Spontaneous bacterial peritonitis: symptoms, causes and treatment

The peritoneum is the thin lining of the tummy that covers organs including the liver, kidneys and bowel. When it becomes infected the condition is called peritonitis. The NHS says that if the lining becomes infected, the internal organs it covers can also be damaged.

Most peritonitis follows a clear event, such as a burst appendix or stomach ulcer. Spontaneous bacterial peritonitis is different: it affects people who already have fluid in the tummy, usually because of cirrhosis, and the infection arises without such an obvious source. Its name reflects that no perforation or surgical cause is found.

Specific UK patient leaflets on SBP are scarce, so this guide draws on NHS information on peritonitis and cirrhosis and on Liver UK's cirrhosis guidance. Your liver team will explain how these general points apply to you.

Cirrhosis is permanent scarring of the liver. Liver UK describes it as a later stage in many types of liver disease and explains that people with compensated cirrhosis may feel well, while decompensated cirrhosis means the body is no longer coping and complications develop that often need urgent treatment.

The NHS lists a swollen tummy, legs, ankles or feet among the symptoms of worsening cirrhosis and names ascites, fluid building up in the tummy, as a complication. It also lists infections, such as urinary tract infections and pneumonia, and sepsis among the complications of cirrhosis. SBP belongs to this family of infections: fluid that has collected in the tummy can become infected.

Liver UK notes that triggers such as infections or alcohol intake can push cirrhosis from compensated to decompensated, and that this is hard to predict. Treating the cause of liver damage or the trigger can sometimes reverse decompensation.

The NHS lists the symptoms of peritonitis as tummy pain, a very high temperature or feeling hot, cold or shivery, a rapid heartbeat, and not being able to pee or peeing much less than normal. There may also be a lack of appetite, feeling or being sick, and a swollen tummy.

In someone with cirrhosis, a swollen tummy is already a recognised problem, so the key is a change: new or worse tummy pain, a fever, feeling suddenly more unwell or more confused. The NHS advises people diagnosed with cirrhosis to seek urgent advice from a GP or NHS 111 if they have a swollen tummy, legs, ankles or feet, yellowing of the skin or eyes, or are more breathless than usual.

• Tummy pain, or a tummy that is becoming more swollen or tender.

• A high temperature, shivering, feeling hot or cold.

• A fast heartbeat, or passing much less urine than usual.

• Feeling or being sick, or loss of appetite.

• Sudden confusion or slurred speech: the NHS says to call 999 or go to A&E for this in someone with cirrhosis.

The NHS states that if peritonitis is diagnosed you will need treatment in hospital to get rid of the infection, and that this usually involves antibiotics given into a vein. If you cannot eat, a feeding tube or liquid nutrients given into a vein may be used, and surgery is sometimes needed to treat a cause or drain an abscess.

In people with cirrhosis, the hospital team will also be looking after the liver, the fluid and the kidneys at the same time. The pages read for this guide do not describe the detailed hospital protocol for SBP, so those specifics are best discussed with your hepatology or gastroenterology team.

Following an episode, teams often review how to prevent a recurrence and how to manage the underlying liver disease. Liver UK says that treatment focuses on treating the cause of damage, helping with symptoms and managing complications, and that the only cure for cirrhosis is a liver transplant, which not everyone will need or be able to have.

SBP is a serious complication. The NHS describes peritonitis as potentially life threatening if untreated, and cirrhosis complications such as infection and sepsis as potentially serious. With prompt hospital treatment many people recover from an episode, but it can signal that the liver disease is advanced, so it is a reason to review the overall plan with a liver specialist.

Day to day, the practical steps are the ones Liver UK and the NHS describe for cirrhosis: treat the underlying cause, avoid alcohol if advised, attend follow-up, and know which symptoms need urgent help. Having a swollen tummy or confusion is not something to wait out.

Suspected SBP is an emergency that is assessed through A&E or an acute medical unit on the NHS, because it needs hospital admission and intravenous treatment. Private hepatology appointments can help with planning long-term liver care, but they are not a substitute for urgent hospital assessment when symptoms change suddenly.