Hepatic Abscess, Pyogenic

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 or gastrointestinal tract (eg, a fish or chicken bone)

• 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

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

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

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 radiographs 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

  • Usually seen in the setting of systemic candidiasis

  • Characteristic appearance on CT scan is that of multiple "bulls-eyes"

  • However, imaging studies may be negative in neutropenic patients

Medications

• Use antimicrobial agents (a third-generation cephalosporin [eg, ceftriaxone 2 g intravenously every 24 hours] and metronidazole [500 mg every 6 hours intravenously]) that are effective against coliform organisms and anaerobes

• Hepatic candidiasis often responds to intravenous amphotericin B (total dose of 2–9 g)

Surgery

• If the abscess is at least 5 cm in diameter or the response to antibiotic therapy is not rapid, intermittent needle aspiration, percutaneous or endoscopic ultrasound-guided catheter drainage or stent placement, or if necessary, surgical (eg, laparoscopic) drainage should be done

• Fungal abscesses require drainage

Prognosis

• The mortality rate is still substantial (≥ 5%) and is highest in underlying biliary malignancy or severe multiorgan dysfunction

• Other risk factors for mortality include

  • Older age

  • Cirrhosis

  • Chronic kidney disease

  • Cancer

• Fungal abscesses are associated with mortality rates of up to 50%

When to Admit

• All patients