Peritonitis

Peritonitis is a serious inflammation of the tissue lining the inside of your belly that requires immediate medical attention and can become life-threatening without prompt treatment.

Table of contents

• What is peritonitis?
• Associated anatomy
• Types of peritonitis
• Signs and symptoms
• What causes peritonitis?
• Possible complications
• How is peritonitis diagnosed?
• Treatment options
• Preventing peritonitis
• Prognosis and survival rates

What is peritonitis?

Peritonitis is a serious condition that starts in the abdomen, which is the area of the body between the chest and the pelvis. It happens when the thin layer of tissue inside the abdomen becomes inflamed. This tissue layer is called the peritoneum, which is a thin, tough membrane that lines the inner wall of your abdomen and covers and supports most of your abdominal organs, such as the stomach and liver^[1][2].

Peritonitis usually happens due to an infection from bacteria or fungi. The peritoneum, which is normally a sterile environment, reacts to various harmful conditions with an inflammatory response. Depending on the underlying cause, the resulting peritonitis may be infectious or sterile, meaning it can be caused by chemical or mechanical irritation^[6].

This condition is a medical emergency that can cause life-threatening complications. If you don’t get treatment, peritonitis can lead to a serious infection that spreads through the body and can be deadly^[1][2].

• Abdomen
• Peritoneum
• Stomach
• Intestines
• Liver
• Pancreas
• Gallbladder
• Appendix

Types of peritonitis

Doctors divide peritonitis into several types based on how the infection starts and spreads^[5][6].

Spontaneous bacterial peritonitis (also called primary peritonitis) occurs when bacteria start growing in the abdominal lining without any obvious source inside the abdomen. This infection is caused by bacteria and happens most often when someone has liver disease, such as cirrhosis, or kidney disease. It is believed that infectious agents spread through the bloodstream or lymphatic system, particularly in people with weakened immune systems^[1][4]. Primary peritonitis is estimated to occur in 10% to 30% of patients with alcoholic cirrhosis^[12].

Secondary peritonitis is by far the most common form of peritonitis. It happens when an infection spreads to the lining from elsewhere in the body. This type can occur due to a hole, also called a rupture, inside an organ in the abdomen, or it can be caused by other health conditions. Secondary peritonitis is most commonly the result of gastrointestinal rupture, perforation, or breakdown in the surgical connection between organs^[4][5].

Tertiary peritonitis is persistent or recurrent infection that reappears at least 48 hours after apparent resolution of primary or secondary peritonitis. This less well-defined type is characterized by infections with organisms of low strength or with conditions that favor the immunocompromised patient. It usually follows surgical attempts to treat secondary peritonitis and is almost exclusively associated with widespread inflammatory response throughout the body^[6][13].

Chemical peritonitis (also called sterile peritonitis) can occur without an infection. Sometimes you can get peritonitis when irritating fluids leak from your gallbladder, pancreas, stomach, or elsewhere in your body. There are fluids in your body that are harmless when they stay where they belong, but they can cause inflammation if they end up in your peritoneum^[2][5].

Signs and symptoms

The first symptoms of peritonitis are often poor appetite, nausea, and a dull belly ache. The dull ache can quickly turn into persistent, severe abdominal pain that gets worse when you move. One common and serious symptom is a dull ache in your belly that suddenly becomes a sharp pain and doesn’t let up. The pain can be so intense that you can’t sit still^[2][5].

Symptoms of peritonitis include^[1][2][5]:

• Belly pain or tenderness
• Bloating or a swollen belly that’s tight and tender to the touch
• Fever and chills
• Inability to pass gas or stool (constipation)
• Nausea and vomiting
• Fatigue
• Fast heart rate
• Shortness of breath
• Trouble peeing or peeing much less than usual
• Thirst
• Deep, rapid breathing, dry tongue and lips, and other symptoms of dehydration
• Edema (swelling) in the legs and feet

Symptoms of paralytic ileus may also occur, which is temporary paralysis of your intestines^[2].

