Understanding Peritonitis: A Complete Patient Guide

Peritonitis is inflammation of the peritoneum, the thin tissue that lines the inside of the abdomen and covers many abdominal organs. It is often caused by infection or a leak from an organ and usually requires prompt medical evaluation and treatment.

Overview: what peritonitis means

Peritonitis is inflammation of the peritoneum, the delicate lining of the abdominal cavity. In most cases, this happens because bacteria or other germs enter the abdomen, or because fluid from the stomach, intestine, gallbladder, or another organ leaks into the abdominal space. This irritation and infection can spread quickly, so peritonitis is not something to monitor at home for long.

Patients often ask whether peritonitis is simply “stomach pain.” It is not. While abdominal pain is a major symptom, peritonitis affects the body more broadly and can lead to dehydration, infection in the bloodstream, and problems with vital organs if treatment is delayed. That is why doctors treat it as an urgent condition rather than a routine digestive complaint.

Peritonitis can be grouped in a few ways. Primary peritonitis develops without a hole in the bowel, often in people with liver disease and fluid in the abdomen. Secondary peritonitis is more common and happens when an organ problem such as appendicitis, a perforated ulcer, bowel injury, or a ruptured diverticulum allows infection or irritants to enter the abdominal cavity. A related form can occur in people receiving peritoneal dialysis.

Symptoms and how it may feel

The hallmark symptom of peritonitis is abdominal pain that is significant, persistent, and often worse with movement, coughing, or touch. Many people describe the abdomen as very tender, tight, or swollen. Some prefer to stay still because even small movements can increase discomfort.

Other symptoms can include fever, chills, nausea, vomiting, bloating, loss of appetite, constipation, or difficulty passing gas. As the condition worsens, a person may feel weak, thirsty, lightheaded, or confused. These can be signs that the infection is affecting the whole body.

People on peritoneal dialysis may notice somewhat different warning signs, such as cloudy dialysis fluid, abdominal discomfort during exchanges, fever, or redness around the catheter area. In any setting, symptoms can vary by age and overall health. Older adults, young children, and people with weakened immune systems may have less typical signs but can still become seriously ill.

• Sudden or worsening abdominal pain
• Abdominal tenderness or rigidity
• Fever or chills
• Nausea and vomiting
• Bloating or a swollen abdomen
• Reduced bowel movements or inability to pass gas
• Cloudy dialysis fluid in people on peritoneal dialysis

Causes and risk factors

Peritonitis usually starts when bacteria, digestive fluids, bile, blood, or chemical irritants enter the normally sterile abdominal cavity. A common cause is a hole or tear in the digestive tract. This may happen with a burst appendix, a perforated stomach ulcer, a bowel perforation, inflammatory bowel disease, trauma, or complications after abdominal surgery. Doctors may investigate the source carefully because treatment often depends on correcting the underlying problem.

Another important cause is infection of fluid already present in the abdomen, especially in people with advanced liver disease and ascites. This is called spontaneous bacterial peritonitis. It can occur without a visible hole in the intestine and is a known complication in cirrhosis. Patients who have significant ascites from liver disease may already be under care for conditions related to the liver or chronic liver damage, and any new fever, pain, or confusion should be assessed promptly.

Peritoneal dialysis also increases risk because the abdominal lining is used as a filter through a catheter. If germs enter during exchanges or through the catheter site, infection can develop. Additional risk factors for peritonitis include recent abdominal procedures, abdominal injury, weakened immunity, gastrointestinal perforation, severe infection elsewhere, and diseases that affect the bowel, such as diverticulitis or appendicitis.

How doctors diagnose peritonitis

Diagnosis begins with a careful medical history and physical examination. A doctor will ask when symptoms started, whether pain came on suddenly or gradually, and whether there is a history of ulcers, liver disease, dialysis, recent surgery, or abdominal injury. During the exam, marked tenderness, guarding, or a rigid abdomen can raise strong concern for peritonitis.

Blood tests often help show infection, inflammation, dehydration, or problems with kidney function and electrolytes. Imaging is also important. An abdominal X-ray may show free air if there is a perforation, while ultrasound or advanced imaging such as CT is often used to look for fluid, abscesses, organ inflammation, or a source of leakage. The exact imaging choice depends on the patient’s condition and what the care team suspects.

If there is fluid in the abdomen, doctors may remove a sample with a needle in a procedure called paracentesis. This fluid can be tested for white blood cells, bacteria, and other signs of infection. In people on peritoneal dialysis, the dialysis fluid itself is tested. Because the condition can worsen quickly, doctors often begin treatment as soon as peritonitis is strongly suspected, sometimes before all test results are back.

