Liver Abscess

Pus-filled mass in the liver

Aetiology

Classification

Type
Causative Agent
Pyogenic liver abscess (PLA)
Bacteria (most common)
Amoebic liver abscess (ALA)
Entamoeba histolytica
Fungal liver abscess
Candida spp. (immunocompromised)

Pyogenic Liver Abscess

Common Sources
  • Biliary tract infection (most common)
  • Portal vein spread (appendicitis, diverticulitis)
  • Hematogenous spread (sepsis)
  • Direct extension or trauma
  • Cryptogenic (no identifiable source)
Common Organisms
  • Escherichia coli
  • Klebsiella pneumoniae
  • Streptococcus spp.
  • Anaerobes (Bacteroides)

Amoebic Liver Abscess

  • Extraintestinal manifestation of amoebiasis
  • Usually follows intestinal infection
  • Right lobe predominance

Clinical presentation

Symptoms

  • High fever, sweats
  • Leukocytosis
  • Upper abdominal pain
  • Pain can radiate to shoulder as enlarged liver irritates the diaphragm

Signs

  • Hepatomegaly
  • Ludwig Sign → Point tenderness over ICS VI along anterior midaxillary line

Investigations

Laboratory Tests

  • CBC: leukocytosis
  • LFTs: ↑ ALP, mild ↑ AST/ALT
  • CRP / ESR: elevated
  • Blood cultures (PLA)

Imaging (Key Diagnostic Tool)

Ultrasound Abdomen
  • First-line
  • Hypoechoic or complex lesion
CT Scan Abdomen (Gold Standard)
  • Defines size, number, location
  • Guides drainage
  • Detects complications

Microbiological Tests

  • Aspirate culture (PLA)
  • Amoebic serology (ALA)
  • Stool examination (may be negative)

Management

Pyogenic

Principles
  • Start empirical broad-spectrum IV antibiotics
  • Cover Gram-negative bacilli, Gram-positive cocci, and anaerobes
  • Duration: 4–6 weeks (IV → oral)
Regimen
Dose
Route
Duration
Notes
Ceftriaxone + Metronidazole
Ceftriaxone 2 g 2x1 + Metronidazole 500 mg 3x1
IV
2–3 w IV → oral
Common first-line
Piperacillin–Tazobactam
4.5 g 3-4x daily
IV
2–3 w IV → oral
Severe sepsis
Cefepime + Metronidazole
Cefepime 2 g 2-3x/day + Metronidazole 500 mg 3x1
IV
As above
Resistant Gram-negatives
Meropenem
1 g 3x1
IV
As above
ESBL / severe infection
Step-down (oral)
Amoxicillin–clavulanate 625–875 mg 2-3x/day
PO
Complete 4–6 w
After clinical improvement

Amoebic

Principles
  • Treat tissue invasion first, then eradicate luminal cysts
  • Drainage usually not required
      • 🚫 Metronidazole alone is insufficient → always add a luminal agent.
Drug
Dose
Route
Duration
Purpose
Metronidazole
750 mg 3x1
PO/IV
7–10 days
Tissue amoebicide (first-line)
Tinidazole (alternative)
2 g 1x1
PO
5 days
Better tolerance
Diloxanide furoate
500 mg 3x1
PO
10 days
Luminal eradication
Paromomycin (alternative)
25–30 mg/kg/day in 3 doses
PO
7 days
Luminal agent
Iodoquinol (alternative)
650 mg 3x1
PO
20 days
Luminal agent

Drainage Indications

  • Abscess >5 cm
  • Left lobe abscess
  • Poor response to antibiotics
  • Impending rupture
Methods:
  • Percutaneous needle aspiration
  • Percutaneous catheter drainage
  • Surgical drainage (rare)