Liver Abscess

What is Liver Abscess?

A liver abscess is simply a mass filled with pus in the liver, often caused by liver injury or a stomach infection that gets spread through the bloodstream flowing to the liver. These abscesses are typically classified as either pyogenic (caused by bacteria) or amoebic (caused by a parasite), with a few instances caused by other parasites and fungi. The most common parasite responsible for amoebic infections is Entamoeba histolytica. Bacteria involved in pyogenic abscesses often include E.coli, Klebsiella, Streptococcus, Staphylococcus, and types that don’t need air to survive (anaerobes). These abscesses don’t occur frequently, but it’s important to understand their severity due to the high risk of death in patients if they’re left untreated.

Usually, liver abscesses form when there’s a leak from the bowel in the stomach area that travels to the liver through a blood vessel called the portal vein. In many instances, infections in the bile duct (a tube that carries bile from the liver to the small intestine) can directly lead to a liver abscess.

Liver abscesses can be categorized based on their location in the liver or the source of the infection. About half of solitary (or single) liver abscesses occur in the right lobe, the bigger part of the liver with more blood supply, rather than in the left or caudate lobes. Based on the source, if the cause is infectious, liver abscesses are mostly categorized as either bacterial (including amoebic) or originating from parasites (including those from hydatiform cysts).

What Causes Liver Abscess?

In the past, a common reason people developed a liver abscess, which is a filled pocket in the liver, was due to appendicitis. However, with better diagnosis and treatment available now, this has dropped to under 10%. Currently, problems with the biliary tract, which is involved in producing and transporting bile, are the main causes of pus-filled liver abscesses. These problems include things like gallstones, scarring, cancer, and birth defects.

Half of all bacteria-related cases still occur due to cholangitis, inflammation of the bile duct. Other less common causes can include bacterial infection of the liver’s main blood vessels, inflammation of the pockets located in your digestive system (diverticulitis), inflammation of the gallbladder, or injuries.

Occasionally, abscesses may seemingly come from nowhere (cryptogenic origin). The organisms most often found in abscesses include E.coli, Klebsiella, Streptococcus, Staphylococcus, and various anaerobic organisms, meaning they thrive without oxygen. If Streptococcus or Staphylococcus are found alone, doctors usually look for another source of infection that may have spread to the liver via the bloodstream.

In Southeast Asia, Klebsiella pneumoniae is often the cause of liver abscesses and is thought to be related to colorectal cancer. This type of bacteria usually exists in people without liver or bile duct diseases, spreads rapidly, and might lead to a severe form of liver abscess. This is especially true for people with diabetes.

If the source is a type of organism that can live without oxygen (anaerobe), it’s usually a parasite called Entamoeba histolytica. This parasite can affect the liver, initially causing an inflammation of the colon, traveling through the bloodstream to the liver, and causing a liver abscess. Even though this is rare in the United States, it can still be found in people who have recently moved to the US or travelers coming from other countries.

Another rare but important organism is Echinococcus granulosus, which can cause a fluid-filled sac in the liver called a hydatid cyst. This is caused by the larval stage of the Echinococcus tapeworm, which comes from the Taeniidae family. Patients who have this often experience stomach pain, diarrhea, and enlarged liver. Hydatid cysts come from dogs and can take a long time to cause symptoms in humans. In most cases, these cysts are found late and usually by accident.

Risk Factors and Frequency for Liver Abscess

Every year, around 2.3 people in every 100,000 encounter a liver abscess, with men tending to be more affected than women. It’s important to note that your age can dictate the type of liver abscess you develop; those who are 40 to 60 years old are more prone to develop liver abscesses not derived from injuries.

On a yearly basis, there are about 2.3 cases of liver abscess per 100,000 people.
Men are more likely to develop liver abscess than women.
People aged 40-60 years are most at risk for non-trauma related liver abscesses.
A large number of liver abscesses are known as pyogenic, meaning they are caused by bacteria.
In a study of 67 patients with liver abscesses in the Middle East, 56 cases were due to bacterial causes, mostly from a type of bacteria named Klebsiella pneumonia. Majority of these patients were males.
In Taiwan, the incidence is quite high, at 17.6 cases per 100,000 people.
Overall, pyogenic liver abscesses make up about half of all organ-based abscesses and 13% of those located within the abdominal area.

Signs and Symptoms of Liver Abscess

Before moving to any diagnostic measures, it’s crucial to get a comprehensive understanding of the patient’s personal and medical background. This includes their job, travel history, place of birth, and any recent infections or treatments they might have had. Certain factors can increase the risk of developing liver abscesses, such as having diabetes, cirrhosis, being an older male, having a weakened immune system or using proton pump inhibitors.

