Hepatic Abscess, Pyogenic

Key Features

Essentials of Diagnosis

• Fever, right upper quadrant pain, jaundice

• Often in setting of biliary disease but up to 40% are cryptogenic in origin

• Detected by imaging studies

General Considerations

• The liver can be invaded by bacteria via

  • The portal vein (pylephlebitis)

  • The bile duct (acute "suppurative" [formerly ascending] cholangitis)

  • The hepatic artery, secondary to bacteremia

  • Direct extension from an infectious process

  • Traumatic implantation of bacteria through the abdominal wall

• Acute cholangitis resulting from biliary obstruction due to a stone, stricture, or neoplasm is the most common identifiable cause of hepatic abscess in the United States

• Statin use may reduce the risk of pyogenic liver abscess

• In 10% of cases, liver abscess is secondary to appendicitis or diverticulitis

• Up to 40% of abscesses have no demonstrable cause and are classified as cryptogenic; a dental source is identified in some such cases

• The most frequently encountered organisms

  • Escherichia coli

  • Klebsiella pneumoniae

  • Proteus vulgaris

  • Enterobacter aerogenes

  • Multiple anaerobic species

• Liver abscess caused by virulent strains of K pneumoniae

  • May be associated with thrombophlebitis of the portal or hepatic veins and hematogenously spread septic ocular or CNS complications

  • May be gas-forming, associated with diabetes mellitus, and result in a high mortality rate

• Staphylococcus aureus is usually the causative organism in chronic granulomatous disease

• Hepatic candidiasis, tuberculosis, and actinomycosis are seen in immunocompromised patients and those with hematologic malignancies

• Rarely, hepatocellular carcinoma can present as a pyogenic abscess because of tumor necrosis, biliary obstruction, and superimposed bacterial infection

• Even more rarely, liver abscess may be the result of a necrotic liver metastasis

• The possibility of an amebic liver abscess must always be considered

Clinical Findings

Symptoms and Signs

• The presentation is often insidious

• Fever is almost always present and may antedate other symptoms or signs

• Pain, localized to the right upper quadrant or epigastric area, may be a prominent complaint

• Jaundice, tenderness in the right upper abdomen, and either steady or spiking fever are the primary physical findings

• Risk of acute kidney injury is increased

Differential Diagnosis

• Cholecystitis

• Cholangitis

• Acute hepatitis

• Amoebic liver abscess

• Appendicitis

• Right lower lobe pneumonia

• Pancreatitis

• Echinococcosis (hydatid disease)

• Liver mass, eg, hepatocellular carcinoma

Diagnosis

Laboratory Tests

• Leukocytosis with a shift to the left

• Liver biochemical tests are nonspecifically abnormal

• Blood cultures are positive in 50–100% of cases

Imaging Studies

• Chest films usually reveal elevation of the diaphragm if the abscess is on the right side

• Ultrasonography, CT, or MRI may reveal the presence of intrahepatic lesions

• On MRI, characteristic findings include high signal intensity on T2-weighted images and rim enhancement

• Hepatic candidiasis

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