Peritonitis is inflammation of the peritoneum, the thin layer of tissue that lines the inside of the abdomen and surrounds and supports organs, such as the stomach and liver.
It's caused by a bacterial or fungal infection. An infection of the peritoneum can rapidly spread into the blood and then on to the body’s organs.
Symptoms of peritonitis often come on quickly and include:
- severe abdominal pain
- a high temperature (fever) of 38C (100.4F) or above
- chills
Due to a high risk of serious complications developing, peritonitis is regarded as a medical emergency and requires immediate treatment.
When to get medical help
Sudden abdominal pain that gradually gets worse is usually a sign of a potentially serious infection or illness.
If you have this type of pain, contact your GP immediately. If this is not possible, call NHS Direct on 0845 4647 or your local out-of-hours service.
Causes of peritonitis
The most common cause of peritonitis is an infection that develops directly inside the peritoneum. Doctors refer to this as primary peritonitis.
The two major risk factors for primary peritonitis are:
It is estimated that 20% of people with cirrhosis who have a build-up of fluid inside their abdomen will also develop peritonitis at some point.
Following advancements in treatment, peritonitis associated with dialysis is less common than it used to be. It's estimated that most people being treated with peritoneal dialysis will experience one episode of peritonitis every two years.
A less common cause of peritonitis is an infection or injury in another part of the body that causes bacteria or fungi to infect the peritoneum. Doctors refer to this as secondary peritonitis.
If part of the digestive system breaks open as a result of an injury or an infection, for example when the appendix bursts due to appendicitis, bacteria can be released inside the peritoneum.
Treatment for peritonitis
Peritonitis is a serious condition that needs to be diagnosed and treated quickly to prevent possibly fatal complications developing. Therefore, it's regarded as a medical emergency and treatment for peritonitis will usually involve being admitted to hospital.
The underlying infection will be treated with injections of antibiotics or antifungal medication, depending on the cause of the infection. In some cases, surgery may be required to repair damage to the peritoneum or to treat the underlying cause of the infection.
However, due to the often aggressive nature of peritonitis, death can occur despite the best efforts of medical staff.
Outlook
The outlook for peritonitis varies widely depending on its cause. Peritonitis associated with cirrhosis has the worst outlook, with the risk of death being as high as 50%, whereas it’s estimated that 10% of people will die from secondary peritonitis.
