Liver abscess

Question 1

What are the pathogens that can cause liver abscess?

Answer 1

• Enterobacteriaceae family, e.g. Klebsiella pneumoniae, E coli
• Streptococcus
• Staphylococcus aureus
• Burkholderia pseudomallei
• Entamoeba histolytica: Single liver abscess, or culture-negative liver abscess

Question 2

What is the clinical definition of invasive liver abscess syndrome?

Answer 2

• Definite invasive syndrome: Klebsiella pneumoniae liver abscess + extrahepatic complications (especially CNS involvement, necrotising fasciitis, or endophthalmitis)
• Probable invasive syndrome: K pneumoniae liver abscess as sole manifestation

Question 3

What is the microbiological definition of klebsiella pneumoniae invasive liver abscess syndrome?

Answer 3

• Definite invasive syndrome: K pneumoniae liver abscess caused by K1 or K2 serotype
• Probable invasive syndrome: hypermucoviscous phenotype, defined by the string test, which monitors the formation of a viscous string of > 0.5 cm in length stretched by the inoculation loop

Question 4

What are the risk factors for klebsiella pneumoniae liver abscess?

Answer 4

• Diabetes (DM) is a major risk factor for the invasive syndrome
• Other risk factors: glucocorticoid therapy, alcoholism, malignancy, COPD
• Associated conditions: colorectal cancer (CRC), fatty liver
• K1 serotype is more prevalent in SG context

Question 5

What are the clinical manifestations of k pneumoniae liver abscess?

Answer 5

Fever, chills, abdominal pain/RUQ tenderness (most common); N&V in 25%

Question 6

what are the clinical manifestations of k pneumoniae invasive syndrome

Answer 6

Bacteraemia, endophthalmitis (eye), meningitis (CNS), necrotising fasciitis (MSK), or other extrahepatic infections that grow K pneumoniae

Lung: septic pulmonary emboli, empyema

MSK: osteomyelitis or subcutaneous/muscular abscesses are more common than necrotising fasciitis

Question 7

what are the investigations for k pneumoniae abscess?

Answer 7

Biochemical

• FBC: raised TW, low PLT
• Raised CRP
• Deranged LFT (AST, ALT, ALP, bilirubin)

Imaging: CT AP (more sensitive) or U/S abdomen –> identify liver abscess

Microbiological

• Culture (from blood or liver abscess aspirate) –> isolation of K pneumoniae with hypermucoviscous phenotype (highly suggestive of invasive strain)
• Multiplex PCR allows rapid detection of K1 and K2 serotypes

Question 8

what is the management for k pneumoniae abscess

Answer 8

• Strict glycaemic control

Treating liver abscess

• Third-gen cephalosporins (e.g. ceftriaxone) are mainstay in Asia
• If K pneumoniae is ESBL producing (rare) –> carbapenems are drug of choice

Treating metastatic infection
- Klebsiella meningitis –> third-gen cephalosporins
- Klebsiella endophthalmitis: IV and intravitreal abx required
o IV ceftazidime + amikacin
o Intravitreal cephalosporins + aminoglycosides