If you get peritoneal dialysis (a treatment for kidney failure), additional symptoms may include cloudy dialysis fluid or white flecks, strands, or clumps in the dialysis fluid^[1][5].

What causes peritonitis?

Bacterial infections are the most common cause of peritonitis. Some start in your peritoneum (primary infections), but most happen when a bacterial infection in a nearby organ spreads to your peritoneum. You may also develop peritonitis if fluid from nearby organs leaks into your peritoneum^[2].

Secondary infections

These infections happen when you have a condition that damages organs close to your peritoneum. Your damaged organs may release infected fluid that seeps into your peritoneum. This can happen if you have^[2][5][11]:

• Appendicitis that involves a burst appendix
• Diverticulitis or inflammatory bowel disease (such as Crohn’s disease) that causes holes in your gastrointestinal tract
• Fallopian tube rupture (ruptured ectopic pregnancy)
• Pelvic inflammatory disease involving a tubo-ovarian abscess that ruptures
• Peptic ulcer disease that makes a hole in your stomach
• Surgical site infection from abdominal surgery
• Traumatic injury to your belly that lets bacteria get into it
• Perforated gallbladder from severe cholecystitis

Primary infections

Primary infections start in your peritoneum. They usually happen in one of two ways^[2][11]:

• You have ascites (fluid buildup) in your peritoneum. Cancer in your belly, cirrhosis, or congestive heart failure can cause ascites
• You need medical treatment that can let bacteria into your peritoneal cavity. This can happen if you need peritoneal dialysis. Bacteria may also get into it if you’re receiving nutrition through a feeding tube

A common cause of peritonitis is peritoneal dialysis, which is a treatment for kidney failure that helps get rid of waste products from the blood when the kidneys struggle to do that job themselves. Patients on chronic ambulatory peritoneal dialysis have, on average, one incidence of peritonitis every 33 months^[1][12].

Chemical peritonitis

This can happen if you have conditions like^[2][11]:

• Pancreatitis that makes a hole in your pancreas, allowing pancreatic enzymes to flow through the hole into your peritoneum to cause inflammation
• Severe cholecystitis that causes a hole in your gallbladder, letting bile leak into your peritoneum
• Stomach ulcers that wear through the wall of your stomach, allowing stomach acid to get to your peritoneum

Possible complications

Severe inflammation in your peritoneum triggers a series of changes in your body that may cause sepsis. This is a life-threatening condition that can happen when your body has an extreme reaction to an infection^[2].

The inflammatory process results in fluid shifts into the peritoneal cavity. This fluid accumulation, along with decreased intestinal motility, often leads to abdominal swelling. Additionally, fluid displacement into the abdomen, known as third-spacing, may result in decreased blood volume, leading to hypovolemia (low blood volume) in severe cases^[12].

Peritonitis can also lead to the development of multiple organ dysfunction syndrome. Without treatment, the once-localized disease process can damage other organs throughout the body^[12].

How is peritonitis diagnosed?

To diagnose peritonitis, your healthcare professional talks with you about your medical history and gives you a physical exam. Your symptoms alone may be enough to diagnose the condition if your peritonitis is linked to peritoneal dialysis^[7].

If more tests are needed to confirm a diagnosis, your healthcare professional may suggest^[7]:

Blood tests. A sample of your blood may be taken to see if you have an increase in disease-fighting white blood cells. This is usually a sign of an infection or inflammation. You also might have a blood culture test to find out if bacteria are in your blood.

Peritoneal fluid analysis. In this test, a thin needle is used to take a sample of the fluid in your peritoneum. This is the preferred diagnostic method for confirming peritonitis. You’re more likely to have this test if you get peritoneal dialysis or if you have fluid in your abdomen from liver disease. An increased white blood cell count in this fluid usually points to an infection or inflammation. A culture of the fluid may be used to spot bacteria. When abdominal fluid examination reveals degenerative neutrophils and intracellular bacteria, confirming a diagnosis of septic peritonitis, emergency surgical exploration of the abdomen is indicated^[4][7].

