Spontaneous bacterial empyema is a serious infection of the fluid in your pleural cavity that can happen when you have a fluid buildup around your lungs called hepatic hydrothorax.

Spontaneous bacterial empyema is an infection of the fluid in your pleural cavity when you already have hepatic hydrothorax. Your pleural cavity is the space between the visceral pleura (the very thin membrane around your lungs) and the parietal pleura (the thicker sac around your lungs). “Spontaneous” means it comes on suddenly.

Hepatic hydrothorax is a complication of chronic liver disease involving the buildup of fluid in the space outside of your lungs.

Spontaneous bacterial empyema can be life threatening and requires treatment with antibiotics. In some cases, the excess fluid around your lungs may need to be drained with a chest tube.

Here, we examine this complication of liver disease in more detail, including what causes it, who’s at risk, and the symptoms it causes.

Your liver carries out more than 500 functions. Damage to your liver can cause many serious health problems.

Spontaneous bacterial empyema is a complication of hepatic hydrothorax, which itself is a complication of cirrhosis.

Cirrhosis is scarring of your liver caused by long-term damage. The most common cause is drinking too much alcohol for many years.

How cirrhosis causes spontaneous bacterial empyema

Cirrhosis can lead to a condition called portal hypertension, where the blood pressure in the veins leading to your liver becomes high. This increased pressure leads to the widening of these blood vessels and the release of substances that harm kidney function.

Reduced kidney function can lead to ascites and hepatic hydrothorax. Ascites refers to fluid buildup in your abdomen, and hepatic hydrothorax is fluid buildup in your pleural space due to liver disease.

Most people with hepatic hydrothorax have significant ascites. However, hepatic hydrothorax can also develop without fluid buildup in your abdomen.

Spontaneous bacterial empyema occurs when a bacterial infection develops in the excess fluid around the lungs of a person with hepatic hydrothorax. Some researchers have suggested that spontaneous bacterial empyema might develop due to ruptured blisters between the abdominal and pleural cavities, which may cause bacteria-containing fluid to enter the space around the lungs.

People with spontaneous bacterial empyema may develop signs and symptoms like:

People with spontaneous bacterial empyema also usually have ascites, which can cause a swollen and tender belly.

They also commonly have another condition called spontaneous bacterial peritonitis. This is an infection of fluid buildup in the abdomen in a person with ascites.

Spontaneous bacterial empyema is a complication of hepatic hydrothorax. It’s thought to develop in about 10–16% of people with hepatic hydrothorax. Hepatic hydrothorax has been reported in about 5–16% of people with cirrhosis and portal hypertension.

Roughly 1 in 400 adults in the United States are living with cirrhosis.

Spontaneous bacterial empyema can be life threatening. In a 2022 review, researchers reported rates of dying from 20–38%. Some studies have reported mortality rates as high as 45%.

Doctors will start the diagnostic process for spontaneous bacterial empyema by:

  • doing a physical exam
  • reviewing your medical history
  • assessing your symptoms

If your doctor suspects spontaneous bacterial empyema, they will likely order a test called thoracentesis. Thoracentesis involves obtaining a sample of fluid from your pleural cavity to check for bacteria. Your doctor will take the sample by inserting a needle between your ribs into your pleural space.

You may receive additional tests like ultrasound or CT scans if your doctor finds signs of bacteria.

There are no standard treatment guidelines for spontaneous bacterial empyema since it’s still relatively understudied. The main treatment is antibiotics to kill the bacteria in your pleural space.

Mild spontaneous bacterial empyema is usually treated with antibiotics called third-generation cephalosporins. For harder-to-treat cases, you may also need the fluid around your lungs drained. This may involve a chest tube that remains attached to your lung for several weeks.

However, this procedure can be dangerous in people with hepatic hydrothorax, with mortality rates around 30%. The chances of serious complications seem to increase the longer the chest tube is attached.

A type of surgery called thoracoscopic debridement may be needed to remove dead or infected tissue in some cases. This procedure can be performed through a large incision or with small incisions and a thin tube with a video camera.

Preventing spontaneous bacterial empyema starts with taking steps to avoid cirrhosis of the liver. Ways you can prevent cirrhosis include:

  • limiting alcohol consumption
  • taking steps to avoid hepatitis B and C, such as:
    • using protection when having sex with new partners or those with hepatitis B and C
    • avoiding sharing injection equipment
  • maintaining a healthy weight

It’s important to get prompt medical attention if you develop symptoms of late-stage liver disease, such as:

Medical emergency

Spontaneous bacterial empyema can be life-threatening. Call emergency medical services or go to the nearest emergency room if you have chronic liver disease and develop:

  • trouble breathing
  • fever
  • rapid heart rate

Here are some frequently asked questions people have about spontaneous bacterial empyema.

Which bacteria cause spontaneous bacterial empyema?

In a 2022 review, the most common bacteria identified in people with spontaneous bacterial empyema were

  • Escherichia coli
  • Klebsiella pneumonia
  • Pseudomonas aeruginosa
  • Enterococcus

What is the difference between pleural infection and empyema?

A pleural infection is the bacterial invasion of the lining between your lung and chest cavity. The most common cause of pleural infection is pneumonia. Empyema is an infection of the fluid in your pleural cavity. It can develop as a complication of pneumonia.

Spontaneous bacterial empyema is potentially life threatening and requires treatment with antibiotics. It’s important to get immediate medical attention if you have liver disease and symptoms like fever or problems breathing.