Amoebic Liver Abscess
A liver infection caused by an amoeba parasite, leading to a pus-filled cavity, high fever, and right upper belly pain.
Emergency Management: Rupture into adjacent cavities requiring emergent drainage and intensive care.
A collection of pus in the liver caused by the protozoan parasite Entamoeba histolytica, representing the most common extraintestinal manifestation of amebiasis.
Detailed Overview
Following intestinal infection, trophozoites invade the colonic mucosa, enter the portal circulation, and travel to the liver. There, they cause tissue necrosis and abscess formation. It is most common in tropical regions with poor sanitation.
Epidemiology & Demographics
Most common in tropical/subtropical regions (India, Africa, Mexico). Predominantly affects young to middle-aged males (male-to-female ratio up to 10:1).
Etiological Mechanism
Infection by Entamoeba histolytica.
Primary Causes
Ingestion of food or water contaminated with E. histolytica cysts.
Ingested cysts excyst in the terminal ileum. Trophozoites colonize the large intestine, induce apoptosis of colonic epithelial cells, and invade the portal venous system. In the liver, they cause microthrombosis and infarction, leading to a focal area of necrosis. The abscess contains "anchovy paste" like fluid (necrotic tissue, blood) rather than true purulent pus.
Diagnostic Criteria & Guidelines
Imaging demonstrating a liver abscess combined with positive E. histolytica serology (IgG antibodies) or positive antigen/PCR testing.
Tissue amebicide: Metronidazole 750 mg orally TID for 7-10 days (or Tinidazole 2 g daily for 3-5 days). This must be followed by a luminal amebicide to eradicate intestinal carriage: Paromomycin 30 mg/kg/day orally in 3 divided doses for 7 days.
Second-Line & Adjunctive Therapy
If intolerant to metronidazole, long courses of broad-spectrum antibiotics or aspiration. Aspiration/drainage is generally reserved for large abscesses (>5-10 cm), high risk of rupture, left lobe abscesses (risk of pericardial rupture), or lack of response to metronidazole after 3-5 days.
Surgical & Procedural Management
Percutaneous needle aspiration or pigtail catheter drainage if indicated. Open surgical drainage is rarely needed unless rupture into the abdomen occurs.
Patient Counseling & Advice
Emphasize that two separate drugs are needed: one to kill the amoeba in the liver, and another to clear it from the gut to prevent recurrence.
Follow-Up & Monitoring Schedule
Clinical resolution is fast (fever abates in 3-4 days). Imaging resolution of the abscess cavity takes months and routine follow-up ultrasounds are not needed if asymptomatic.
Preventive Strategies
Boil drinking water or use appropriate microfiltration/iodine treatment in endemic regions. Proper hand hygiene.
Excellent with appropriate prompt antibiotic therapy; mortality is <1% in uncomplicated cases.