Imaging tests. You may have an X-ray exam to check for holes or other tears in your digestive tract. You also may have a test that uses sound waves to make images inside your body, called ultrasound. In some cases, you may have a CT scan, which is a type of imaging test that creates detailed pictures of your internal organs^[7].

Treatment options

Spontaneous bacterial peritonitis can be life-threatening. You’ll need to stay in the hospital. Treatment includes antibiotics and supportive care to ease your symptoms. You’ll also need to stay in the hospital for secondary peritonitis^[7].

Antibiotics

You’ll likely take antibiotic medicine through a needle in a vein. This clears out the infection and keeps it from spreading. The type of antibiotic you’ll need and how long you’ll have to take it will vary. It depends on how serious the infection is and the type of peritonitis you have. Antibiotic therapy is a fundamental cornerstone of treatment. If you use peritoneal dialysis and the infection is minor, the medicine may be added to the dialysis fluid^[7][10].

The antibiotic treatment must include coverage for both aerobic bacteria (mostly Escherichia coli) and anaerobic bacteria (mostly Bacteroides fragilis) in its spectrum^[10].

Surgery

Some people with peritonitis need surgery. If part of your stomach lining has been seriously damaged by infection, you may need surgery to remove it. Sometimes pus-filled swellings (abscesses) develop in the lining and need to be drained with a needle under local anesthetic. You might also need an operation to deal with the cause of the peritonitis. For example, a burst appendix will need to be removed^[7][17].

Operative management addresses the need to control the infectious source and to purge bacteria and toxins. The type and extent of surgery depends on the underlying disease process and the severity of intra-abdominal infection. Definitive interventions to restore functional anatomy involve removing the source of the antimicrobial contamination and repairing the disorder causing the infection^[9].

Open peritoneal drainage or closed suction drainage should be considered for management of septic peritonitis in which the source of contamination cannot be controlled completely, or if significant contamination or inflammation remains after surgical cleaning and washing^[4].

Supportive care

It can be difficult to digest food if you have peritonitis. A feeding tube might be passed into your stomach through your nose or placed inside your stomach using keyhole surgery. If a feeding tube cannot be used, liquid nutrients can be given directly into one of your veins^[17].

Your dialysis team may decide to change the way you do dialysis. The doctor may give you a new access while the old one heals. Or, instead of peritoneal dialysis, you may start using hemodialysis, which uses a machine instead of the lining of the belly to filter waste from the blood^[21].

Preventing peritonitis

If you get peritoneal dialysis, you can help prevent peritonitis with good hygiene before, during and after dialysis. For example, it’s important to wash your hands and clean the skin around your catheter^[1].

Take these steps to help prevent peritonitis if you use peritoneal dialysis^[21]:

• Keep your access clean and dry. Check it every day for signs of infection, such as increased pain, swelling, warmth, or redness; red streaks leading from the access site; or pus draining from the access site
• Keep the end of your catheter covered when it is not in use
• Always wash your hands with soap and water before you touch your catheter
• Avoid swimming and bathing unless your dialysis team has told you it is okay. Always clean and dry your catheter and access right away after you get wet
• Follow your doctor’s instructions for showering

Prognosis and survival rates

Prognosis is guarded for patients with peritonitis. Reported survival rates are highly variable and depend on the cause, presence of infection, and development of systemic inflammatory response syndrome and organ dysfunction^[4].

Mortality rates associated with peritonitis were around 90% in the early 1900s. These rates have since come down to approximately 30% with the use of appropriate drug therapies and supportive care. Since 1926, mortality in peritonitis has decreased to an average of 30-40% with the development of new operative techniques, the introduction of antibiotics, and intensive care treatment^[12][13].

The mortality rate correlates with the severity of disease, which is usually assessed by scoring systems. Mortality also depends on early control of the septic source and whether the patient develops complications such as sepsis or multiple organ failure^[13].

Follow-up care is a key part of your treatment and safety. Be sure to make and go to all appointments, and call your doctor if you are having problems^[21].