Updated 25 April 2017


Peritonitis is an inflammation of internal organ membranes.


Alternative names

Abdominal cavity inflammation

What is peritonitis?

Peritonitis is an inflammation of the peritoneum, the membrane that lines the abdominal cavity and internal organs. The condition can be life-threatening if not identified and treated promptly.

There are three types of peritonitis:

  • Spontaneous peritonitis
  • Secondary peritonitis
  • Dialysis-associated peritonitis

What causes peritonitis?

Spontaneous peritonitis is caused by an infection in the blood that occurs when irritant fluid accumulates in the space between the layers of the peritoneum. This is most commonly one of the complications of cirrhosis, especially alcoholic cirrhosis. However, it is also sometimes related to peptic ulcer disease, appendicitis or diverticulitis.

Secondary peritonitis is a chronic or acute inflammation caused by bacteria entering the peritoneum following perforation of the gastrointestinal tract (for example, ruptured appendix). The irritant can be gastric juice, small bowel contents or faeces from the colon.

Dialysis-associated peritonitis occurs in people receiving peritoneal dialysis for chronic renal failure. This occurs secondary to infection around the catheter used for the dialysis.

Who gets peritonitis and who is at risk?

Adults who develop cirrhosis (chronic liver disease) as a result of alcohol abuse run the biggest risk of developing spontaneous peritonitis, but the incidence of the disease - even among adults - is very low. It is extremely rare in children. Any other condition which results in leakage of infectious fluids into the peritoneal cavity (such as a burst appendix) is a risk.

Some adults and newborn babies and infants with the disease necrotising enterocolitis, in which intestinal tissue dies off, are at risk of developing secondary peritonitis if preventative measures are not taken.

Patients with kidney failure requiring peritoneal dialysis are at risk of dialysis-associated peritonitis.

Symptoms and signs of peritonitis

Symptoms and signs of peritonitis may include the following:
  • Fluid accumulation in the abdomen – may indicate spontaneous, secondary or dialysis-associated peritonitis.
  • Abdominal distention – spontaneous, secondary, dialysis-associated.
  • Abdominal pain – spontaneous, secondary, dialysis-associated.
  • Point tenderness (pain in places) - spontaneous.
  • Difficulty in passing faeces or gas – spontaneous, secondary.
  • Low urine output – spontaneous, secondary.
  • Nausea and vomiting – spontaneous, dialysis-associated.
  • Thirst – spontaneous, secondary.
  • Fever or chills – spontaneous, secondary, dialysis-associated.
  • Signs of shock – secondary.

In the case of dialysis-associated peritonitis, the dialysed fluid that is returned from the peritoneal cavity becomes cloudy due to infection and puss cells.

How is peritonitis diagnosed?

Initial diagnosis is based on your symptoms and a physical examination. Your abdomen will be tender, and often distended. People with peritonitis will often feel the need to protect their abdominal area from touch. Once an initial diagnosis and assessment of the probably causes has been made, tests are carried out.

Tests for spontaneous and secondary peritonitis include:

  • Culture of peritoneal fluid (which is found in the peritoneal cavity and acts as a lubricant between the layers of the peritoneum) – a bacteriological laboratory test to identify infectious organisms in the fluid.
  • Chemical examination or laboratory analysis of peritoneal fluid.
  • Blood culture to determine the presence of micro-organisms in the blood.

Low blood pressure and rapid heart rate may indicate secondary peritonitis, and a gram stain (bacteriological stain of tissue fluids) together with a peritoneal fluid culture may be performed if dialysis-associated peritonitis is suspected.

Other possible tests for peritonitis, especially spontaneous peritonitis, include:

  • An abdominal X-ray to rule out other possible reasons for symptoms such as abdominal pain.
  • Surgery to open and examine the interior of the abdomen (called exploratory laparotomy).
  • A WBC nuclear scan, in which white blood cells are tagged with radioactive material so that they can be tracked when they migrate to infected or inflamed areas.

Can peritonitis be prevented?

Prevention of peritonitis is not usually within the control of the individual once they have conditions that predispose to this disease. However, following a healthy lifestyle can help to prevent these conditions, which in turn lessens the risk for developing peritonitis.

Medical professionals can help prevent dialysis-associated peritonitis through following careful medical procedure when performing peritoneal dialysis.

How is peritonitis treated?

The main goal of treating peritonitis is to cure the infection. The treatment method used depends on the source of the infection and the type of peritonitis present.

Spontaneous peritonitis: The most common treatment is by injection of antibiotics into the peritoneum to control the infection, together with drainage of the area. Surgery is only used to repair a perforation, such as in the rare case when peritonitis is caused by a rupture of an intra-abdominal organ, such as in the case of appendicitis.

Secondary peritonitis often requires surgical treatment to remove or repair the source of the infection, such as an abscess or an infected bowel. This is accompanied by bed rest, and intravenous antibiotics. Broad spectrum antibiotics are used to combat the infection until lab results indicate which treatment method is safest and best for the patient.

Dialysis-associated peritonitis is treated using antibiotics specific to the infectious organism or organisms found through analysis of cultures, blood or peritoneal fluid.

What is the outcome of treatment for peritonitis?

The sooner treatment is begun, the better your chances of recovery from any type of peritonitis.

In the case of spontaneous peritonitis, chances of full recovery are guarded due to the underlying cause (such as serious liver disease). Complications may include:

  • Abscess development
  • Bowel obstruction caused by scar tissue
  • Acute renal failure
  • Damage to the brain and nervous system due to complications of septic shock.

People with secondary peritonitis may recover completely if treatment begins soon enough; however, the disorder can be lethal in some cases. Complications may include:

  • Septic shock (cardiovascular collapse following serious infection in the blood) as a result of insufficient blood flow to vital organs and the heart.
  • Abscess development
  • Development of fibrous intraperitoneal scar tissue (intraperitoneal adhesions) i.e. within the peritoneal cavity.

Most people recover from dialysis-associated peritonitis without complications, however there is a risk of :

  • Recurrence
  • Abscesses and adhesions
  • Catheter tract infections that requires removal of the dialysis catheter

When to call the doctor

Contact your doctor or go to hospital immediately if you have any of the symptoms of peritonitis. Failure to treat peritonitis fast enough could result in a life-threatening situation.

Reviewed by Prof Don du Toit (M.B.Ch.B) (D.Phil.) (Ph.D) (FCS) (FRCS).


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