Peritonitis

Overview

Peritonitis is a serious condition where the peritoneum — the thin layer of tissue that lines the inside of your belly and covers most of your abdominal organs — becomes inflamed. This is usually caused by an infection and needs urgent medical care.

Peritonitis is not very common, but it is very serious. It can happen to anyone, especially when another abdominal condition is present.

Peritonitis can affect people of any age. You are more likely to get it if you have liver disease with fluid in the belly, if you receive peritoneal dialysis for kidney problems, or if you have a condition that can cause a burst organ, such as a stomach ulcer or appendix.

Symptoms

Common symptoms

• Severe belly pain that gets worse when you move or press on your belly
• Belly that feels hard or swollen
• Fever and chills
• Nausea or vomiting
• Loss of appetite
• Fast heartbeat

Symptoms in children

• In children, the same signs may appear, but they may also be very irritable, unable to settle, or have a poor appetite. Younger children might cry or arch their back in pain.

Symptoms in older adults

• Older adults sometimes have less obvious pain. They may just feel generally unwell, confused, or develop a bloated belly with poor appetite.

Causes

Main causes

• The most common cause is a bacterial infection, often from a burst appendix, stomach ulcer, or an inflamed bowel.
• In people who get peritoneal dialysis, the dialysis tubing or fluid can become infected and cause peritonitis.
• Less often, an injury or a medical procedure can tear the belly lining and let bacteria in.
• In people with liver disease, a build-up of belly fluid (ascites) can become infected.

Risk factors

• Peritoneal dialysis for kidney failure
• Liver disease, especially with ascites (fluid in the belly)
• A weakened immune system
• Abdominal surgery or injury in the past
• Conditions like appendicitis, diverticulitis, or a stomach ulcer that can burst

When to see a doctor

See a doctor urgently if:

• See a doctor the same day if you have belly pain that is getting worse, is localised to one area, or comes with a fever. Peritonitis can develop quickly, so do not wait.
• Go to an emergency department if your pain is severe, you have a fever, or your belly feels hard.
• Call your local emergency number right away if you have any of the emergency symptoms listed above.

Book a routine appointment if:

• If you have mild belly discomfort that does not go away after a few hours, or if it happens with a change in your bowel habits, contact your doctor for advice. It is always better to mention it than to wait until it becomes severe.

Diagnosis

Doctors usually diagnose peritonitis by asking about your symptoms, examining your belly, and doing tests. Because peritonitis can get worse quickly, tests are often done in a hospital.

Tests that may be done

• Blood tests to check for infection and inflammation
• Imaging scans, such as a CT scan or ultrasound, to look inside your belly
• A sample of fluid from your belly, called a paracentesis, if there is excess fluid
• Sometimes a small telescope test, called laparoscopy, is used to look directly at the peritoneum

What to expect at your appointment

If your doctor suspects peritonitis, you will likely be admitted to hospital right away. Hospital doctors may run several tests. You may be given fluids through a drip and medicines to ease pain while they find the cause. This can feel uncomfortable, but the staff will keep you as comfortable as possible.

Treatment

Treatment for peritonitis usually starts in hospital. You will be given strong antibiotics through a drip, along with fluids and medicines to control pain and fever. If the cause is a burst organ or infected tissue, surgery may be needed. The exact treatment depends on what is causing the inflammation.

Self-care at home

• Rest as much as possible during treatment and recovery.
• Follow your doctor’s advice on wound care if you have had surgery.
• Take any medicines your doctor prescribes exactly as told — even if you start to feel better.
• Do not lift heavy objects or do strenuous activity until your doctor says it is safe.

Medical treatments

Medical treatment for peritonitis always begins with stabilising you in hospital. This may include IV (drip) fluids to keep you hydrated, antibiotics to fight infection, and pain relief. In many cases, surgery is needed to remove the source of the infection, such as a burst appendix, or to drain any pus that has collected.

When is surgery considered?

Surgery is often needed if peritonitis is caused by a burst appendix, stomach ulcer, or an abdominal injury. The surgeon will make small or large cuts in the belly to find and fix the problem and clean the infected area.

Living with this condition

Recovery from peritonitis takes time. You may feel tired and weak for several weeks. You will need to attend follow-up appointments and may need to rest at home before returning to work or school. Ask your healthcare team what to expect during your recovery.

Lifestyle tips

• Get plenty of rest and listen to your body.
• Build up your activity gradually, starting with short walks.
• Avoid alcohol and smoking while you recover, if possible.
• Keep all follow-up appointments so your recovery is properly monitored.

Diet and exercise

Start with light foods that are easy to digest, like soups and plain crackers, and drink plenty of fluids unless your doctor says otherwise. As you feel better, you can slowly return to your normal diet. Gentle walking can help your circulation and recovery, but avoid heavy exercise until your doctor confirms it is safe.

Mental health and emotional wellbeing

Going through a serious illness like peritonitis can be stressful and upsetting. You may feel anxious or low during and after treatment. These feelings are common. Talk to your healthcare team if you are struggling — they can offer advice and support. You can also contact local mental health services if you need someone to talk to.

Prevention

Not all cases of peritonitis can be prevented, because it often happens suddenly due to an underlying condition. But getting prompt treatment for conditions like appendicitis or a stomach ulcer can help prevent it from developing.

Complications

If left untreated

• Sepsis, a life-threatening reaction to infection that can spread through the body
• A collection of pus inside the belly, called an abscess
• Bowel blockage or damage to the internal organs
• Organ failure, including kidney or lung failure
• In severe cases, death

Long-term outlook

With prompt treatment, most people with peritonitis recover fully. The outlook depends on the cause, how quickly treatment is started, and your general health. While it is a serious condition, modern medicine is very good at treating it — especially when it is caught early.

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