Peritonitis: Causes, Symptoms, Diagnosis & Treatment (2023)


What is peritonitis?

Your peritoneum is a thin membrane that lines the inside of your belly (abdomen) and wraps around the organs inside. Peritonitis is the term for inflammation of the peritoneum. The tissues can become inflamed if they’re exposed to irritating or infected body fluids. This usually happens when something inside leaks or breaks. Infection is the most common cause of peritonitis, and it can be very dangerous.

How does peritonitis affect my body?

Your symptoms may vary depending on the type of peritonitis you have. They usually include abdominal pain and swelling. But it’s the complications that you want to watch out for. Since your peritoneum spreads throughout your abdomen and touches many organs, infections in your peritoneum can affect all of these organs. It can also spread to your bloodstream and become systemic throughout your body.

Is peritonitis an emergency?

Peritonitis can be mild to severe, and it can be localized in one place or diffuse throughout your peritoneum. However, healthcare providers always treat peritonitis as an emergency because it can become severe very quickly, especially if it’s infectious. An infection that spreads to your bloodstream (septicemia) can cause your whole body to go into a kind of shock and shut down vital organs (septic shock).

Symptoms and Causes

Peritonitis: Causes, Symptoms, Diagnosis & Treatment (1)

What is the most common cause of peritonitis?

Bacterial infections are the most common cause, especially secondary infections that spread from one of your organs. This can happen if you have a hole in your stomach or intestines that lets bacteria from your gastrointestinal tract enter your peritoneal cavity. A burst appendix from appendicitis is another common cause. Less commonly, bacterial peritonitis can start in your peritoneum itself.

Chemical causes

Inflammation is often caused by an infection, but sometimes it’s just a chemical reaction to different body fluids. For example:

  • Bile can leak from your gallbladder if severe inflammation (cholecystitis) causes a perforation in the tissues. Bile can be irritating with or without bacterial infection.
  • Pancreatic enzymes can leak from your pancreas if severe inflammation (pancreatitis) causes a perforation in the tissues. These can be irritating with or without infection.
  • Stomach acid can leak from your stomach if an ulcer wears a hole all the way through. Gastric acid can irritate even without bacteria.
  • A tumor or cyst that ruptures in your abdomen can cause chemical peritonitis.

Infectious causes

Infectious peritonitis can be either primary or secondary. Primary infectious peritonitis is caused by an infection that originates in your peritoneum itself. Secondary bacterial peritonitis spreads to your peritoneum from somewhere else in your body.

Primary infection is less common than secondary infection. It usually happens in one of two ways:

  • Spontaneous bacterial peritonitis (SBP) develops in people with ascites. This is a condition of excess fluid from leaking veins that accumulates in your peritoneum. Ascites comes from diseases that compromise your immune system, including liver disease, kidney failure, heart failure and cancer. Some of these diseases can also allow small amounts of bacteria to penetrate from your gastrointestinal tract. Retained fluid that isn’t being filtered or cleared as usual, combined with reduced immunity, allows these trace amounts of bacteria to infect the peritoneum.
  • Primary infection can also be introduced to your peritoneal cavity by medical instruments, especially when you use them regularly at home. Dialysis and tube feeding are two ways this can happen. Peritoneal dialysis fills and drains your peritoneal cavity with fluid through a tube (catheter). Long-term tube feeding may pass a catheter directly through your peritoneum to your stomach or small intestine. This breach of organ walls can introduce an infection to the rest of the abdominal cavity.

Secondary infection is the most common cause of peritonitis. It can be caused by:

  • A burst appendix (appendicitis).
  • A perforated stomach ulcer (peptic ulcer disease).
  • A perforated intestinal ulcer from diverticulitis or inflammatory bowel disease.
  • Infectious pancreatitis.
  • A ruptured tubo-ovarian abscess from pelvic inflammatory disease.
  • A ruptured ectopic pregnancy.
  • Trauma or injury to your abdomen.
  • Abdominal surgery.

What are the signs and symptoms of peritonitis?

Typical symptoms include:

  • Mild to severe abdominal pain and sensitivity to touch.
  • Swollen, distended abdomen.
  • Dehydration.
  • Paralytic ileus (when your bowels are temporarily paralyzed).

If you have an infection, you may also have:

  • Fever.
  • Nausea and vomiting.
  • Fast heart rate.
  • Shortness of breath.

If you have ascites, you may also have:

  • Mild cognitive impairment (from hepatic encephalopathy).
  • Fatigue and malaise.
  • Swollen legs and feet (edema).
  • Easy bruising and bleeding (thrombocytopenia).

Can you have peritonitis and not know it?

Yes, it’s possible. Abdominal pain and other symptoms from the original condition that causes your peritonitis can disguise the symptoms of peritonitis itself. Some people have less sensation in their peritoneum if it’s been swollen with ascites for some time. They may not notice the difference if ascites becomes infected. It’s important for healthcare providers to stay alert to the risk of peritonitis.

Diagnosis and Tests

How is peritonitis diagnosed?

Your healthcare provider will begin by asking about your medical history and current conditions. They will physically examine your abdomen and check to see if it is swollen, sensitive to the touch or rigid. If it is, they will follow up with a blood test to check for evidence of inflammation or infection (high white blood cell count). They may also take images of your abdominal organs to look for causes of peritonitis.

One way to confirm and identify the specific infection in your peritoneum is to draw out some of the fluid with a needle (paracentesis) and test it in a lab (peritoneal fluid culture). In cases of ascites, this can also help relieve pressure in your abdomen. In more difficult cases, when your healthcare provider can’t find the cause of your peritonitis, they may need to explore your abdominal cavity in surgery to find and fix the problem.