Treatment options and hospital care

Treatment for peritonitis usually starts in the hospital. The first goals are to control infection, support circulation, relieve symptoms, and treat the cause. Intravenous fluids are commonly given to help with dehydration and blood pressure, and antibiotics are started promptly when infection is suspected. Pain relief, nausea control, and close monitoring are also part of care.

If there is a perforation, a burst appendix, dead bowel, an abscess, or another problem that cannot heal on its own, surgery may be needed urgently. Depending on the cause, the care team may recommend appendix surgery, colon and rectum surgery, or other abdominal procedures to repair a tear, remove infected tissue, or drain pus. In some cases, image-guided drainage can be used for a localized abscess.

Patients with spontaneous bacterial peritonitis are usually treated with antibiotics and supportive care, along with management of the underlying liver disease and ascites. People on peritoneal dialysis may receive antibiotics through the dialysis fluid and may need temporary changes to dialysis treatment if infection is severe. In complex cases, a multidisciplinary team may be involved. Near the end of the care pathway, some international patients choose centers such as Acibadem International, where multidisciplinary specialists in JCI-accredited hospitals evaluate and treat abdominal infections and related surgical conditions.

Recovery, prevention, and self-care

Recovery depends on the cause, how quickly treatment begins, and the person’s overall health. Some people improve rapidly once antibiotics and source control are started, while others need longer hospital care. After discharge, recovery may involve wound care, rest, a gradual return to eating, follow-up blood tests, and management of the condition that caused the episode.

There is no single way to prevent all cases of peritonitis, but some steps can reduce risk. People on peritoneal dialysis should follow sterile technique carefully, keep the catheter area clean, and report cloudy fluid or abdominal pain right away. Those with cirrhosis and ascites should keep scheduled follow-ups and ask their doctor what warning signs require urgent review. Fast treatment for abdominal conditions such as ulcers, bowel disease, and an inflamed appendix can also help prevent complications.

Self-care at home should focus on recovery after medical treatment, not on treating suspected peritonitis without help. It is reasonable to rest, drink fluids if allowed, and follow discharge instructions, but severe abdominal pain, fever, vomiting, or a hard swollen abdomen should not be managed only with home remedies. Delays can increase the risk of complications such as sepsis or abscess formation.

When to seek medical care

Medical care should be sought urgently for sudden or severe abdominal pain, especially when it is paired with fever, vomiting, abdominal swelling, faintness, or tenderness that makes movement painful. Emergency assessment is also important if a person cannot pass stool or gas, feels unusually weak or confused, or has signs of dehydration.

People with liver disease and abdominal fluid should contact a doctor promptly for new abdominal pain, fever, worsening weakness, or confusion. Those on peritoneal dialysis should seek immediate advice for cloudy dialysis fluid, abdominal discomfort during exchanges, fever, or redness or discharge around the catheter site.

Prompt evaluation matters because peritonitis may progress quickly and can sometimes lead to sepsis. Early treatment gives doctors the best chance to control infection, identify the source, and prevent damage to the intestines and other organs.

Frequently asked questions

Is peritonitis an emergency?

Peritonitis is often a medical emergency because infection or leakage in the abdomen can spread quickly. A person with severe abdominal pain, fever, vomiting, or a rigid tender abdomen should be assessed urgently.

What causes peritonitis most often?

A common cause is a leak or perforation from an abdominal organ, such as a burst appendix, bowel injury, or perforated ulcer. It can also happen in people with cirrhosis and ascites or as a complication of peritoneal dialysis.

Can peritonitis go away on its own?

Peritonitis should not be expected to improve on its own. Because it can worsen quickly and lead to serious complications, it usually needs prompt medical treatment and sometimes surgery.

How is peritonitis different from ordinary stomach pain?

Ordinary stomach pain may come from indigestion, a virus, or constipation and often improves with time. Peritonitis usually causes more severe, persistent pain with tenderness, bloating, fever, or pain that worsens with movement.

How do doctors confirm peritonitis?

Doctors use a combination of symptoms, physical examination, blood tests, and imaging such as ultrasound or CT. If there is fluid in the abdomen, they may test it directly to look for infection.

Can peritonitis be treated without surgery?

Some cases can be treated with antibiotics, fluids, and careful monitoring, especially spontaneous bacterial peritonitis or certain dialysis-related infections. Surgery is usually needed when there is a perforation, dead tissue, an abscess, or another source that must be repaired or removed.

References

• National Institute of Diabetes and Digestive and Kidney Diseases
• MedlinePlus
• Merck Manual Professional Edition
• Centers for Disease Control and Prevention
• American College of Gastroenterology

This article is for general information only and is not a substitute for professional medical advice. Please consult a qualified doctor about your individual situation.