HBP - Liver - infections

Question 1

What is the incidence of liver abcess?

Answer 1

16/100000

Question 2

What are the three infective causes of liver abscess, in order of frequency?

Answer 2

Bacterial>amoebic>fungal

Question 3

List five of the most common bacterial infective agents in liver abscess

Answer 3

E. coli
Klebsiella pneumoniae
Bacteroides
Strep Faecalis

Question 4

What subgroups of streptococci can also cause liver abscess? Give examples.

Answer 4

Micro-aerophilic streptococci (e.g. strep milleri, dental and SBE)
Anaerobic streptococci (e.g. Peptostreptococcus)

Question 5

What type of parasite can cause liver abscess?

Answer 5

Amoeba

Question 6

What percentage of liver abscesses arise from a suppurative process elsewhere? From whence do the others arise?

Answer 6

75%
25% are cryptogenic

Question 7

Via what three mechanical routes do liver abscesses arise? Give examples

Answer 7

Biliary/GB
Abdominal sources (-> portal pyelophlebitis, e.g. appendicitis, diverticulitis)
Haematogenous (IV drug use, endocarditis, pneumonia

Question 8

List four underlying structural changes that may be associated with the aetiology of liver abscesses

Answer 8

• Post traumatic/infected haematoma
• Miscellaneous: e.g. infected cyst, complication post-embolisation
• Biliary obstruction (~25%)
• Underlying malignancy

Question 9

What a re the clinical features of liver abscess?

Answer 9

• Sepsis (fever, chills, malaise, fatigue
• 50% have pain, usually RUQ
• +/- tender hepatomegaly
• +/- jaundice

Question 10

What percentage of patients with liver abscess have multiple abscesses?

Answer 10

50%

Question 11

What percentage of left lobe and right lobe abscesses are multiple?

Answer 11

90 % of left lobe abscesses are multiple
10% of right lobe abscesses are multiple

Question 12

What are the most common blood test findings associated with liver abscesses?

Answer 12

Elevated WCC
Bilirubin is usually normal
ALP is elevated in 80%
Transaminases are elevated in 60%

Question 13

What are the CXR findings with liver abscess?

Answer 13

One third have changes in the right lung bases e.g. atelectasis or effusion

Question 14

What are the AXR findings in liver abscess?

Answer 14

May show hepatomegaly
+/- air/fluid level
sometimes portal venous gas

Question 15

What are the findings on CT and ultrasound that are suggestive a lesion is a pyogenic abscess?

Answer 15

Rim enhancement

Question 16

In an immunocompromised patient, what should you request on the culture of aspirate?

Answer 16

Mycobacterium and fungal cuture

Question 17

What are the radiologic features of pyogenic liver abscess on MRI?

Answer 17

High signal on T2

Question 18

What antibiotic regimen is recommended for liver abscess, and for how long?

Answer 18

Triple antibiotics for 4-6 weeks

Question 19

What antibiotic is recommended for entamoeba?

Answer 19

Metronidazole