Once this information has been gathered, reviewing the patient’s symptoms and performing a physical examination can provide more insight. Symptoms could include:

Fever
Chills
Night sweats
Feeling unwell
Nausea or vomiting
Right shoulder pain (caused by irritation of the phrenic nerve)
Pain in the right upper part of the abdomen
Cough
Shortness of breath
Loss of appetite
Unexplained weight loss
Dark urine

Physical examination may reveal that the liver is enlarged, and the patient might also exhibit signs of jaundice. Although right upper abdominal pain, jaundice, and fever (referred to as Charcot’s triad) is a symptom of cholangitis, liver abscess should also be taken into consideration. In rare cases, patients may present severe symptoms such as shock which could be due to septic shock or anaphylactic shock if a type of tumor known as a hydatid cyst ruptures.

In cases of liver abscesses caused by Klebsiella bacteria, there may be symptoms related to the eyes, brain, and meninges due to the spreading of infection. These symptoms may persist even after the liver abscess has been drained.

For Echinococcus infection, an asymptomatic phase may occur in children. Years later, symptoms may appear due to the reactivation of the infection. These symptoms are linked to the type, size, and location of the cysts inside the body. Small cysts in non-critical organs might not be detected, but large ones in critical areas can cause symptoms due to compression or rupture. Generally, these cysts grow at a rate of 1 to 5 centimeters a year. In two-thirds of Echinococcus infection cases, the liver is affected. Symptoms typically appear when the diameter of the cyst is 10 cm and may include biliary colic, cholangitis, obstructive jaundice, portal and venous obstruction, and bronchial fistula. If a cyst ruptures, the patient may experience severe peritonitis or anaphylaxis.

Testing for Liver Abscess

If your doctor suspects that you may have a liver abscess—an accumulation of pus in the liver—he or she will order several tests to confirm the diagnosis. The first step involves a blood test that checks your white blood cell count to see if there is any infection. This includes tests for substances called liver enzymes, which are generally elevated when there is liver damage, as well as proteins your liver produces, and other blood markers that indicate inflammation or infection.

In some cases, particularly for people who have recently traveled or reside in places like Southeast Asia or Africa, an amebic liver abscess might be suspected. This type of abscess is caused by a parasite called Entamoeba histolytica. If your doctor suspects this, they will require a stool test or a blood test specifically for this parasite. Another type of liver issue caused by a parasite is a hydatid cyst, which is typically caused by a worm called Echinococcus. For this, another blood test called an ELISA will be taken. If the ELISA is positive, further confirmatory tests will be performed. However, the results may depend on many factors including the size and location of the cysts.

After these blood tests, your doctor will also likely order some imaging tests. The initial imaging test is typically an abdominal ultrasound. This non-invasive procedure can reveal the presence of any abnormal areas in the liver. If any abnormal areas are seen on the ultrasound, a CT scan—the next step—might offer a clearer image. The CT scan can be more specific in identifying infection characteristics.

Another test that can help with your diagnosis is a needle aspiration, conducted under the guidance of ultrasound or CT scan. Your doctor uses a needle to collect a small sample of fluid or tissue from your liver for further examination. This can help in identifying the exact cause of your liver problem.

Based on these imaging and laboratory tests, your doctor can then confirm a diagnosis of a liver abscess if there are discovered cystic or solid areas in the liver. It’s crucial to start treatment as soon as possible after this diagnosis due to the high risk of complications if the condition is left untreated.

Treatment Options for Liver Abscess

The central treatments for abscesses include draining the abscess and usage of antibiotics. Here’s how it works;

First, the abscess needs to be emptied. This can be done using ultrasound or CT scans as a guidance. If the abscess is smaller than 5 cm, this might just involve using a needle to aspirate (draw out) the contents, sometimes more than once. For larger abscesses, they may need to put in a tube to drain it. This method can be very effective for abscesses larger than 5 cm. Alternatively, they can also use a procedure known as laparoscopic drainage.

In some cases, surgery might be needed to treat the abscess. This is typically the case if the abscess is causing peritonitis (inflammation of the abdominal lining), if it has ruptured or if previous drainage procedures haven’t worked. The surgeon can either approach the abscess through the abdomen or via the back of the chest; the best approach depends on the abscess’s location.

Importantly, they’ll also need to identify and treat the cause of the abscess. For example, if the abscess is a complication of a procedure on your liver, they might drain the abscess using a procedure called endoscopic retrograde cholangiopancreatography (ERCP).

While treating the abscess, you’ll also be given antibiotics to help get rid of the infection. At first, doctors often use a combination of antibiotics to cover a wide range of possible infectious organisms. Once the results of your cultures (tests to identify the organisms causing the infection) are known, the doctors can adjust the antibiotics so they’re specifically targeting the responsible organisms. However, some organisms are hard to culture, so you may need to take these combination antibiotics for the whole course of treatment, just to be safe.

In some instances, such as when the patient is too sick for drainage, the abscess may be treated with antibiotics alone. However, this is typically seen as a less desirable approach.

