Definition

Peritonitis is inflammation of the peritoneum, the membrane that lines the abdominal cavity and covers the internal organs. It is commonly caused by a bacterial or fungal infection. There are two main types:

• Primary Peritonitis (Spontaneous Bacterial Peritonitis - SBP). This occurs when fluid in the abdominal cavity (ascites) becomes infected without any other apparent cause within the abdomen.
• Secondary Peritonitis. This results from inflammation or infection in abdominal organs that goes untreated and leads to rupture (perforation), spreading infection to the peritoneum.

Peritonitis is a medical emergency requiring immediate treatment, typically involving antibiotics and possibly surgery. If left untreated, peritonitis can lead to life-threatening infections.

Causes

Peritonitis can result from a variety of conditions, often due to rupture of an abdominal organ caused by untreated inflammation or infection. Some common causes include:

• Ruptured appendicitis or intestinal perforation: When the intestines or appendix burst, bacteria can enter the peritoneum through the resulting hole.
• Peptic ulcers: These are sores in the stomach lining that can perforate and spread infection.
• Pancreatitis: Inflammation of the pancreas may lead to the spread of bacteria outside the pancreas.
• Diverticulitis: Infection of small pouches in the digestive tract, known as diverticulosis, can cause peritonitis if one pouch bursts.
• Trauma: Injury to organs can lead to tears and contamination of the peritoneum.
• Medical procedures: Certain medical interventions can cause peritonitis, such as:
  • Peritoneal dialysis: Infection can occur if the dialysis equipment becomes contaminated.
  • Digestive tract surgery 
  • Feeding tubes: If feeding tubes are not regularly changed, they can become breeding grounds for bacteria, increasing infection risk.
  • Procedures to remove fluid from the abdominal cavity (ascites).
  • Complications from colonoscopy or endoscopy, though rare, can also result in peritonitis.

In some rare cases, peritonitis may develop without the rupture of any abdominal organs. This form, known as primary peritonitis or spontaneous bacterial peritonitis, is often a complication of liver disease, particularly cirrhosis. Severe liver failure can cause fluid accumulation in the abdomen, which is prone to bacterial infection.

Risk Factor

Certain factors can increase the likelihood of developing peritonitis, including:

• Undergoing medical procedures
• Having pre-existing medical conditions, such as liver failure, appendicitis, Crohn's disease, stomach ulcers, diverticulitis, or pancreatitis
• A history of previous peritonitis, as having had it once increases the risk of recurrence.

Symptoms

Signs and symptoms of peritonitis include:

• Abdominal pain or tenderness
• Bloating or feeling of fullness in the abdomen
• Fever
• Nausea and vomiting
• Loss of appetite
• Diarrhea
• Low urine output
• Thirst
• Inability to pass stool or gas
• Fatigue
• Confusion

For those undergoing peritoneal dialysis, additional symptoms may include:

• Cloudy dialysis fluid
• White spots or clumps in the dialysis fluid

Diagnosis

To diagnose peritonitis, your doctor will usually ask about:

• Your symptoms
• Medical history
• Any prior medical procedures

A physical examination, especially of the abdomen, is commonly performed. In patients on peritoneal dialysis, symptoms like cloudy dialysis fluid may be enough to diagnose peritonitis.

For primary and secondary peritonitis, doctors may also perform additional tests:

• Blood tests. Increased white blood cell counts can indicate infection.
• Blood culture. Determines if bacteria are present in the bloodstream, although results take time.
• Imaging tests. X-rays can reveal digestive tract perforations. Ultrasound and CT scans may also be used to assess the condition of the abdomen.
• Peritoneal fluid analysis. A needle is used to extract fluid from the peritoneum. High white blood cell counts suggest infection, and culturing the fluid can detect bacteria.

Management

Both primary and secondary peritonitis are life-threatening and require hospitalization. Treatment includes antibiotics and supportive care. For secondary peritonitis, treatment may include:

• Antibiotics: The type and duration depend on the severity and type of infection.
• Surgery: Often necessary to remove infected tissue, treat the underlying cause, and prevent the spread of infection, especially if caused by a ruptured appendix, stomach, or colon.
• Other treatments: These may include pain medication, IV fluids, oxygen, or blood transfusions as needed.

For patients on peritoneal dialysis, your doctor may suggest switching to a different form of dialysis temporarily until the infection is resolved. If peritonitis recurs, a permanent change to another type of dialysis may be needed.

Complications

Without timely treatment, peritonitis can lead to sepsis, a life-threatening condition where the infection spreads throughout the body. Sepsis can cause organ damage and even death.

Complications from secondary peritonitis may include:

• Abscesses in the abdominal cavity
• Intestinal tissue death (gangrene)
• Adhesions of abdominal organs, leading to intestinal obstruction
• Septic shock, where blood pressure drops dangerously low due to infection

Prevention

Peritonitis from peritoneal dialysis is often caused by germs around the catheter. If you are undergoing peritoneal dialysis, follow these steps to reduce the risk of peritonitis:

• Wash your hands before handling the tube. Use soap and running water, making sure to clean under your nails and between your fingers.
• Clean the skin around the catheter daily with an antiseptic liquid.
• Store dialysis equipment in a clean, hygienic area.
• Wear a surgical mask, especially during dialysis fluid exchanges, as germs from coughing or sneezing can enter the catheter tube.
• Consult your dialysis care team to discuss proper catheter care with your doctor and healthcare team.

If you’ve had peritonitis before or have a condition that could cause fluid buildup in the abdominal cavity, your doctor may prescribe antibiotics to help prevent future episodes of peritonitis.

When to See a Doctor?

Peritonitis can be life-threatening if not treated promptly. Seek immediate medical care if you experience severe abdominal pain or bloating along with:

• Fever
• Nausea and vomiting
• Low urine output
• Inability to pass stool or gas

For those undergoing peritoneal dialysis, contact your healthcare provider immediately if your dialysis fluid:

• Appears cloudy or discolored
• Contains white spots or lumps
• Has an unusual odor, particularly if the area around the catheter is red or tender

Additionally, peritonitis can result from a ruptured appendix or abdominal injury. Seek immediate medical care if you experience severe abdominal pain that prevents you from sitting still or finding a comfortable position. Call 911 or go to the emergency room if you have severe abdominal pain following an accident or injury.

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