Liver abscess - Types, Causes, Symptoms, Risk factors and Prevention

Liver abscess definition

Liver abscess, also called hepatic abscess, is a severe medical condition of the liver. It is the collection of pus in the liver that can result from liver injury or the leakage of intestinal contents from the abdomen to the liver through the portal vein (the vein that carries nutrients from the digestive organ to the liver). Liver abscess typically occurs due to infection by micro-organisms and by trauma.

Pus is a fluid formed when the body fights off an illness. It is made up of dead cells and white blood cells. Sometimes, pus gathers in a pocket inside the liver rather than emptying from the infection site. Stomach pain and swelling may result from it. Usually, there is swelling and inflammation around an abscess.

The most common symptoms of the liver abscess include fever (continuous or intermittent), chills, pain in the right upper side of the stomach, loss of appetite, and malaise (general feeling of discomfort or illness). The most common signs include right shoulder pain, jaundice, hepatomegaly (enlargement of the liver), and pleural effusion (abnormal fluid buildup around the lungs). Complications include retroperitoneal extension (spread into the abdominal cavity), pulmonary emphysema (enlarged lung air sacs) and sepsis (a systemic infection causing organ dysfunction) are almost always incurable.  Liver abscess is treated by a hepatologist (liver specialist) and gastroenterologist.

Liver abscess meaning

Liver abscess is the combination of two words.

• The word “Liver” is derived from the old German word ‘librn’, which means the secreting organ of the body.
• "Abscess" is derived from the Latin word ‘abscesus’ in 1960s, which means the collection of pus in a few parts of the body.
  

Prevalence of liver abscess worldwide

Globally, an estimated 4–5 crore people become infected with liver abscess disease each year; most cases arise in developing countries, where the incidence of infection exceeds 5–10% and can occasionally reach 55%. Tropical developing nations, including those in Mexico, India, and tropical regions of Asia and Africa, have the highest prevalence.

Prevalence in India

Based on research fever and stomachache were the most frequently occuring symptoms among the Indian individuals assessed, and the etiology was higher in pyogenic compared to amoebic, other than idiopathic factors.

When the gender of the patient was considered, the prevalence of amoebic liver abscess was found to be 6.9% in females and 93% in males. When socioeconomic conditions were considered, the individuals with amoebic liver abscesses were found to be 62.3% from low socioeconomic conditions and 37.6% from high socioeconomic conditions.

Types of liver abscess

Based on the causative organism of liver abscess, it is categorized into two types.

• Pyogenic liver abscess 
• Bacterial abscess
• Fungal abscess
• Parasitic liver abscess

Pyogenic liver abscess

• Bacterial abscess: A common infectious condition called bacterial liver abscess is brought on by a variety of pathogens, including fungi, bacteria, and parasites. It is also called a pyogenic liver abscess (PLA). It can happen in several conditions, including trauma, colitis, pancreatitis, biliary tract disorders, and intravenous drug usage. Patients with weakened immune systems are frequently affected by a relatively new cause, Klebsiella pneumoniae. Symptoms related to endogenous endophthalmitis (EE), an uncommon and dangerous complications, may manifest before pyogenic liver abscess (PLA). 
• Fungal abscess: The most common cause of fungal abscesses is Candida albicans, which frequently affects immunocompromised people. They are an indication of a widespread fungal infection. There have also been reports of aspergillus species and cryptococcus infections causing hepatic abscesses. In people with weakened immune systems, fungal micro abscesses are scattered throughout the liver, showing up as many small lesions, often less than a centimeter in size. 

Parasitic abscess (Amoebic liver abscess) 

An accumulation of pus in the liver caused by the intestinal parasite Entamoeba histolytica is an amoebic liver abscess. Other names for the amoebic liver abscess are amebiasis and amoebic dysentery. Following an extraintestinal infection, the parasite may travel through circulation from the intestines to the liver. Food and water contaminated with faeces spread amebiasis. The use of human waste as fertilizer will occasionally cause liver abscesses. Additionally, amebiasis is transmitted by person-to-person interaction. Globally, infection is present. It is more prevalent in tropical regions with crowded housing and inadequate sanitation. India, Southeast Asia, Latin America, and Africa have extensive health problems with this. 

Humans can get hydatid disease, a parasitic infection, of which Echinococcus granulosus is the most common species. Dogs are the ultimate hosts of adult parasites, living in their stomachs. Cattle, horses, and sheep are intermediate hosts Humans are unusual hosts, as it is not common for them to become infected by consuming food and water contaminated with the stool of infected dogs. After being consumed, larvae of these eggs access the liver through the portal vein and are dispersed to various organs through the bloodstream. 