Management and Treatment

What is the treatment for peritonitis?

Treatment typically begins with IV fluids and broad-spectrum antibiotics to treat or prevent infection. If later tests reveal the exact bacterium or pathogen causing your infection, you may be given a more specific antibiotic for it then. Your healthcare team will work to stabilize your condition before moving on to address the underlying cause. Some causes will require emergency surgery to repair.

Outlook / Prognosis

What are the possible complications of peritonitis?

Peritonitis can lead to:

  • Septicemia and sepsis, if the infection enters your bloodstream. Sepsis can lead to death.
  • Dehydration and electrolyte imbalances from the transfer of fluids to your abdomen.
  • Constipation and urine retention when your organs are temporarily paralyzed.
  • Abdominal adhesions, scar tissue from inflammation that may obstruct your bowels.
  • In those with liver disease, spontaneous bacterial peritonitis can trigger hepatorenal syndrome.
  • Tertiary peritonitis is an infection that comes back after the original cause has been treated.

What is the prognosis for people with peritonitis?

Your outlook depends on the cause and type of peritonitis you have and how quickly it’s treated. Early recognition is important to be able to control peritonitis before it becomes complicated. Treatment is usually effective, but some complications, such as organ damage, may be lasting. Those with weaker immune systems, due to various chronic diseases, are more at risk for complications than others.

A note from Cleveland Clinic

Peritonitis can develop very suddenly, and it’s important to act quickly when it does. Your symptoms and pain levels may or may not seem like an emergency. Abdominal pain can have many different causes, some more serious than others, but if you're in doubt, it doesn’t hurt to check. If you’ve had slowly building symptoms for a while and they suddenly get worse, seek medical attention right away.


What are 4 signs of peritonitis? ›

What are symptoms of peritonitis?
  • Severe belly pain that gets worse with any motion.
  • Nausea and vomiting.
  • Fever.
  • Sore or swollen belly.
  • Fluid in the belly.
  • Not being able to have a bowel movement or pass gas.
  • Less urine than normal.
  • Thirst.

What is the most common cause of peritonitis? ›

Secondary infection is the most common cause of peritonitis. It can be caused by: A burst appendix (appendicitis).

What is the main treatment for peritonitis? ›

Peritonitis treatment usually involves medicines that are used for infections caused by bacteria, called antibiotics. Some people with peritonitis need surgery. If you don't get treatment, peritonitis can lead to a serious infection that spreads through the body. It can be deadly.

What is the first indication of peritonitis? ›

The first symptoms of peritonitis are typically poor appetite and nausea and a dull abdominal ache that quickly turns into persistent, severe abdominal pain, which is worsened by any movement. Other signs and symptoms related to peritonitis may include: Abdominal tenderness or distention.

What are the 3 stage of peritonitis? ›

Stages of peritonitis

1) reactive (first 24 hours); 2) toxic (24-72 hours); 3) terminal (over 72 hours) with bacterial-septic shock and without it.

What are the red flags of peritonitis? ›

Peritonitis – acute pain with signs of shock, rebound tenderness and a rigid abdomen. Ruptured AAA – pain radiating to the back or groin, patient may be in shock, pulsatile mass present.

What organ does peritonitis affect? ›

Peritonitis is inflammation of the membranes of the abdominal wall and organs. Peritonitis is a life-threatening emergency that needs prompt medical treatment. The abdominal organs, such as the stomach and liver, are wrapped in a thin, tough membrane called the visceral peritoneum.

Where is peritonitis found in the body? ›

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. The peritoneum is the membrane lining the abdominal cavity.

How long does peritonitis last? ›

If you're diagnosed with peritonitis, you'll need treatment in hospital to get rid of the infection. This might take 10 to 14 days. Treatment usually involves being given antibiotics into a vein (intravenously).

Can you fully recover from peritonitis? ›

Peritonitis can be cured if treated properly within time. It is recommended that the treatment for this condition must begin immediately after being diagnosed, for effective results.

How many stages of peritonitis are there? ›

Peritonitis is divided into three stages. The division is based on the defensive and inhibitory mechanisms of the host.

Will a CT scan show peritonitis? ›

CT scans of the abdomen and pelvis remain the diagnostic study of choice for peritoneal abscess and related visceral pathology. Whenever possible, the CT scan should be performed with enteral and intravenous contrast.

Can you have peritonitis without knowing? ›

A person with peritonitis may not notice any symptoms but a doctor can detect the condition before symptoms become noticeable. During peritoneal dialysis for kidney disease, for example, a patient will be at risk of infection through the abdominal wall.

How do you confirm peritonitis? ›

Symptoms include abdominal discomfort, nausea and vomiting, loss of appetite, diarrhea, constipation, fever, fatigue, and confusion. Peritonitis can be diagnosed through a physical exam, blood test, peritoneal fluid analysis, or imaging studies.

How does a patient with peritonitis present? ›

Patients with severe peritonitis often avoid all motion and keep their hips flexed to relieve the abdominal wall tension. The abdomen is often distended, with hypoactive-to-absent bowel sounds. This finding reflects a generalized ileus and may not be present if the infection is well localized.

How long does it take for peritonitis to become fatal? ›

The infection stops the normal movements of the intestines (peristalsis). The body quickly becomes dehydrated, and important chemicals called electrolytes are dangerously disturbed. The internal organs – such as lungs, kidneys and liver – may fail. A person with untreated peritonitis can die within a few days.

What is the hallmark of peritonitis? ›

Abdominal pain represents the hallmark symptom of peritonitis. It can be continuous and different from tense ascites, and is often accompanied by tenderness as a common feature.

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