Liver Abscess

Alternative names: Hepatic abscess, Hepatic amebiasis, Extraintestinal amebiasis, Amebic liver

A liver abscess is a pus-filled cyst inside the liver.  It is relatively rare, affects mainly the elderly, and is often caused by bacteria spreading through the blood from nearby abdominal structures such as the appendicitis, intestines (diverticulitis), or bile ducts.

Incidence; Causes and Development; Contributing Risk Factors

Because of the liver's excellent ability to remove bacteria, infection is relatively rare.  However, liver abscess is detected in approximately 1-in-200 autopsies.  It is most common in those over the age of 60.  Men and women are equally affected.

There are three types of liver abscess:

• Pyogenic liver abscess (PLA), accounting for some 80% of cases, can be caused by a variety of bacteria.  Escherichia coli and Klebsiella pneumoniae are the two most commonly detected.
• Amebic abscess, accounting for some 10% of cases, is caused by Entamoeba histolytica
• Fungal abscess, accounting for under 10% of cases, is usually caused by Candida

Appendicitis was previously the main cause of liver abscess, but due to improved diagnostic and treatment techniques, it now causes only around 10% of cases.

Biliary tract disease is now the most common cause of PLA, and usually leads to multiple abscesses.  Anything that constricts the bile duct can cause problems, for example bile stones, bile duct cancer, biliary stricture, or congenital disease: once bile flow is obstructed, bacteria can multiply.

Bacteria from bloodstream infections or other infections within the abdomen can also spread to the liver and cause liver abscess, for example diverticulitis or perforated bowel.

In many cases, the cause remains unknown.

Risk factors for liver abscess include high alcohol intake, cancer, cancer treatments, corticosteroids, organ transplant, weakened immune system, malnutrition, trauma to the liver, Diabetes, old age, pregnancy, recent abdominal surgery, recent endoscopy of the bile ducts, tropical travel, Crohn's disease, abdominal or gastrointestinal infection, and steroid use.

Signs and Symptoms

Symptoms of liver abscess include:

• Intense continuous or stabbing upper-right abdominal pain
• Fever
• Nausea
• Chills
• Sweating
• Diarrhea (affects 1-in-3 patients)
• Clay-colored stools
• Dark urine
• General malaise
• Lethargy
• Painful breathing (Pleurisy)
• Joint pain
• Coughing
• Non-stop hiccups (a rare finding)
• Jaundice (yellowing of the skin and eyes)
• Loss of appetite
• Unexplained weight loss

More serious symptoms, which may indicate a life-threatening condition, include:

• Mental changes such as confusion, delirium, hallucinations, delusions
• High fever (over 101°F)
• Jerky movements
• Rapid heart rate
• Breathing problems (shortness of breath, difficulty breathing, wheezing, or choking)
• Severe abdominal pain
• Vomiting

Diagnosis and Tests

A diagnostic workup generally includes several of the following:

• Abdominal ultrasound
• Abdominal CT scan or MRI
• Complete blood count
• Liver abscess aspiration (verifies bacterial infection)
• Liver scan
• Liver function tests
• Blood test
• Stool test

Treatment and Prevention

When detected in time, a liver abscess is usually treatable.  Many different antibiotics may be used to treat liver abscess, the choice being determined by the nature of the infecting organism and the severity of the infection.  Metronidazole (Flagyl), Aminoglycosides, Clindamycin or tinidazole (Tindamax) are commonly used.

The drugs paromomycin and diloxanide are also administered, usually after successful treatment of the liver abscess, to clear the intestine of infection and prevent recurrence.

In severe cases, the abscess may be drained using laparoscopic surgery or percutaneous drainage and aspiration via needle or catheter to relieve the pain.

Prognosis; Complications

Despite improvements in modern medicine, the mortality rate for liver abscess remains at 5-30%.  Prognosis is worse for men than for women.  Untreated, it is always fatal.

Complications are severe and often fatal.  The abscess may rupture and spread into the abdominal cavity, the lungs, the lining of the lungs or heart, or to the brain.  This can lead to empyema, endocarditis, liver failure, pleural effusion, or sepsis.