Liver abscess causes

A liver abscess is a collection of pus(fluid) due to the infection caused by various micro-organisms, leading to inflammation. Based on the type of causative organism, they are divided into different types as mentioned below: 

Pyogenic liver abscess causes

Different organisms causing pyogenic liver abscesses include Escherichia coli, staphylococcus aureus, streptococcus anginosus group, clostridium species, Bacteroides species, and klebsiella pneumoniae. There are various causes of pyogenic liver abscesses, they are:

• Bile duct problems: The function of the bile duct is to collect bile from the liver and transport it to the small intestine. It acts as a bridge between the liver and the duodenum of the small intestine.  Pyogenic liver abscess is an accumulation of pus in the liver because of bacterial infection, which destroys the liver parenchyma. This kind of infection is most frequently caused by biliary tract infection. 
• Through portal vein: Pyogenic liver abscesses commonly originate from abdominal infection and bowel content leakage. The portal vein (the vein that carries nutrients from the digestive organ to the liver) carries bacteria to the liver, where they settle down causing infection. The biliary system may potentially be the source of an infection.
• Through hepatic artery: When bacterial endocarditis (heart infection) or systemic bacteremia (blood infection) occurs, the hepatic artery might become contaminated. Stones, strictures (narrowing of the tube), or tumors that break the bile flow cause contamination of the bile, which then causes cholangitis, which causes liver abscesses. 
• From other parts of the abdomen: Pyogenic liver abscesses are frequently caused by the leakage of intraabdominal bowel contents, which travel to the liver through the portal circulation or directly spread when there is a biliary infection. Rarely a hepatic abscess caused by a foreign body that entered the digestive system is discovered. 80-90% of swallowed foreign bodies pass through the gut in less than a week without the patient realizing it and without any problems. 
• Injury: Blunt or penetrating trauma can result in intestinal puncture, a fistula (abnormal internal connection) to the liver, and the subsequent formation of an abscess can also induce pyrogenic liver abscess. Hepatic artery thrombosis (clot) and narrowing of the bile duct can lead to vascular compromise, which can result in liver abscesses in a transplanted graft. 

Amoebic liver abscess causes (Parasitic)

Parasites causing liver abscesses include Entamoeba histolytica, Echinococcus granulosus, protozoa, and helminths. The most common parasitic liver abscess is an amoebic liver abscess. Entamoeba histolytica is the protozoan that causes amebiasis, a parasitic infection spread through the fecal-oral pathway. The infection may show up as one or more liver abscess-related consequences, or it may be asymptomatic. The most typical extraintestinal sign of amebiasis is an amoebic liver abscess. It is the most prevalent organism. When it enters the portal system and migrates to the liver, it first causes amoebic colitis, followed by an amoebic liver abscess.

Echinococcus granulosus, another uncommon but important parasitic pathogen, creates a hepatic hydatid cyst leading to liver abscess. 

Liver abscess symptoms

The patient's experiences act as the signs and symptoms of the illness. While symptoms are understandable to the patient, signs are the signals observed by the doctor. The below list includes signs and symptoms of liver abscess:

• Fever and shivering 
• Vomiting 
• Severe weight loss
• Right upper stomach pain
• Dark urine and faeces 
• Nocturnal hyperhidrosis - sweating at nights 
• Jaundice – yellowish discoloration of eyes and skin
• Hepatomegaly- Enlarged liver
• Loose stools
  

Frequently Asked Questions (FAQs) on Liver abscess

What is a liver abscess?

A liver abscess is a pocket within the liver filled with infection or pus that disrupts the liver function and causes pain and discomfort. When the liver abscess bursts, it spreads infection wherever it goes.

What not to eat in a liver abscess?

Normally, proteins help in tissue repair in the body. They also protect the liver cells from harm and lipid accumulation. Proteins are not effectively digested in those whose livers are severely damaged. The brain may be affected by waste materials that accumulate. So, a high intake of protein needs to be avoided. Instead, carbohydrates and fats can be taken.

How to avoid liver abscesses?

Treating stomach infections as soon as possible is the best defense against liver abscesses. Most issues can be avoided with careful follow-up with the doctor and adherence to the recommended antibiotic prescription.

Is fasting good for liver repair?

Yes, according to several studies, fasting may enhance liver function and indicate a decrease in inflammation or fat deposition in the liver. Furthermore, during this fasting period, total cholesterol levels may also improve.

How big can a liver abscess be?

A large maximal diameter of the liver abscess upon admission indicated a severe condition, which ultimately prolonged hospitalization and complicated recovery. The average maximal diameter of the liver abscess was 5.4 ± 2.6 cm. For individuals with large liver abscesses, more intensive treatment approaches along with close monitoring are necessary. 

Can a liver abscess reoccur?

Yes, but it doesn't happen often. Additionally, it depends on the organism causing infection. Failure to adhere to antibiotic medication and to drain when necessary are risk factors for recurrence. Liver abscesses can manifest as sepsis or as an asymptomatic illness.

What is the incubation period of a liver abscess?

The incubation period depends on the type of organism. For Entamoeba histolytic, within 2 to 4 weeks of exposure, 80% of individuals will experience symptoms, which include fever, coughing, and dull, painful right upper quadrant or epigastric stomach pain.

How long after liver abscess can I consume alcohol?

Healthcare professionals’ advise liver abscess patients to not consume alcohol. Based on a study, alcohol consumption significantly increases the risk of developing both amoebic liver abscess and pyogenic liver abscess, mainly due to the toxic effects of alcohol on the liver.

Department of Hepatology