Liver abscesses

Question 1

What is a liver abscess?

Answer 1

Liver abscess = purulent collection of pus within the liver parenchyma that result from bacterial, fungal or parasitic infection

Question 2

What is the aetiology of liver abscess?

Answer 2

Before antibiotics, most liver abscesses occurred following appendicitis

Abscesses can form in pre-existing lesions (including HCC) or in significant tumour necrosis

Most common source is from biliary tract abnormalities

Pyogenic liver abscess is often a polymicrobial infection

Commonly isolated organisms

• Gram -ve: Escherichia coli, Klebsiella
• Gram +ve: Streptococcal species, enterococci

Question 3

What are the risk factors for liver abscess?

Answer 3

• Biliary tract disease
• Age >50
• Malignancy (10-20%)
• DM
• Biliary/hepatic procedures
• Living in an amoebiasis endemic area

Question 4

What is the epidemiology of liver abscess?

Answer 4

Uncommon

Incidence increases with age

Occurring slightly more often in men

Most cases of amoebic infections occur in Central and South America, Africa and Asia

Question 5

What are the symptoms of liver abscess?

Answer 5

Acute
o RHS UQ pain
o High fever
o Nausea and vomiting

Longer duration (>1 month)
o	Pyrexia of unknown origin
o	Malaise
o	Anorexia and weight loss
o	Dull abdominal discomfort

Chest symptoms (33%)
o	Cough, SOB, chest pain

Symptoms of cause
o Amoebiasis - Diarrhoea, Weight loss
o Pyogenic - Cholangitis, Abdo infections, Sepsis

Question 6

What are the signs of liver abscess?

Answer 6

Tender hepatomegaly

Jaundice

Pyrexia

Signs of reactive RHS pleural effusion
o Dullness to percussion
o Decreased breath sounds

Question 7

What are the appropriate investigations for liver abscess?

Answer 7

Bloods
o FBC: Leukocytosis, neutrophilia, anaemia
o LFTs - ALP: Elevated, AST/ALT: Mildly elevated Bilirubin: Mildly elevated, Albumin: Low
o ESR/CRP: Raised
o Serology - Abs for Entamoeba histolytic: Positive in amoebiasis (Done in patients who live/have travelled to endemic areas)

Blood culture
o Positive for causative organism (50%)

Stool culture
o Positive for E. histolytica

Imaging
o Liver US - Variably echoic lesion
o Contrast abdo CT - Hypodense liver lesion
o CXR - RHS pleural effusion, Raised RHS hemidiaphragm

Abscess aspirate
o	MC+S
Pyogenic: Positive for bacterial organism
Fungal: Positive for candida
Amoebic: Anchovy sauce fluid