pain may become worse when your belly is touched or when you move.

Your belly may look or feel bloated. This is called abdominal distention.

Other symptoms may include:

• Fever and chills
• Passing little or no stools or gas
• Excessive fatigue
• Passing less urine
• Nausea and vomiting
• Racing heartbeat
• Shortness of breath

Exams and Tests

Your health care provider will perform a physical exam. The abdomen is usually tender. It may feel firm or board-like. People with peritonitis usually curl up or refuse to let anyone touch the area.

Blood tests, x-rays, and CT scans may be done. If there is a lot of fluid in the belly area, your provider may use a needle to remove some and send it for testing.

Treatment

The cause must be identified and treated right away. Treatment typically involves surgery, antibiotics, or both.

Possible Complications

Peritonitis can be life threatening and may cause complications. These depend on the type of peritonitis.

When to Contact a Medical Professional

Go to the emergency room or call 911 or the local emergency number if you have symptoms of peritonitis.

References

Bush LM, Levison ME. Peritonitis and intraperitoneal abscesses. In: Bennett JE, Dolin R, Blaser MJ, eds. Mandell, Douglas, and Bennett's Principles and Practice of Infectious Diseases. 9th ed. Philadelphia, PA: Elsevier; 2020:chap 74.

Kuemmerle JF. Inflammatory and anatomic diseases of the intestine, peritoneum, mesentery, and omentum. In: Goldman L, Cooney KA, eds. Goldman-Cecil Medicine. 27th ed. Philadelphia, PA: Elsevier; 2024:chap 128.