If the abscess has been caused by a tapeworm infection, doctors will treat you with an antiparasitic drug like albendazole. This treatment can last for several years. Severe or complicated cases may also require drainage. The surgeons have to be very careful when draining these cysts to prevent them from rupturing, which can cause the patient to suddenly become critically unwell.

In one particular study, the average hospital stay for patients with a pyogenic (pus-forming) liver abscess was approximately 13.6 days, and these patients typically needed antibiotics for about 34.7 days. Conversely, patients with amebic liver abscesses (caused by a parasite called Entamoeba histolytica) usually spent about 7.7 days in the hospital and were treated for around 11.8 days.

A liver abscess can cause upper right-side abdominal pain, fever, and inflammation of the liver. However, these symptoms are also common in several other conditions related to the liver and other illnesses, which makes diagnosis challenging. The following conditions are often considered:

Viral inflammation of the liver
Gallbladder inflammation
Inflammation of the bile duct
Pneumonia in the right lower lung lobe
Appendicitis
Decaying liver masses

Additionally, other factors that may cause inflammation of the liver, such as an autoimmune response, drug-induced reactions, and excessive use of pain relievers like acetaminophen, can also mimic the symptoms of liver abscess. However, these are generally not associated with pain.

What to expect with Liver Abscess

Improvements in technology and the use of specific antibiotics have significantly improved the outlook for patients with liver abscesses. Now, only between 2.5% and 19% of patients with liver abscesses in hospital care die from the condition. However, certain factors can still raise this risk. Elderly people, those admitted to intensive care units (ICUs), and patients who have shock, cancer, fungal infections, cirrhosis (liver disease), chronic kidney failure, acute respiratory failure, severe illness, or a bile-related form of the abscess are more likely to die from it. Additionally, liver abscesses often come back in patients with bile tract diseases.

Hydatic cysts, a particular type of liver condition, generally have a positive outlook. More than half (57%) of these cysts remain stable and typically do not cause any symptoms, even if they get bigger. About 15% of patients with hydatic cysts need surgery, often years after the diagnosis. Remarkably, 76% of patients who do not have surgery stay symptom-free for years.

Possible Complications When Diagnosed with Liver Abscess

If liver abscesses are not treated in good time, they can burst, leading to conditions like peritonitis and shock. In some cases, the area around the rupture walls off, which may lead to chronic pain and discomfort in the upper right area of the stomach along with the occasional fever at night. Even after the abscess is drained, it is possible for complications such as liver or kidney failure, infections, internal abdominal injuries, or recurrent liver abscesses to occur.

Other complications that may arise are:

Subphrenic abscess (an abscess under the diaphragm)
Fistula formation to nearby organs (like pleuropulmonary and hypobranchial fistula)
Acute pancreatitis
Blood clot formation in the abdominal or liver veins
Liver pseudoaneurysm, a false aneurysm in the liver
Endophthalmitis (infection inside the eye)
Central nervous system septic emboli (blood clots carrying bacteria through the central nervous system)

It is crucial to follow up with patients after they have received treatment to prevent and identify these complications. The best way to prevent liver abscesses is to treat intraabdominal infections right away. Taking antibiotics for 4 to 6 weeks after the abscess has been drained can prevent almost all complications. Administering antibiotics during chemoembolization or endoscopic retrograde cholangiography can also help prevent future abscess formation.

The changes seen on imaging tests will take longer to disappear than the clinical symptoms or lab abnormalities, which is quite common with many medical conditions. Enough time should be given to these changes before expecting the images to return to normal.

Recovery from Liver Abscess

After surgery, doctors typically continue with antibiotic treatment to prevent possible issues. They also keep an eye on the patient’s health indicators like blood count, kidney function, and bilirubin and aminotransferase levels. These checks help determine how well the patient’s organs are working and how much damage an illness or treatment might have caused.

Preventing Liver Abscess

To stay safe from hydatid cysts, which are caused by a type of parasite called Echinococcus, people should avoid coming into contact with animal droppings or saliva. Doctors can teach people how to take basic safety steps to lower the chance of getting a liver abscess, a painful infection in the liver. While most instances of liver abscess are not fatal, in some cases, if complications occur, they can lead to a high risk of death. Therefore, it’s important to take precautions.

Frequently asked questions

A liver abscess is a mass filled with pus in the liver, often caused by liver injury or a stomach infection that spreads through the bloodstream to the liver. It can be classified as either pyogenic (caused by bacteria) or amoebic (caused by a parasite), with some cases caused by other parasites and fungi.

On a yearly basis, there are about 2.3 cases of liver abscess per 100,000 people.

