What is the recommended treatment for amoebiasis of the liver?

Treatment of Amoebiasis of the Liver

Metronidazole 500 mg three times daily orally for 7-10 days is the recommended first-line treatment for amoebiasis of the liver, with tinidazole 2 g daily for 3 days as an effective alternative that may cause fewer side effects. 1

Diagnosis and Clinical Presentation

Amoebiasis of the liver (amoebic liver abscess) should be suspected in patients with:

• Fever (present in 67-98% of cases)
• Localized abdominal pain (80-95% of cases)
• Hepatomegaly (43-93% of cases)
• Raised right hemi-diaphragm on chest X-ray
• History of travel to or residence in endemic areas

Only 20% of patients will have a history of dysentery, and only 10% will have concurrent diarrhea at presentation. 1

Diagnostic Workup

1. Laboratory tests:

   • Neutrophil leukocytosis >10×10⁹/L
   • Elevated inflammatory markers
   • Deranged liver function tests (particularly elevated alkaline phosphatase)
   • Amoebic serology (indirect hemagglutination has >90% sensitivity)

2. Imaging:

   • Ultrasound should be performed in all patients
   • Consider CT scan if ultrasound is negative but clinical suspicion remains high
   • Main differential diagnosis is pyogenic abscess (more likely to be multiple in older patients)

3. Aspiration:

   • Only indicated for diagnostic uncertainty
   • Should be performed after checking hydatid serology in patients from endemic regions 1

Treatment Algorithm

First-Line Treatment

• Metronidazole: 500 mg three times daily orally for 7-10 days (>90% cure rate) 1, 2

Alternative Treatment

• Tinidazole: 2 g once daily for 3 days (may cause less nausea than metronidazole) 1, 3

Response to Treatment

• Most patients will respond within 72-96 hours 1
• Clinical improvement should be evident by reduction in fever, pain, and hepatomegaly

Follow-Up Treatment

• After completion of metronidazole or tinidazole, all patients should receive a luminal amoebicide to prevent relapse, regardless of stool microscopy results:
  • Diloxanide furoate: 500 mg orally three times daily for 10 days, OR
  • Paromomycin: 30 mg/kg/day orally in 3 divided doses for 10 days 1

Special Considerations

Invasive Procedures

• Surgical or percutaneous drainage is rarely required and should only be considered if:
  • Diagnostic uncertainty persists
  • Symptoms persist after 4 days of appropriate treatment
  • Risk of imminent rupture exists (particularly for left-lobe abscesses that might rupture into critical sites like the pericardium) 1, 2

Empiric Treatment

• In patients with systemic inflammatory response syndrome, consider adding broad-spectrum antibiotics (e.g., ceftriaxone) until the diagnosis is confirmed, as pyogenic abscess remains in the differential 1

Treatment Efficacy

• Research shows that metronidazole alone successfully treats over 90% of amoebic liver abscesses without need for invasive procedures 2
• Some studies suggest tinidazole may have a more rapid therapeutic effect and better tolerability than metronidazole 3

Pitfalls and Caveats

1. Do not rely on stool microscopy alone for diagnosis, as it is often negative in patients with amoebic liver abscess 1

2. Do not delay treatment while awaiting confirmatory tests if clinical suspicion is high; empiric therapy should be started promptly in patients with suggestive history, epidemiology, and imaging 1

3. Do not forget the luminal amoebicide after treatment with metronidazole/tinidazole to prevent relapse 1

4. Do not routinely perform aspiration unless there is diagnostic uncertainty, persistent symptoms despite adequate therapy, or risk of rupture 1, 2

5. Do not miss hydatid disease as a differential diagnosis in patients from the Middle East, Central Asia, and Horn of Africa; hydatid serology should be checked before aspiration in these patients 1