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  • Cynthia M. Johnson, MA
Publication Type:




Peritonitis is inflammation of the peritoneum. This is the thin tissue that covers the inside of the abdomen. It also covers the outside of the intestines and other abdominal organs.

There are three types:

  • Primary (Spontaneous Bacterial Peritonitis)
  • Secondary
  • Dialysis-related

This health problem needs care right away. It can be deadly.


Peritonitis is caused by infection. Common causes are:

  • Primary—fluid buildup in the abdomen (ascites) becomes infected. Ascites is caused by health problems, such as cirrhosis of the liver .
  • Secondary—bacteria enters the belly due to an injury or health problem, such as a ruptured appendix.
  • Dialysis-related—bacteria enters the peritoneal cavity during or after peritoneal dialysis to treat kidney disease.
Secondary Peritonitis.

Nucleus factsheet imagehttp://services.epnet.com/getimage.aspx?imageiid=49214921exh39886d.jpgexh39886d.jpgNULLjpgBurst appendixNULL\\filer01a\Intellect\images\exh39886d.jpgNULL18NULL2003-04-16360390Copyright © Nucleus Medical Media, Inc.

Risk Factors

Things that may raise the risk of peritonitis are:


Problems may be:

  • Belly pain that is worse when moving
  • Bloating
  • Digestive symptoms, such as:
  • Fever
  • Lack of energy
  • Lightheadedness
  • Shortness of breath or fast heartbeat
  • Passing less urine (pee)


The doctor will ask about symptoms and past health. A physical exam will be done.

Blood tests will be done.

Fluid may be taken from the peritoneum for testing. This can be done with paracentesis .

Images may be taken of the abdomen. This can be done with x-rays and CT scans.

Surgery may be done to look inside the abdomen. This can be done with laparotomy .


The underlying cause will need to be treated. This may involve things like surgery to remove a ruptured appendix.

The goal of treatment is to ease the inflammation. Antibiotics or antifungal medicine will be given by mouth or IV to treat infection.


Antibiotics may be given to prevent spontaneous bacterial peritonitis if a person has:

  • Cirrhosis with:
    • Bleeding in the digestive tract
    • Low protein in the ascitic fluid
    • Reduced kidney function
    • Severe liver disease
  • A past episode of spontaneous bacterial peritonitis




  • Marciano S, Díaz JM, et al. Spontaneous bacterial peritonitis in patients with cirrhosis: incidence, outcomes, and treatment strategies. Hepat Med. 2019;11:13-22.
  • Secondary bacterial peritonitis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/secondary-bacterial-peritonitis.
  • Spontaneous bacterial peritonitis. EBSCO DynaMed website. Available at: https://www.dynamed.com/condition/spontaneous-bacterial-peritonitis.
  • Spontaneous bacterial peritonitis (SBP). Merck Manual Professional Version website. Available at: http://www.merckmanuals.com/professional/hepatic-and-biliary-disorders/approach-to-the-patient-with-liver-disease/spontaneous-bacterial-peritonitis-sbp.


  • Daniel A. Ostrovsky, MD
Last Updated:

This content is reviewed regularly and is updated when new and relevant evidence is made available. This information is neither intended nor implied to be a substitute for professional medical advice. Always seek the advice of your physician or other qualified health provider prior to starting any new treatment or with questions regarding a medical condition.