Signs and symptoms of liver abscess can vary, but some common ones include: - Fever - Chills - Night sweats - Feeling unwell - Nausea or vomiting - Right shoulder pain (caused by irritation of the phrenic nerve) - Pain in the right upper part of the abdomen - Cough - Shortness of breath - Loss of appetite - Unexplained weight loss - Dark urine In addition to these symptoms, a physical examination may reveal an enlarged liver and signs of jaundice. It's important to note that while right upper abdominal pain, jaundice, and fever (known as Charcot's triad) can be a symptom of cholangitis, liver abscess should also be considered. In rare cases, severe symptoms such as shock may occur, which could be due to septic shock or anaphylactic shock if a hydatid cyst ruptures. In cases of liver abscesses caused by Klebsiella bacteria, symptoms related to the eyes, brain, and meninges may occur due to the spread of infection. These symptoms may persist even after the liver abscess has been drained. For Echinococcus infection, symptoms may appear years later and are linked to the type, size, and location of the cysts inside the body. Symptoms can include biliary colic, cholangitis, obstructive jaundice, portal and venous obstruction, and bronchial fistula. If a cyst ruptures, severe peritonitis or anaphylaxis may occur.

Liver abscess can be caused by various factors, including problems with the biliary tract (such as gallstones, scarring, cancer, and birth defects), bacterial infections (such as cholangitis or infections of the liver's main blood vessels), inflammation of the pockets in the digestive system (diverticulitis), inflammation of the gallbladder, injuries, and sometimes from unknown sources (cryptogenic origin). Certain bacteria, parasites, and organisms like E.coli, Klebsiella, Streptococcus, Staphylococcus, anaerobic organisms, Entamoeba histolytica, and Echinococcus granulosus can also cause liver abscess.

The doctor needs to rule out the following conditions when diagnosing Liver Abscess: - Viral inflammation of the liver - Gallbladder inflammation - Inflammation of the bile duct - Pneumonia in the right lower lung lobe - Appendicitis - Decaying liver masses - Autoimmune response - Drug-induced reactions - Excessive use of pain relievers like acetaminophen

The types of tests that are needed for diagnosing a liver abscess include: - Blood tests: These tests check for white blood cell count, liver enzymes, proteins produced by the liver, and other blood markers that indicate inflammation or infection. - Stool test or blood test for specific parasites: If an amebic liver abscess or a hydatid cyst is suspected, a stool test or blood test specifically for the parasites Entamoeba histolytica or Echinococcus will be ordered. - Imaging tests: An abdominal ultrasound is typically the initial imaging test, followed by a CT scan if any abnormal areas are seen on the ultrasound. These tests can reveal the presence of abnormal areas and help identify infection characteristics. - Needle aspiration: This test involves using a needle to collect a small sample of fluid or tissue from the liver for further examination, which can help identify the exact cause of the liver problem.

Liver abscesses can be treated through draining the abscess and using antibiotics. The abscess can be emptied using ultrasound or CT scans as a guidance. For smaller abscesses, a needle can be used to aspirate the contents, while larger abscesses may require a tube to drain it or laparoscopic drainage. In some cases, surgery may be needed if the abscess is causing peritonitis, has ruptured, or previous drainage procedures haven't worked. The cause of the abscess also needs to be identified and treated. Antibiotics are given to help get rid of the infection, and the specific antibiotics used can be adjusted based on the results of cultures. In cases caused by tapeworm infection, antiparasitic drugs like albendazole are used. The average hospital stay for patients with a pyogenic liver abscess is approximately 13.6 days, while patients with amebic liver abscesses typically spend about 7.7 days in the hospital.

When treating liver abscess, there can be several side effects and complications. These include: - Peritonitis (inflammation of the abdominal lining) - Rupture of the abscess - Chronic pain and discomfort in the upper right area of the stomach - Fever at night - Liver or kidney failure - Infections - Internal abdominal injuries - Recurrent liver abscesses - Subphrenic abscess (an abscess under the diaphragm) - Fistula formation to nearby organs - Acute pancreatitis - Blood clot formation in the abdominal or liver veins - Liver pseudoaneurysm (a false aneurysm in the liver) - Endophthalmitis (infection inside the eye) - Central nervous system septic emboli (blood clots carrying bacteria through the central nervous system) It is important to follow up with patients after treatment to prevent and identify these complications. Taking antibiotics for 4 to 6 weeks after the abscess has been drained can help prevent most complications.

The prognosis for liver abscess has significantly improved due to advancements in technology and the use of specific antibiotics. Currently, only between 2.5% and 19% of patients with liver abscesses in hospital care die from the condition. However, certain factors such as age, admission to intensive care units, presence of shock, cancer, fungal infections, cirrhosis, chronic kidney failure, acute respiratory failure, severe illness, or a bile-related form of the abscess can increase the risk of death. Additionally, liver abscesses often recur in patients with bile tract diseases.

You should see a gastroenterologist or a hepatologist for liver abscess.